A part 1 abstract.cdr

National Conference on

Paleogene of the Indian Subcontinent ORGANIZING COMMITTEE Patron Harbans Singh Director General Geological Survey of India Presidents Sunil Bajpai Siddharth Swaroop Director Dy. Director General & HoD Birbal Sahni Institute of Paleobotany, Geological Survey of India, Lucknow Lucknow Conveners Satish C. Tripathi Amit Dharwadkar Organizing Secretaries Vandana Prasad S.R. Mishra Finance Secretary A.P. Rai National Advisory Committee A.K. Gupta, WIHG, Dehradun Ashok Sahni, Lucknow University B.P. Singh, BHU D.D. Bhattacharya, GSI, Lucknow D.D. Joshi, GSI, Lucknow G.C. Kandpal, GSI, Lucknow G.V.R. Prasad, Delhi University G.S. Jaggi, GSI, Delhi G.V. Vidyasagar, GSI, Lucknow K. Balasubramanian, GSI, Kolkata J.S. Ray, PRL, Ahmedabad Kanchan Pande, IIT, Bombay K.K. Agarwal, Lucknow University M. Raju, GSI, Kolkata Mallickarjun Joshi, BHU Mervin D'Souza, WOCS, Delhi O.N. Bhargava, Chandigarh P.S. Parihar, AMD, Hyderabad

R.P. Rai, GSI, Lucknow Rahul Garg, BSIP, Lucknow Rajesh Asthana, GSI, Kolkata Rajiv Nigam, NIO, Goa Rashmi Srivastava, BSIP, Lucknow S. Kannan, GSI, Kolkata S. Nateshan, GSI, Faridabad S.K. Tandon, IIT, Kanpur S.P. Nim, GSI, Jammu S.S. Nayak, GSI, Lucknow S.W.A. Naqvi, NIO, Goa Sabyasachi Shome, GSI, Kolkata Sandeep Singh, IIT, Roorkee Santosh Kumar, Kumaun University, Nainital T.S. Pangtey, GSI, Dehradun V. Ravikant, IIT, Kharagpur Vibhuti Rai, Lucknow University


Paleogene of the Indian Subcontinent PREFACE The movement of the Indian Plate across the equator during the Palaeogene Period caused significant palaeobiological and palaeogeographical changes over the Indian subcontinent, which was still in isolation. Therefore, the geological data set from Indian subcontinent provide unique information on global climatic changes and impact on life. The demise of dinosaurs at the Cretaceous/Paleogene boundary, the cessation of voluminous outpouring of Deccan basaltic magma and evolution of mammals of modern affinity are some of the important geological and biological events associated with the onset of Cenozoic Era about 65 million years ago. The final closure of Tethys sea resulted in significant changes in paleoocean circulation and an initiation of the Indian monsoon. The signatures of global warming and cooling events in the Indian Paleogene sedimentary sequence bear imprint of important paleoclimatic records. The coal and lignite deposits; and hydrocarbon resources of Paleogene Period are also crucial for our economic development. Extensive research on various aspects of Paleogene of India has been carried out by various research institutions and universities and it was the right time to organize a conference to bring out recent developments and to identify the gaps in information. In the present context, it is very important to have a multidisciplinary approach based on mutual collaboration. Such conferences are occasions to develop mutual ties for more effective research. The conference being organized jointly with the Birbal Sahni Institute of Paleobotany, Lucknow, is an initiative to enhance our scientific platform, strengthen mutual understanding and to provide focused direction for future research. This is the requirement of the time as we are looking towards the mega geoscientific event- 36th International Geological Congress, 2020, Delhi. The Paleogene Conference-2015 is marked as a run up event to the 36th IGC. I hope the scientific deliberations during the conference will highlight new researches and identify gaps for future course of research. I wish all the success for its organization.

Harbans Singh Director General Geological Survey of India


Paleogene of the Indian Subcontinent INTRODUCTION The Paleogene, comprising the early part of Cenozoic Era, was the most dynamic period in the Earth's history with profound changes in the biosphere and geosphere. The Period began with post-K/T mass extinction event at ~65.5 Ma and ended at ~23 Ma, when the first Antarctic ice sheet appeared in the southern hemisphere. The early Paleogene (Paleocene-Eocene) has been considered a globally warm period, superimposed on which were several transient hyperthermal events of extreme warmth. Amongst them, the Palaeocene Eocene Thermal Maxima (PETM) boundary interval is the most prominent extreme warming episode of 200Ka duration. PETM is characterized by 2-6‰ negative carbon isotope excursion in both terrestrial and marine sediment records, worldwide. The event coincides with the Benthic Extinction Event (BEE) in deep sea and Larger Foraminifera Turnover (LFT) in shallow seas. Rapid ~60-80 warming of high latitudinal regions led to major faunal and floral turnovers in continental, shallow-marine and deepmarine realms. Emergence, dispersal of mammals of modern aspect including Artiodactyls, Perissodactyls and Primates (APP); evolution and expansion of tropical vegetation are some of the significant features of the Paleogene warm world. In the Indian subcontinent, the beginning and end of the Paleogene is marked by varied events which resulted in shaping various physiographic features of the subcontinent. Indian subcontinent lay within the equatorial zone during the earliest part of Paleogene. Carbonaceous shale, coal and lignite deposits of Paleogene age (~55.5-52 Ma) of the western and north-eastern margins of the Indian subcontinent are rich in their fossil content and provide information on climate as well as evolution and paleobiogeography of tropical biota. Indian Paleogene deposits of trans-Himalayas also provide information pertaining to the timing of India-Asia collision. Precise age of the cessation of marine sedimentation in the Indus Suture Zone in trans-Himalayas and the initiation of continental molasse sedimentation is required for determination of the exact timing of India-Asia collision. Besides, development of facies models based on the sedimentological, biotic and geochemical signatures of Paleogene deposits from Himalayan foothills can also help in the understanding of early history of India-Asia collision. Indian Paleogene rocks are exposed in the Himalayan and Arakan mountains; Assam and the shelf basins of Kutch-Saurashtra, Western Rajasthan and Tiruchirapalli-Pondicherry. The stratigraphic correlation of various Paleogene sequences of the Indian subcontinent is required to reconstruct the Paleogene paleogeography and paleodepositional models for the various basins.


Paleogene of the Indian Subcontinent

The hydrocarbon resources of various Paleogene basins and sub-basins of Indian subcontinent are also important from the economic viewpoint. Multidisciplinary approach is required for understanding the geodynamic evolution and associated events during the Paleogene. Indian Paleogene history recorded the Earth's system processes operative during intervals of global warming and cooling due to major tectonic activities. In view of the above, the National Conference on Paleogene of the Indian Subcontinent is being organised by the Geological Survey of India and Birbal Sahni Institute of Palaeobotany, to bring recent researches to light and to identify future thrust areas of research and collaboration. Sunil Bajpai President, Paleogene Conference-2015 Director Birbal Sahni Institute of Paleobotany, Lucknow

Siddharth Swaroop President, Paleogene Conference-2015 Dy. Director General & HoD Geological Survey of India, Lucknow

CONTENTS 1.

K-T BUNDARY ASTEROIDAL IMPACT, CRUST-MANTLE STRUCTURE AND GEODYNAMICS OF THE WESTERN CONTINENTAL MARGIN OF INDIA: GEOPHYSICAL PERSPECTIVE O. P. Pandey

1

2.

GLOBAL PALEOGEOGRAPHY DURING K/T BOUNDARY AND PALEOGENE WITH SPECIAL REFERENCE TO THE INDIAN SUBCONTINENT Vinod C. Tewari

2

3.

ANALYSIS OF LONG WAVELENGTH GRAVITY DATA OVER K-T IMPACT STRUCTURE, OFFSHORE MUMBAI, INDIA Satyajit Dutta and NimishaVedanti

3

4.

ORGANIC MATTER FROM MARINE SEDIMENTS OF THE LATE CRETACEOUS-EARLY PALEOCENE UM-SOHRYNGKEW RIVER SUCCESSION, MEGHALAYA, INDIA: PALAEOENVIRONMENTAL INFERENCES AND K/PG TRANSITION Sucharita Pal, J. P. Shrivastava, Sanjay K. Mukhopadhyay and Sandeep Hamilton

4

5.

DISCOVERY OF CALCAREOUS NANNOFOSSILS FROM DECCAN INTERTRAPPEAN BEDS NEAR MANAWAR, CENTRAL INDIA Jyotsana Rai, Vivesh V Kapur, Abha Singh, Sunil Bajpai and Shailesh Agrawal

5

6.

ELASTIC PROPERTIES OF AMBENALI AND POLADPUR FORMATIONS OF DVP: NEW FINDINGS Nimisha Vedanti, Ajay Malkoti, Satyajit Dutta, O.P. Pandey

6

7.

PALEOGENE OF THE INDIAN PETROLIFEROUS BASINS: LARGER FORAMINIFERAL PROXIES AND ROLE IN HYDROCARBON EXPLORATION Sudhir Shukla

7

8.

PALEOGENE OF GUJARAT AND INDUSTRIAL GROWTH D. U. Vyas

9

vi

9.

THE TERTIARY PETROLEUM SYSTEM OF NORTHWEST HIMALAYA: CHALLENGES IN EXPLORATION Manoj Kumar Baruah

10

10. PALYNOFACIES ANALYSIS AND HYDROCARBON SOURCE ROCK POTENTIAL OF BARSINGSAR LIGNITES, BIKANER DISTRICT, WESTERN RAJASTHAN, INDIA Sikander, O.P. Thakur and N.N. Dogra

11

11. APPLICATION OF DEPOSITIONAL ENVIRONMENTAL MODELLING AS A TOOL TO LIGNITE EXPLORATION: A CASE STUDY FROM NORTH-WEST PALANA BASIN, JAISALMER AND BIKANER DISTRICTS, RAJASTHAN Rajuram Saraswat, Bijoy Ashish Sen, Mohammed Ahmed and Shivaji Gupta

12

12. ORGANIC PETROLOGY OF PALEOGENE COAL DEPOSITS OF GARO HILLS, MEGHALAYA, INDIA Alok K. Singh

13

13. FORCING FACTORS FOR THE LATE PALEOCENE (57.9-54.7 MA) TRANSGRESSION AND LATEST MIDDLE EOCENE (41. 3-38.0 MA) REGRESSION ON THE INDIAN SUBCONTINENT B. P. Singh, Y. Raghumani Singh,D. S. Andotra, A. Patra, V. K. Srivastava, Venus Guruaribam ,Umarani Sijagurumayum and G. P. Singh

14

14. PALEOGENE BASIN FORMING AND MODIFYING TECTONICS AS REVEALED IN SEISMIC SECTIONS OF ARABIAN SEA AND BAY OF BENGAL K.S. Misra

15

15. A COMPARATIVE STUDY OF THE DEFORMATION PATTERN AND SEDIMENTATION HISTORY OF THE SUB-HIMALAYAN LOWER CENOZOIC SUCCESSION OF JAMMU AND HIMACHAL PRADESH: THE TECTONIC IMPLICATIONS Prabir Dasgupta, Gautam Ghosh and Sumit Dey

16

16. PALAEOGENE–NEOGENE TECTONICS AND CONTINENTAL AGGRADATIONAL BASINS IN NORTH-WESTERN INDIA– IMPLICATIONS FOR GEOLOGICAL EVOLUTION OF THAR DESERT Sudesh Kumar Wadhawan

18

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17. PALEOGENE TECTONIC AND SEDIMENTATION RECORDS OF THE ANDAMAN-NICOBAR ACCRETIONARY RIDGE P. C. Bandopadhyay

20

18. ICHNOLOGY OF A PALEOGENE FLUVIAL MEANDERING CHANNEL-LEVEE COMPLEX: MOHAMAD KI DHANI SANDSTONE, JAISALMER BASIN, INDIA Bhawanisingh G. Desai

22

19. STUDY OF BIOEROSION AND ENCRUSTATION FROM THE MIDDLE EOCENE OF KUTCH, GUJARAT AND ITS BEARING ON BASIN EVOLUTION Sayoni Mitra Das and Kalyan Halder

23

20. PALEOGENE SEDIMENTATION IN PARTS OF KOHIMA SYNCLINORIUM, NAGALAND, INDIA: CHANGES TROUGH TIME S. K. Srivastava and A. Moalong Kichu

24

21. PALEOGENE OF THE LESSER HIMALAYA: A REVIEW OF CONTROVERSIES O. N. Bhargava

25

22. DISTRIBUTION OF TERTIARY SUCCESSION IN NEPAL LESSER HIMALAYA Megh Raj Dhital

26

23. SEDIMENTARY RESPONSES TO FORCED REGRESSION ACROSS SUBATHU - DAGSHAI BOUNDARY IN NW HIMALAYAN FORELAND Partha Pratim Chakraborty and Melinda K. Bera

29

24. PALAEODEPOSITIONAL AND MICROFACIES ANALYSIS OF PALAEOGENE SUBATHU FORMATION, LESSER HIMALAYA IN GARHWAL AND MUSSOORIE SYNCLINE, UTTRAKHAND S. R. Mishra, Rabishankar Karmakar, Rajuram Sarswat, Srirupa Gupta

30

25. FACIES ANALYSIS AND DEPOSITIONAL ENVIRONMENT OF THE LATE PALEOCENE-EARLY EOCENE NAREDA FORMATION, KUTCH, WESTERN INDIA V. K. Srivastava and B. P. Singh

32

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26. SEQUENCE STRATIGRAPHIC SIGNIFICANCE OF DISCONTINUITY SURFACES DURING PALAEOGENE: INSIGHTS FROM CORRELATION OF KACHCHH AND JAISALMER BASINS OF WESTERN INDIA Rajendra Dutt Saklani and Bhawanisingh G. Desai

33

27. PALEOGENE EVENTS OF THE MANIPUR REGION, INDIA Y. Raghumani Singh, Umarani Sijagurumayum and B.P. Singh

34

28. PALYNOFACIES STUDY OF LAKADONG LIMESTONE (LATE PALEOCENE) OF MAWSYNRAM AREA, SHILLONG PLATEAU, MEGHALAYA: IMPLICATIONS FOR SEQUENCE STRATIGRAPHIC SUBDIVISION Bikash Gogoi, Vandana Prasad and Rahul Garg

35

29. SOME FIELD OBSERVATIONS ON THE GEOLOGY OF THE PALEOGENE BELT OF THE SIMLA HILLS, HIMACHAL PRADESH, INDIA K. Milankumar Sharma, Ram Jivan Singh, Tomoghno Ghosh and Pankaj Kumar

36

30. GEOCHEMICAL PROVENANCE OF PALEOGENE SEDIMENTS IN ANDAMAN FOREARC: IMPLICATIONS FOR PALEOGENE DRAINAGE IN SOUTH ASIA Jyotiranjan S. Ray and Neeraj Awasthi

38

31. SIGNATURES OF PALEOCENE–EOCENE THERMAL MAXIMUM IN SUBATHU SUCCESSION, NW SUB-HIMALAYA, INDIA Smita Gupta and Kishor Kumar

39

32. QUANTIFICATION OF WARMING EVENTS DURING THE PALEOGENE IN INDIA: EVIDENCE FROM FOSSIL CLIMATES Gaurav Srivastava

40

33. EFFECT OF GLOBAL WARMING ON DIVERSITY PATTERN IN NYPA MANGROVES ACROSS PALEOCENE-EOCENE TRANSITION IN THE PALAEO-EQUATORIAL REGION OF THE INDIAN SUBCONTINENT Jyoti Srivastava and Vandana Prasad

41

34. HOW OLD IS THE INDIAN MONSOON SYSTEM? GEOCHEMICAL EVIDENCES FROM THE ANDAMAN FORE-ARC BASIN Neeraj Awasthi and Jyotiranjan S. Ray

42

ix

35. TAPHONOMY AND PALEOECOLOGY OF PALEOCENE-EOCENE CALCAREOUS ALGAE FROM MEGHALAYA, N-E INDIA Suman Sarkar

44

36. SEDIMENTOLOGICAL INVESTIGATION OF THE EARLY PALEOGENE SUCCESSION OF JAISALMER BASIN, RAJASTHAN WESTERN INDIA A.Patra and B. P. Singh

45

37. PALYNOLOGICAL STUDIES OF MATANOMADH FORMATION OF PALAEOCENE AGE FROM KACHCHH DISTRICT, GUJARAT Arvind Kumar Mathur

46

38. DRIFTING INDIA: A PALAEOGENE GARDEN OF EDEN? Ashok Sahni

47

39. DINOFLAGELLATE CYST BIOCHORONOLOGY OF THE LIGNITE ASSOCIATED SUCCESSION (KHARSALIA FORMATION), BHAVNAGAR, GUJARAT, INDIA Rahul Garg, Sunil Bajpai, Vivesh Vir Kapur and A. S. Maurya

48

40. PALYNOLOGICAL EVIDENCE FOR AGE AND PALAEOENVIRONMENT OF PANANDHRO LIGNITE MINE SUCCESSION, WESTERN KUTCH, INDIA Rahul Garg, M. R. Rao, Sunil Bajpai and Poonam Verma

49

41. EOCENE-OLIGOCENE PLANKTIC FORAMINIFERAL BIOSTRATIGRAPHY IN ARABIAN SEA AND WESTERN TROPICAL INDIAN OCEAN Prabha Kalia and L. R. Sahu

51

42. FOSSILS FROM KASAULI AND NYOMA: PALEOLATITUDINAL SIGNIFICANCE AND THEIR ROLE IN UNDERSTANDING THE TIMINGS OF INDO–CHINA COLLISION Ritesh Arya

53

43. NEW DATA ON BASAL EOCENE LAND MAMMAL FAUNA FROM WESTERN INDIA: FOCUS ON PERISSODACTYLS Vivesh V. Kapur and Sunil Bajpai

55

44. NANNOFOSSIL IMPRINTS OF PALEOGENE TRANSGRESSIVE EVENTS IN INDIA Jyotsana Rai

57

x

45. EOCENE FORAMINIFERA FROM THE NAGA-MANIPUR HILLS OF INDO-MYANMAR RANGE, NORTHEAST INDIA: FRESH INSIGHTS Kapesa Lokho

61

46. THE OLIGOCENE CORALS HAD CIRCUMTROPICAL DISTRIBUTION Patrali Sinha and Kalyan Halder

62

47. IMPLICATION OF THE OCCURRENCE OF MINUTE BIOTIC BODIES ON CONJOINED TESTS OF NUMMULITES AFF. NUMMULITESACUTUS (SOWERBY) IN THE SUBSURFACE EOCENE OF CAUVERY BASIN, INDIA Sanjay Kumar Mukhopadhyay

63

48. PALYNOLOGY AND DEPOSITIONAL ENVIRONMENT OF NINIYUR FORMATION (EARLY PALAEOCENE), CAUVERY BASIN, SOUTHERN INDIA M. R. Rao and J. Madhavaraju

65

49. CORALLINE ALGA SPOROLITHON FROM THE LATE PALAEOCENE LIPA BLACK SHALE FORMATION OF THE MITHAKHARI GROUP, MIDDLE ANDAMAN K. M. Wanjarwadkar and P. Kundal

66

50. HYDROCARBON SOURCE POTENTIAL AND DEPOSITIONAL CONDITIONS OF GURHA LIGNITE DEPOSITS (BIKANER BASIN), RAJASTHAN, WESTERN INDIA R. P. Mathews, Alpana Singh, S. Mahesh, V. P. Singh, B. D. Singh and Suryendu Dutta

67

51. RECOVERY OF A MARINE FOOD CHAIN FROM THE PALAEOCENE CARBONATE SEDIMENTS OF KARASUR FORMATION (PONDICHERRY AREA) OF CAUVERY BASIN Amit K. Ghosh, Abhijit Mazumder and Arindam Chakraborty

68

52. KEROGEN TREND ANALYSIS FOR DEPOSITIONAL ENVIRONMENT INTERPRETATION AND HYDROCARBON POTENTIAL OF SEDIMENTS FROM MATASUKH LIGNITE MINES, RAJASTHAN THROUGH PALYNOFACIES STUDIES Mahesh. S and Hukam Singh

69

xi

53. SIGNATURES OF PALEOGENE TECTONICS AND REVERSAL OF STRESS REGIME ALONG KACHCHH MAINLAND FAULT, KACHCHH, GUJARAT P.K. Singh

70

54. HYDROCARBON SOURCE ROCK OF THE KOPILI FORMATION (EOCENE), MEGHALAYA Y. Raghumani Singh, Guneshwor Tongbram and Akham Bijayalaxmi Devi

72

55. CHARACTERIZATION OF EOCENE LIGNITE DEPOSITS OF SAURASHTRA BASIN (GUJARAT): PETROGRAPHICAL AND GEOCHEMICAL PERSPECTIVES V.P. Singh, B.D. Singh, M.P. Singh, Alpana Singh, Suryendu Dutta

73

56. UNDERGROUND COAL GASIFICATION PROSPECTS OF PALEOGENE LIGNITE DEPOSITS OF BIKANER BASIN, RAJASTHAN Pramod Kumar Rajak and Vijay Kumar Singh

75

57. LATERAL VARIATIONS IN THE MOHO CHARACTER BENEATH THE EASTERN HIMALAYA Dipankar Saikia, M. Ravi Kumar, Dipankar Sarkar

76

58. LATE EOCENE (PRIABONIAN) AGE NANNOFOSSILS FROM REWAK FORMATION, GARO HILLS, MEGHALAYA, NORTHEASTERN INDIA Abha Singh, Jyotsana Rai and Rahul Garg

77

59. THRUST RELATED DEFORMATION PATTERN WITHIN THE PALEOGENE ROCKS ALONG THE MAIN BOUNDARY FAULT (MBF) AROUND DOL, HIMACHAL PRADESH, INDIA

79

Ram Jivan Singh, Digvijai Raj and Sachin Pachpor 60. LITHOSTRATIGRAPHIC UNITS OF SIWALIK BELT IN DARJEELING SUB-HIMALAYA VIS-A-VIS THEIR DEPOSITION DURING THE RISE OF HIMALAYA Amiya K. Huin, Naveen Kumar and Rajesh Kumar Yadav

80

61. A NOVEL APPROACH ON ESTIMATION OF CHEMICAL WEATHERING RATES FROM MARINE SEDIMENTS Nazia Khan and G. J. Chakrapani

81

xii

62. EVIDENCE OF MIOCENE MARINE TRANSGRESSION: A CASE STUDY FROM MOHULIA SEDIMENTARY BED, BARIPADA, MAYURBHANJ DISTRICT OF ORISSA Debapriya Adhikary and Sebabrata Das

83

63. EARLY CENOZOIC SEDIMENTARY SEQUENCES OF INDUS SUTURE ZONE, LADAKH HIMALAYA: PALEONTOLOGICAL CONSTRAINTS AND CORRELATION COMPLEXITY Sanjay Kumar Verma and Abhayanand Singh Maurya

84

64. PALYNOFLORAL, SEDIMENTARY ORGANIC MATTER CHARACTERISTICS AND ENVIRONMENT OF THE LIGNITE BEARING SUCCESSION AT SURKHA MINE, CAMBAY BASIN, GUJARAT: A CASE STUDY Priyanka Monga, Madhav Kumar, Vandana Prasad

86

65. CHAPATTIMYID RODENTS (MAMMALIA) FROM THE EARLY EOCENE BEDS OF SUBATHU FORMATION, NW SUB-HIMALAYA, INDIA: PALAEOBIOGEOGRAPHIC IMPLICATIONS Smita Gupta and Kishor Kumar

88

66. EARLY EOCENE FLORAL ASSEMBLAGE FROM CAMBAY SHALE (TARKESHWAR LIGNITE MINE), GUJARAT: PALAEOVEGETATIONAL, ECOLOGICAL AND ENVIRONMENTAL SIGNIFICANCE Hukam Singh and Mahesh Prasad

89

67. BIOSTRATIGRAPHICAL, PALAEOECOLOGICAL AND PALAEOBIOGEOGRAPHICAL SIGNIFICANCE OF VENERICARDIA LAMARCK 1801 SENSU LATO (BIVALVIA, CARDITIDAE) FROM THE PALEOGENE OF WESTERN INDIA Ipsita Ghosh and KalyanHalder

91

68. MARINE INFLUENCE DURING THE LATE CRETACEOUSPALAEOGENE IN PENINSULAR INDIA: PALAEOBOTANICAL EVIDENCE FROM THE DECCAN INTERTRAPPEANS R.S. Singh and M.F. Quamar

92

69. PALEODEPOSITIONAL ENVIRONMENTS AND PALEOBIOGEOGRAPHICAL IMPLICATIONS OF BIOTIC ASSEMBLAGES FROM THE CRETACEOUS-PALAEOGENE TRANSITION DECCAN INTERTRAPPEAN BEDS AT JHILMILI (DISTRICT CHHINDWARA), MADHYA PRADESH, INDIA Ashu Khosla

93

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70. GEOCHEMICAL INVESTIGATIONS OF PALAEOCENE-EOCENE JATHANG SEDIMENTARY SUCCESSION OF THE EAST KHASI HILLS: IMPLICATIONS TO LOW LATITUDE PETM EVENT Anupam Sharma

95

71. PALYNOLOGY OF THE AKRI LIGNITE MINE (EARLY EOCENE), WESTERN KUTCH, INDIA: BIOSTRATIGRAPHIC AND PALAEOENVIRONMENTAL IMPLICATIONS M. R. Rao, Rahul Garg, Poonam Verma and Sunil Bajpai

97

72. PALAEOCENE EVENTS AND FOSSIL RECORDS OF THE ANDAMAN ISLANDS Tarun Koley, Amitava Lahiri, K. M. Wanjarwadkar and Anju C. S.

98

73. PALEOGENE STRATIGRAPHIC RECORD OF INDIA: AN OVERVIEW D.S.N.Raju

99

74. PALEOPEDOLOGICAL EVIDENCES OF EARLY OLIGOCENE SEASONALITY IN FORELAND SEDIMENTS OF NW HIMALAYA Pankaj Srivastava, Subhra Patel, Khushboo

101

75. NATURE OF FLUID FLOW IN THE FORE-ARC BASIN OF HIMALAYA: A REVIEW Himanshu K. Sachan and Aditya Kharya

102

76. BIOSTRATIGRAPHY, PALAEOENVIRONMENT AND PALEOGEOGRAPHY OF PALAEOCENE SEDIMENTS OF CAUVERY BASIN, TAMIL NADU, SOUTH INDIA N. Malarkodi and V. Deepak

103

77. FLORAL DIVERSITY OF RAJASTHAN DURING PALAEOGENE: IMPLICATIONS TO PALAEOCLIMATE AND BIOSTRATIGRAPHY Jyoti Sharma

104

78. ANGIOSPERM FLORA OF DECCAN INTERTRAPPEAN BEDS OF INDIA AND THEIR BIOGEOGRAPHY Rashmi Srivastava

107

79. PALAEOGENE DHARAMSALA FORMATION; A POTENTIAL HOST FOR Uranium MINERALIZATION IN NORTHWEST HIMLAYAS Pradeep Pandey, G. B. Joshi, P.S. Parihar

108

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National Conference on Paleogene of the Indian Subcontinent

K-T BUNDARY ASTEROIDAL IMPACT, CRUST-MANTLE STRUCTURE AND GEODYNAMICS OF THE WESTERN CONTINENTAL MARGIN OF INDIA: GEOPHYSICAL PERSPECTIVE O. P. Pandey CSIR-National Geophysical Research Institute Uppal Road, Hyderabad-500007, India E-mail: om_pandey@ rediffmail.com

Late Cretaceous-Early Tertiary transition in India is marked by three major events of the earth’s history, Deccan volcanism, an asteroidal impact near offshore Mumbai and concurrent K-T boundary mass extinction, which led to demise of mighty dinosaurs. The K-T impact has now been confirmed through the experimental findings of Ir anomalies, high-pressure and temperature phase of fullerine in intertrappean sediments, besides shocked quartz and impact generated melts in the affected rocks. First two phenomena, together with India’s super mobility during 80 to 53 Ma, have resulted in large scale structural uplifts and total restructuring of the earth’s thermal field and underlying crust and mantle lithosphere beneath western continental margin and its environs, specially between latitude 16o and 24oN and longitude 70o and 75o E. Below this region, Moho is transitional and shallow (16-30 km), geothermal gradients often exceed 50o C/km, and heat flow on an average is about 56 to 97 mW/m2 in different geotectonic segments, with extremely upwarped asthenosphere (30-100 km). Heat flow input from the mantle is also very high due to rise of isotherms and mantle solidus. At some places, melting seems to have reached just below the Moho. In the process, about 100 to 150 km thick mantle lithosphere seems to have been removed from its bottom. Elevated temperatures apparently played an important role in maturing the hydrocarbons in oil-gas–rich Tertiary sediments. Besides thermo tectonic restructuring, K-T impact also led to (i) large scale emplacement of low density (~2.95-3.05 g/cm3) fractionated magma, generated during India’s super mobility to crustal and sub crustal depths, (ii) initiation of the Carlsberg ridge in the Indian ocean, (iii) break-up of Seychelles block from India’s west coast, (iv) formation of the Laxmi ridge in the northern Arabian Sea and (v) rejuvenation of concealed rifts like Koyna, Kurduvadi, Cambay and Kachchh. Consequently, K-T eventaffected Deccan volcanic region became seismically prone to damaging earthquakes. Interestingly, mafic crust has upwarped quite close to the surface with almost total erosion of granitic- gneissic upper crust from this region. We infer that the underlying mantle below these areas is less viscous, fertile and highly buoyant.

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GLOBAL PALEOGEOGRAPHY DURING K/T BOUNDARY AND PALEOGENE WITH SPECIAL REFERENCE TO THE INDIAN SUBCONTINENT Vinod C. Tewari Scientist G (Retd.), Wadia Institute of Himalayan Geology, Dehradun E- mail: [email protected]

Global paleogeographic changes across well developed successions of the Cretaceous– Tertiary Boundary and Plaeogene has been reconstructed using high resolution C - and O - isotope chemostratigraphy. Well known sequences from South America, Europe and India have been reviewed from the northern and southern hemispheres. The KTB sections at Stevns Klint, Gubbio, Neuquén Basin, Salta Basin, Paraiba Basin, Trieste Karst (Padriciano in northeastern Italy), Jhilmili intertrappean sediments in Central India, and Meghalaya (Mahadeo and Langpar Formations in Um Sohryngkew River section, Shillong plateau) in northeastern India have been discussed. All these crucial sections have been reviewed and correlated based on high resolution biostratigraphy and mass extinction, carbon-isotope chemostratigraphy, sedimentary microfacies analysis, paleoclimatic changes and major, trace and platinum group elements geochemistry. The KTB sections from Europe represent complete boundary sequences. In the Southern Hemisphere, Meghalaya in the Shillong Plateau is the only complete sequence which displays a well preserved KTB layer. In South America Bajada del Jagüel displays almost complete KTB layer. Recent results of occurrence of iridium anomaly, strong negative shift of δ13C values across the KTB, presence of micro-tektites at the top of a Maastrichtian breccia in an outcrop near Padriciano and Hg isotope from some sections have thrown new light on the cause of mass extinction at the KTB. The Um Sohryngkew section of Meghalaya is located in northeastern India, approximately 800–1000 km from the Deccan volcanic province in Central India and represents the most complete KTB marine sequence known from Indian subcontinent. It is correlatable globally with the most complete sequences. This section displays strong evidence of mass extinction well preserved KTB layer, stable isotope excursion and sea level change and can be correlated with the El Kef Global Strato-type Section and Point (GSSP) in Tunisia. The Um Sohryngkew section is well exposed in the Meghalaya, near Therria village, East Khasi Hills District, Shillong Plateau, northeastern India. The KTB in this section is characterized by a thin red clay layer enriched in Ir and other PGE with abundant subangular quartz grains. The Mahadeo Sandstone, just below the KTB, shows glauconite grains. The US section suggests a shallow marine coastal, estuarine and nearshore tidal flat depositional environment. The conformably overlying LangparLakadong Formations of Paleocene–Eocene age confirm shallow- marine shelfcarbonate ramp sedimentation. The northward movement of the Indian Plate during the Late Cretaceous- Paleogene period and the paleogeography of the southern and northern hemispheres with special reference to the Indian subcontinent is discussed in the light of the new data.

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ANALYSIS OF LONG WAVELENGTH GRAVITY DATA OVER K-T IMPACT STRUCTURE, OFFSHORE MUMBAI, INDIA Satyajit Dutta and NimishaVedanti National Geophysical Research Institute (CSIR) Uppal Road, Hyderabad-500007, India E-mail: [email protected]

The western offshore region of India forms one of the most anomalous regions of Indian subcontinent, which has been severely affected by Deccan volcanism caused either by K-T impact or interaction with Reunion plume. The impact structure, which is popularly known as Shiva crater, is situated at the center of this region (690-730 E longitude and 17.50-210 N latitude). A detailed analysis of long wavelength gravity field has been made to understand the deep crustal structure and evolutionary history of this region using findings from scaling spectral analysis. An average depth to the Moho at about 22±1 km is inferred in the region. However, in the central part of the impact crater, Moho is deeper at 26 km, possibly due to emplacement of 6-8 km thick magma body just above the Moho. Post impact sedimentary deposit is about 5 km thick in the region.

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ORGANIC MATTER FROM MARINE SEDIMENTS OF THE LATE CRETACEOUS-EARLY PALEOCENE UM-SOHRYNGKEW RIVER SUCCESSION, MEGHALAYA, INDIA: PALAEOENVIRONMENTAL INFERENCES AND K/PG TRANSITION Sucharita Pal1, J. P. Shrivastava1, Sanjay K. Mukhopadhyay2 and Sandeep Hamilton3 1

Department of Geology, University of Delhi, Delhi-110007 Ex-Geological Survey of India, Natural Energy Resources, Salt Lake, Kolkata 700091 3 Atomic Mineral Directorate for Exploration and Research, Hyderabad -5000 629 E-mail: [email protected]

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Combustion derived polycyclic aromatic hydrocarbon (PAH) based highresolution stratigraphic record across Cretaceous/Palaeogene boundary section of Um Sohryngkew River section is presented in the paper. 1 to 2 mm thick, yellowish brown organic rich clay layer in biozone CF3 is marked by sudden increase in the combustion derived high molecular weight PAH compounds (fluoranthene, pyrene, chrysene, benzo(a)anthracene) similar to those associated with the well established K/T boundary sections across the world. Additionally, low molecular weight - 3 (anthracene, fluorine) and 4 ring compounds also peak out in this layer. But, subordinate amount of low molecular weight 3 ring (phenanthrene, 3-methylphenanthrene, 2-methylphenanthrene, 9methylphenanthrene and 1-methylphenanthrene) PAH compounds also noticed in the successive layer of biozone CF2. High molecular weight PAH compounds found in biozone CF3 imply global fire induced by the heat supplied as a result of Abor or Deccan volcanisms, possibly linked with the K/T transition. PAH anomalies in biozone CF3 coincides with the well establishedCe anomaly layer, but, preceded by planktonic foraminiferal break and PGE anomaly bearing layer in the biozone P0. It is inferred that the K/T transition related global fire played significant role in the collapse of the ecosystem, causing sudden demise of organisms.

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DISCOVERY OF CALCAREOUS NANNOFOSSILS FROM DECCAN INTERTRAPPEAN BEDS NEAR MANAWAR, CENTRAL INDIA Jyotsana Rai, Vivesh V Kapur, Abha Singh, Sunil Bajpai and Shailesh Agrawal Birbal Sahni Institute of Palaeobotany, 53, University Road, Lucknow 226007 E-mail: [email protected]

We report here the discovery of calcareous nannofossils from a Deccan intertrappean section exposed along the Agra-Mumbai highway near Manawar town, Madhya Pradesh, central India. Very recently, a dominantly freshwater microfossil assemblage comprising of freshwater ostracods, charophytes, pulminate molluscs and fish scales along with a brackish water ostracode Neocyprideis raoi were reported from this locality (Kapur et al., 2014). The samples processed for nannofossils have yielded a rare, diminutive but datable assemblage of nannofossils. The recovered nannofossil assemblage is fairly overgrown but identifiable. The assemblage comprises Biantholithus sparsus, Discoaster mohleri, D. multiradiatus, Eprolithus octopetalus, Eprolithus sp., Ericsonia subpertusa, Fasciculithus tympaniformis, Laguncula pitchrensis, Sphenolithus primus along with abundant aberrant calcareous dinoflagellates. The occurrence of Discoaster spp. is somewhat surprising, as this taxon was hitherto not known prior to late Thanetian. The assemblage is broadly attributed to NP1-NP6 zones, indicating a Danian to early Thanetian age. The present discovery, seen together with an earlier record of Paleocene (P1a) planktic foraminifers from an inter-trappean section at Jhilmili (District Chindwara, Madhya Pradesh), supports the occurrence of marine incursions along the Narmada-Tapti lineament deep into the heart of Indian craton (Sharma and Khosla, 2009; Keller et al., 2009a, 2009b). References: 1. Kapur, V.V., Rai, J., Prakash, N. and Agrawal, S. (2015) Microfossil assemblage from a Late Cretaceous Intertrappean locality near Manawar, Madhya Pradesh, central India. In: International conference on “Current perspective and emerging issues in Gondwana evolution”, BSIP, Lucknow, February 19-20, 2015, pp. 42. 2. Keller, G., Adatte, T., Bajpai, S., Mohabey, D.M., Widdowson, M., Khosla, A., Sharma, R., Khosla, S.C., Gertsch, B., Fleitmann, D. and Sahni, A. (2009a) K-T transition in Deccan Traps and intertrappean beds in central India mark major marine seaway across India: Earth and Planetary Science Letters (282): 10–23. 3. Keller, G., Khosla, S.C., Sharma, R., Khosla, A., Bajpai, S. and Adatte, T. (2009b) Early Danianplanktic foraminifera from Cretaceous-Tertiary intertrappean beds at Jhilmili, Chhindwara district, Madhya Pradesh, India. Journal of Foraminiferal Research 39 (1): 40-55. 4. Sharma, R. and Khosla, A. (2009) Early Paleocene ostarcoda from the CretcaeousTertiary (K-T) deccan intertrappean sequence at Jhilmili, district Chhindwara, central India. Journal of the Paleontological Society of India 54(2): 197-208.

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ELASTIC PROPERTIES OF AMBENALI AND POLADPUR FORMATIONS OF DVP: NEW FINDINGS Nimisha Vedanti, Ajay Malkoti*, Satyajit Dutta, O.P. Pandey CSIR-National Geophysical Research Institute Uppal Road, Hyderabad-500007, India *E-mail: [email protected]

Physical properties and velocity measurements on 45 cores of Deccan basalt, recovered from Killari borehole KLR-1 provide a unique reference data set for Deccan Basalt from a seismically active region of Maharashtra, India. Killari borehole was drilled for geo-scientific investigations in the epicentral region of Killari earthquake. The borehole penetrated 338 m of Deccan flood basalts followed by a further 270 m of 2.57 Ga old Archean crystalline basement. The selected cores represent two important and less studied Formations named Ambenali and Poladpur of Deccan Volcanic Sequence. Detailed studies have been made on late Archean crystalline basement cores but hardly any studies have been made on volcanic cores. In this paper we report detailed petrophysical properties (density, P- and S- wave velocity) of selected Deccan basalt drilled cores. Travel times of P- and S-waves in the test samples were measured at 1.0 MHz frequency, using ultrasonic pulse transmission technique at NGRI. Preliminary investigations reveal that the petrophysical properties of basaltic lavas show significant variation in the Poladpur and Ambenali Formations of Deccan volcanic province. The Ambenali Formation is dominated by massive basalt samples, however, Poladpur Formation is dominated by vesicular porous basalt. In Ambenali, Vp and Vs velocity varies from 3.66 km/s to 6.49 km/s and 2.47 km/s to 3.69 km/s respectively. In comparison, the velocity range is 3.28 km/s to 6.23 km/s and 1.69 to 3.59 km/s respectively for Poladpur Formation. Seismic attenuation is high in vesicular basalt samples, which is an expected result but surprisingly very massive samples exhibited high attenuation especially for p-wave. Many samples have exhibited high density but low velocity, thus need to be further investigated in detail.

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PALEOGENE OF THE INDIAN PETROLIFEROUS BASINS: LARGER FORAMINIFERAL PROXIES AND ROLE IN HYDROCARBON EXPLORATION Sudhir Shukla Oil and Natural Gas Corporation, Dehradun E-mail: [email protected]; [email protected]

Paleogene System comprises three series viz. Paleocene, Eocene, and Oligocene heralding massive evolution of the new biota amongst animals and plants. These series are subdivided into nine stages by the International Sub-commission on Paleogene Stratigraphy (1989) and International Geological Congress, Washington (1992). Larger benthic foraminifera particularly the Nummulites have been so important in the development of Paleogene biostratigraphy, that the term Nummulitique was considered often synonymous to the Paleogene in the contemporary stratigraphic practices. British and French stratigraphers were traditionally the pioneers in the research related to the Nummulitique, both in the Indian and the European sedimentary basins. Paleocene Series was subdivided into Danian, Selandian and Thanetian stages, Eocene Series into Ypresian, Lutetian, Bartonian and Priabonian stages and the Oligocene Series into Rupelian and Chattian stages. Stratotypes of these stages along with several other stages were defined in the North Sea and Paris Basins during mid-19th/early-20th century. Paleocene / Eocene Thermal Maximum (PETM), is also one major research area marking transient period of global warmth (Around 55 Ma). Extensive carbonate deposition took place all along the western Indian continental shelf, major parts of the eastern continental shelf extending up to far north-east areas and the lesser Himalayan regions during Paleogene. In fact, the Paleogene in India is also characterised by extensive outcrops of massive carbonate and associated marl rich sediments (Western Indian Basins; South Shillong Shelf; lesser Himalayan belt), much of which is otherwise known from the sub-surface, through exploratory drilling. Indian petroliferous basins have been extremely prolific with in Paleogene sedimentary sections comprising carbonate and the clastic rocks and constitute major hydrocarbon reservoir, source and/or cap facies. In India, major producing basins have a brilliant history of fruitful hydrocarbon exploration and exploitation from the Paleogene formations and ONGC has been at the forefront of exploration and exploitation of such resources. In this process, ONGC has constantly kept pace with the developed countries in the absorption, application and development of frontier and emerging technologies. Commensurate to the changing exploration perspectives, geo-scientific quest for hydrocarbons has been based on conceptual and technological advances in core competencies. Continuous monitoring and analysis of data, retrived by drilling activities in various basins, is being analysed and

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integrated to improve the understanding of basin processes, macro-evolution and petroleum systems. The building of high resolution multimicrofossil biostratigraphy at reservoir scale, utilizing foraminifera, ostracoda, palynoflora and nannofossils, is the order of the day. Deciphering depositional environments, paleobathymetry, relative sea level changes and paleogeographic mapping are undertaken at basinal scale. Concept of sequence stratigraphic analysis is also helping prospect analysis, understanding of the depositional processes and basin evolution. Larger benthic foraminifera occurring in the Paleogene formations across different sedimentary basins on the western shelf of India are extremely helpful tools to assign sediment age, formation demarcation and biofacies, stratigraphic correlation, paleoecological analysis and paleobathymetric determinations. Planktic and larger foraminifera constitute the backbone of the industrial micropaleontology with a number of index species characterising each biozones because of rapid evolutionary changes and faster speciation, especially during the Paleogene system. Larger benthic foraminifera of the Indian Paleogene comprise diversified and complex foraminiferal assemblages belonging to several genera such as Nummulites, Assilina, Miscellanea, Lockhartia, Daviesina, Actinosiphon, Discocyclina, Pellatispira, Operculina etc. Several species amongst these genera have tremendous index value in high impact biostratigraphy and are characterized by their short geological ranges which could be utilized for intra and inter-regional stratigraphic correlations. Larger foraminiferal zonation based on the Shallow Benthic Zones (SBZ) was proposed by Shukla et al. (2005) for the Assam Shillong shelf on the lines of IGCP-286 and later input added to SBZ 1 to SBZ 23 covering entire Paleogene. Precise larger foraminifer biofacies during the Paleocene, Eocene and Oligocene have also been recognized in the sedimentary successions in different petroliferous basins across the Indian Shelf. This has facilitated local and regional biochronostratigraphy in conjunction with other geological and geophysical methods.

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PALEOGENE OF GUJARAT AND INDUSTRIAL GROWTH D. U. Vyas GMDC, Ahmedabad, Gujarat E-mail: [email protected]

After the diastrophic activity (late Cretaceous) and eruption of Deccan trap lava flows (Cretaceous–Eocene), the tertiary sedimentation commenced in Gujarat. Well developed tertiary sections are exposed in Kutch main land and in parts of Saurashtra, while a thick pile of tertiary sediments occupies the vast covered tracks falling in Cambay basin which produce substantial quantity of oil and gas. Palaeocene rocks and the associated carbonaceous clay indicate shallow water depositional environment. The Eocene rocks were followed by regressive phase and a transgressive phase represented respectively by Oligocene and Miocene rocks. The Eocene and Oligocene formations of Kutch, Saurashtra, South Gujarat and Cambay basin are potential source for various important minerals like lignite, bauxite, clays, marl, limestone, laterite, bentonitic clay, sandstone etc. Gujarat account for 34% of total production of lignite, mainly from Paleogene sequence. The mineral based industries in Kutch and South Gujarat based on limestone, lignite, bauxite, bentonite etc. are important for fuelling industrial growth of Gujarat. Soda ash and salt based industries and cement industries are based on Paleogeneage resources of Kutch area. A 490 MW Thermal Power Station based on lignite is bestowed due to lignite formations in Paleogene of Kutch. Gujarat has access to global market and Indian hinterland, robust infrastructure, private participation, value addition, human resources development, e-governance etc. provides business friendly environment in the state. Overall, mineral based industries growth in Gujarat is based mainly on the Paleogene of Kutch, Saurashtra and Cambay basin and South Gujarat.

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THE TERTIARY PETROLEUM SYSTEM OF NORTHWEST HIMALAYA: CHALLENGES IN EXPLORATION Manoj Kumar Baruah Frontier Basin, ONGC, Dehradun E-mail: [email protected]

Exploration for hydrocarbons in the Northwest Himalayan Foothills has been continuing for more than six decades, without notable success. The envisaged petroleum system in this sector of the Himalayan Fold Thrust Belt is Tertiary in age, with the Eocene Subathus being the source and the Oligocene-Miocene Kasauli-Dagshai (Dharamsalas) and Miocene-Pliocene Siwaliks being the reservoir rocks. Thick shale units in the sequence (especially towards the lower part) and interbedded shale units of regional extent are the probable cap-rocks. Being part of a folded belt, structural hydrocarbon traps are more likely than stratigraphic traps although the latter are not ruled out. The commercial occurrence of hydrocarbons in neighbouring Pakistan just west of the Northwest Indian Himalaya raises possibility of striking oil/gas in this area also and acts as a major motivational factor driving the exploration fraternity in India. However, in spite of an aggressive and optimistic exploration campaign, success has eluded us thus far. So what ails exploration for hydrocarbons in the Tertiaries of Northwest Himalaya in the Indian sub-continent? This paper discusses the various facets of challenges faced by the explorationist whilst venturing into the Himalayan Foothills and advocates methods of integrating and analyzing different available datasets using modern concepts and technologies to come up with a much better and more constrained geological model for exploration that may yield a conclusive result, irrespective of whether it is positive or not.

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PALYNOFACIES ANALYSIS AND HYDROCARBON SOURCE ROCK POTENTIAL OF BARSINGSAR LIGNITES, BIKANER DISTRICT, WESTERN RAJASTHAN, INDIA Sikander, O.P. Thakur and N.N. Dogra Department of Geology, Kurukshetra University, Kurukshetra E-mail: [email protected]

The present paper deals with palynofacies analysis of lignites from Palana Formation at Barsingsar Lignite Mine in Bikaner, Rajasthan. The Palana Formation at Barsingsar contains thick lignite horizons interbedded with carbonaceous clays. Lignite Samples were treated with conventional techniques by using HCl and HF. The Nitric acid treatment was avoided to get unoxidised residue. The quantitative estimation of organic matter was made by visual estimation under transmitted light microscope. The overall dominance of the organic matter in the Barsingsar section is shown by structured terrestrial organic matter followed by Black organic matter and Biodegraded terrestrial organic matter, which suggest partial oxidizing conditions prevailing in the Basin during its deposition. Adequate amount of Resin in the samples is indicative of marginal marine environment for its deposition. Abundance of grey amorphous organic matter in some of the samples in the section reflects deposition under reducing conditions and cyclicity of the terrestrial and amorphous organic matter suggests fluctuations from shallow to short lived deep water conditions in the Basin. The present study shows the dominance of humic facies which favors good gaseous hydrocarbon potential for the Barsingsar lignites of Palana Formation.

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APPLICATION OF DEPOSITIONAL ENVIRONMENTAL MODELLING AS A TOOL TO LIGNITE EXPLORATION: A CASE STUDY FROM NORTH-WEST PALANA BASIN, JAISALMER AND BIKANER DISTRICTS, RAJASTHAN Rajuram Saraswat, Bijoy Ashish Sen, Mohammed Ahmed and Shivaji Gupta Geological Survey of India, Western Region, Jaipur E-mail: [email protected]

The Palana basin is a linear E-W trending basin, approximately 200 km long and 50 km wide and is bounded by Delhi-Lahore-Sargodha ridge in the north and PokhranNachna high towards south. The Aravalli range broadly defines its eastern boundary whereas in the west the extension of the basin is under thick cover and possibly continues up to the Suleiman range of Pakistan. The occurrence of economic Lignite and carbonaceous matter is confined to the Paleogene sedimentary sequences of western Rajasthan. The complex basinal lithological set up, irregular disposition and lensoid nature of lignite seams without any marker horizons act as major hindrances in framing of a composite exploration strategy. Planning for exploration of lignite in the area necessitates an understanding of the intricacies of the development of the sedimentary basin through the interpretation of available subsurface data generated in the course of exploration by drilling. Exploration carried out so far in the Palana peri-cratonic basin indicates that the lignite occurrences have limited aerial extent, irregular disposition and variable thickness of individual seams. Considering the variation in litho packages, basin tectonics and sedimentation history, a conceptualised model of deposition including aspects of basin geometry as well as behaviour of the host lithology for lignite in conjunction with emphasis on basin development and depositional environment have been attempted. This has lead to understanding the geological setup of the Paleogene sequence of the study area located in the north-western part of the Palana basin and helped in formulating future exploration strategy of the complex and irregular lignite deposits. Analysis of the information generated essentially through drilling has been applied for evolving the model and the present hypothesis has been fine tuned by applying these conclusions in new areas with progressive success. The lignite occurrences of the area are correlatable to the established worldwide marine cycles. Paleogene sedimentation in the Palana-Nagaur basin commences with lignite bearing Palana Formation under subtropical swampy environment on the continental as well as near shore parts over the basement of Proterozoic Nagaur Formation. Subsurface data from the study area boreholes in the north-western part of Rajasthan suggest that the Palana and Marh formations are coeval in nature with Palana Formation being deposited in the transitional part with evidences of marine incursion as evidenced from the documentation of fossiliferous horizons, while deposition of Marh Formation occurred towards the continental side of the basin. The overlying Jogira Formation is correlatable to the Eocene marine transgression. Absence of lithologies of lignite bearing Palana Formation in the central part of the study area has been used as an important tool in planning for exploration.

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ORGANIC PETROLOGY OF PALEOGENE COAL DEPOSITS OF GARO HILLS, MEGHALAYA, INDIA Alok K. Singh Rajiv Gandhi Institute of Petroleum Technology, Ratapur Chowk, Rae Bareli, India Email: [email protected]

The Paleogene coal deposits of Meghalaya occur in the Garo Hills, Khasi Hills and Jaintia Hill district of Meghalaya. The Garo Hills coalfield are the most productive where coal seams were formed over platform areas under stable shelf condition. The coalfields of Garo Hills are located along the south-western extremity of Shillong plateau. The coal deposits of Garo Hills have been divided into six coalfields such as East Daranggiri, West Daranggiri, BaphaklramPendengra coalfield, Siju Coalfield, Baljong, Dofrengg and Hanspel coalfield and Rongrenggiri coalfield. However, the mining activity is confined only to the West Daranggiri and Siju coalfields. Only Daranggiri Seam of West Daranggirri and Siju Top Seam of Siju coalfield has attained a workable thickness. The Tura Formation, which contain coal deposits of Meghalaya, is classified into Lakadong sandstone (25 m to 250 m thick), overlain by Umlatdoh limestone (70 m to 110 m thick) and rest over Lakadong limestone (25 m to 60 m in thickness). In order to carryout petrographic characterization and to reconstruct the paleodepositional conditions, the pillar coal samples from workable coal seams were collected from all the three major coalfields. The quantitative maceral and microlithotype analysis in ordinary light and blue irradiation, and reflectance measurement were performed using refined microscopic techniques and advanced petrological microscope aided with MSP 200 photometer. The result shows that the main petrographic components are vitrinite, inertinite, and exinite minerals. The quantitative data suggest that these coals are vitrinite rich with poor concentration of inertinite and appreciable amount of exinite group of macerals. According to microlithotype concentration these coals may be characterized as vitrinite rich and minor amounts of clarite, vitrinertite and durite. The dominant minerals are clays, siderite and pyrite. Based on the petrological evidences, the evolution of Garo Hills coals has been discussed. The petrographic character and presence of teleutospore suggest that Meghalayan coals are similar.

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FORCING FACTORS FOR THE LATE PALEOCENE (57.9-54.7 MA) TRANSGRESSION AND LATEST MIDDLE EOCENE (41. 3-38.0 MA) REGRESSION ON THE INDIAN SUBCONTINENT B. P. Singh1, Y. Raghumani Singh2, D. S. Andotra3, A. Patra1, V. K. Srivastava1, Venus Guruaribam2 , Umarani Sijagurumayum2 and G. P. Singh4 1

Centre of Advanced Study in Geology, Banaras Hindu University, Varanasi-221005, India 2 Department of Earth Sciences, Manipur University, Imphal, Manipur, India 3 Directorate of Geology and Mining, Jammu & Kashmir State, Jammu-180006, India 4 Department of Geology, Gombe State University, Gombe, Nigeria Email: [email protected]

Cenozoic Era was the turning point in the geological history of the Indian subcontinent when India experienced maximum isolation before it collided with Asia and there occurred a great mountain building activity shaping the Himalaya. In the Cenozoic era, the sedimentation commenced in the Late Paleocene (~57.9 Ma) in the pericratonic basins of the western India as well as the foreland basins of the Himalaya that marks the beginning of a major transgression on the Indian subcontinent. Till now, it is not sure whether this transgression was forced by tectonics or climate. We have interpreted that the primary driver for this transgression was the Asian tectonics that marks the beginning of the India-Asia convergence. A major regression of similar magnitude occurred during latest middle Eocene (41.3-38.0 Ma) that corresponds to global sealevel fall. This regression is global and can be identified even in the Cenozoic basins developed within the African plate. It is interpreted that this regression was driven by the global cooling during latest middle Eocene/late Eocene, possibly associated with the nucleation of the Antarctica ice-sheets coupled with the uplift of the Himalaya.

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PALEOGENE BASIN FORMING AND MODIFYING TECTONICS AS REVEALED IN SEISMIC SECTIONS OF ARABIAN SEA AND BAY OF BENGAL K.S. Misra Department of Petroleum Engineering and Earth Sciences University of Petroleum and Energy Studies, Dehradun E-mail: [email protected]

High resolution seismic data processed by Pre-Stacking and Depth Migration (PSDM) and Pre-Stacking and Time Migration (PSTM) processing techniques, have made on eloquent exposition of basin forming and modifying tectonics in oceanic regions around peninsular India. The Cretaceous –Tertiary (K-T) boundary in these regions is characterized by extensional tectonics, subsidence along nearly vertical faults, formation of basins, decompression melting and outpouring of enormous lava units, which are interlayered with Cretaceous sediments. This volcano-sedimentary sequence continues in entire Bay of Bengal and eastern half of the Arabian Sea. It also forms technical basement for the deposition of uninterrupted Paleogene succession. Processing by PSDM and PSTM techniques have made it possible to get information below the volcanics. Several basins with thick Mesozoic succession have been identified. Furthermore, these processing techniques have also improved the resolution, due to which litho-units of Paleogene sequence could be identified. These litho-units have various proportions of limestone, shale and sandstone and are some of the finest source rocks for hydrocarbons around peninsular India. Extensional tectonics with few pulses of compression has deformed the entire succession. However, the Mesozoic rocks are more severely deformed mainly by nearly vertical faults. The effect of these faults progressively diminishes in overlying younger Paleogene and Neogene rocks. Most of these faults show upward or downward convergence, intersecting each other in the Oligocene stratigraphic horizons, thus forming an hour-glass structure. The basal portion of these structures is occupied by several oceanic ridges. Geological evidences suggest that they have cropped up all along their length during terminal part of Cretaceous period and have influenced the deposition of Paleogene succession. These ridges meander gradually in the northern part and curve towards west in the southern part. Prolific growth of coral reef complexes is also observed on volcanic platform, where gradual subsidence of certain blocks is ascertained. The tectonic grain of these ocean basins is defined by elongated basins and ridges which have also originated at K-T boundary. These sheltered basins were most appropriate sites for deposition of sediments rich in good quality organic matter, as source rock for hydrocarbon generation. The wedge-outs on both side of oceanic ridge and the coral reef complexes capping these ridges could be explored for preferential accumulation of hydrocarbons.

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A COMPARATIVE STUDY OF THE DEFORMATION PATTERN AND SEDIMENTATION HISTORY OF THE SUB-HIMALAYAN LOWER CENOZOIC SUCCESSION OF JAMMU AND HIMACHAL PRADESH: THE TECTONIC IMPLICATIONS Prabir Dasgupta1, Gautam Ghosh2 and Sumit Dey2 1

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Department of Geology, Durgapur Government College, Durgapur 713214 Department of Geology, Presidency University, 86/1 College Street, Kolkata 700073 E-mail: [email protected]

The evolution of frontal fold-thrust belts (FTBs) containing foreland-vergent imbricate thrust systems and their spatial variations along the length of the orogenic front has been a major focus of research for understanding the dynamics of mountain belts in collisional settings. The kinematic evolution of the frontal FTB in NW Himalayas that incorporates the lower Cenozoic sedimentary succession comprising the Subathu, Dagshai and Kasauli formations belonging to the sub-Himalayan zone (SHZ), however, received much less attention compared to the more deformed orogenic interiors. These sediments developed in a foreland moat in course of continuous suturing of India and Eurasia and provide opportunity to study the sedimentation pattern in the light of the progressive evolution of the basin, the chronology of India-Eurasia collision, uplift and exhumation of the orogenic front. Difference in pattern of disposition, basin-fill succession and the deformation history of the sub-Himalayan lower Cenozoic Subathu Formation of Himachal Pradesh and Jammu throws some new light on the India-Eurasia collision, the initial chapter of the Himalayan orogeny. The Subathu succession in Himachal Pradesh is disposed in several thrust sheets bounded by regional thrusts and their splays showing all the characters of a typical foreland FTB. In contrast, the Subathu succession exposed over a vast area in Rajauri district of Jammu & Kashmir is significantly less deformed with the development of antiforms at tips of blind thrusts that reaches the present erosional surface at a few places breaching the fold structures. The apparently continuous Subathu succession here starts with a basal chert breccia resting unconformably on the Proterozoic Sirban Limestone. This basal breccia is followed upward successively by coastal sandstone and pyritiferous black shale with coal. The rest part of the succession, represented by bioclastic limestone, shale and siltstone indicating alternation of open and confined situation, points to a coastal lagoonal condition of deposition. The palinspastically restored succession in Shimla hill reveals that the Subathu Formation does not differ much from its counterpart in Jammu except the presence of a turbidite succession at the lower part representing an event of syndepositional tectonic disturbance. The Subathu Formation here starts with pyritiferous black shale with peat. Evidence of this euxinic condition at the basal part of Subathu Formation from Jammu to Himachal Pradesh is consistent with the occurrences of Tertiary coal and lignite in small pockets along the margin of the Indian plate, possibly indicating marine transgression in 16


consequence of squeezing of Tethys prior to India-Eurasia collision. In the northern margin of the Indian plate this transgressive phase continued till the closing of the Tethys. The reconstructed succession further reveals that in Shimla hills the Subathu Formation is unconformably overlain by Dagshai Formation while in Jammu it passes conformably on to the overlying Murree Formation. In Jammu area the Subathu succession is presently exposed along the southwestern slope of the basement ridge of Sirban Limestone and the repository gradually extends across the basement ridges towards the northeast with the record of younger sedimentation. Since Tethys was situated to the north of the Indian plate, the transitional environment was expected to develop on the same side of the continental block. The observed mismatch could be explained by an initial collisional framework where the Indian plate proceeded towards the Eurasian plate keeping its present southwestern side towards northwest, and underwent a subsequent anticlockwise rotation. The plate margin towards the west of the pivot as a result shows an opposite pattern of disposition of the Cenozoic succession compared to the eastern side. The higher rate of shortening observed from the eastern part compared to the west could also be a result of such rotation. This finding thus substantiates the diachronous model of India-Eurasia collision with a significant component of anticlockwise rotation following initial collision.

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PALAEOGENE–NEOGENE TECTONICS AND CONTINENTAL AGGRADATIONAL BASINS IN NORTH-WESTERN INDIA– IMPLICATIONS FOR GEOLOGICAL EVOLUTION OF THAR DESERT Sudesh Kumar Wadhawan D-159, Malviya Nagar, Jaipur-302 017, India E-mail: [email protected]

Thar Desert is characterised by arid-semiarid ecologically fragile environment and occupies a unique tectonic-sedimentary domain in north-western (NW) India. It is confined essentially to West Rajasthan Shelf (WRS). The tectonic disposition and basement configuration of intra-cratonic basins and sedimentary formations here range from the Precambrian Delhi Supergroup in the east, Late Proterozoic to Early Palaeozoic Marwar Supergroup of sedimentary rocks in the middle, to Mesozoic and Cenozoic cover sedimentary formations on the western and north-western fringe areas in western parts of Rajasthan and Haryana in north-western India. It is remarkable that successive geological young age of sedimentary formations is mapped from the Aravalli Hill ranges on the east to the sand covered rocky plains on the west in the Thar Desert. Distinctive geomorphic expressions and relative lowering of relief are also deciphered and recorded in an eastwest transect along northern parts of the Thar Desert. Palaeogene rocks in the Jaisalmer Basin of western India are represented by sandstone-shale sequence of the Sanu Formation. These are capped at places by sandclay/ bauxitic clays and pisolitic laterite. These in turn are overlain by the fossiliferous limestone-bentonitic clays and fullers’ earth sequence of the Khuiala Formation (Lower Eocene) and the younger limestone-shale succession of Bandah Formation (Lower to Middle Eocene). Calcretised gritty conglomerates, ill-sorted and indurate pebblygravelly, ferruginous sandy and clayey fluvial deposits in the area are categorised as the Shumar Formation of Neogene (Plio-Pleistocene) / basal Quaternary age. Geological mapping of Palaeogene - Neogene formations in NW India have helped reconstruction of the palaeo-geographic shore-line limits of the Tertiary sea. Such inferred basement disposition ostensibly had a bearing on the source of evaporate minerals and continuing salinity aspects of the present day inland lakes and playas in the region. Successive deepening of the sedimentation basin is also inferred from the geological logs prepared during the drilling probes for the Potash Mineral Investigation by Geological Survey of India in NW India. It has been postulated that the NE-SW trending Aravalli hill ranges were rejuvenated as a horst bounded by the Great Boundary Fault (GBF) in the east and well known Sardarshahar Fault (west of Churu) and a series of westerly down-thrown step faults (called Manpia Faults) on the west thus segmenting the Thar Desert in northwestern Rajasthan into several Neogene depressions or the depocenters in-filled with 18


Quaternary continental aggradational deposits of fluvio-lacustrine and aeolian origin. Based on geological field surveys, interpretation of sub-surface data and dug-well inventory, it has been feasible to delineate a series of linear stepped grabben structures hosting a succession of Quaternary deposits separated respectively by denudational relief features. Their stratigraphic succession is established and correlated to build-up a model for improved geological understanding. Present contribution attempts to elucidate role of Palaeogene – Neogene tectonics and the inferred palaeoclimatic changes on the geological evolution of Thar Desert in NW India.

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PALEOGENE TECTONIC AND SEDIMENTATION RECORDS OF THE ANDAMAN-NICOBAR ACCRETIONARY RIDGE P. C. Bandopadhyay DST-Project, Department of Geology, University of Calcutta, Kolkata E-mail: [email protected]

The Andaman-Nicobar Archipelago in the North-East Indian Ocean is a convergent margin accretionary island arc (outer arc ridge). It provides a rare opportunity to observe and study the rocks formed in subduction setting and to understand the tectonic, volcanic and sedimentary processes at Paleogene plate margin. The PalaeoceneEocene Mithakhari Group and Oligocene sandstone turbidites (Andaman Flysch) records an evolving Paleogene history of tectonics, volcanism and sedimentation for this island arc. Ungraded to poorly graded matrix-rich, polymictic conglomerates, gritty to finegrained volcaniclastic sandstones, interbedded mudstones and fossiliferous limestones are major lithologies of the Mithakhari Group. Palaeontological studies carried out in Limestone suggest a Late Paleocene-Eocene depositional age for the Mithakhari Group. Intervals of shale pebble conglomerates and trace fossils indicate a shallow water depositional setting. Outcrops of interbedded sandstone-shale show coherent (bedded) and chaotic units. Sheared and fractured blocks and phacoids of sandstones embedded in scaly, foliated mudstone in chaotic unit are ideal example of ‘blocks in matrix’ fabric characteristic of the melanges of subduction zone accretionary complexes. Volcanic-lithic rich to lithic-poor quartzo-feldspathic Mithakhari sandstones are inferred to have been derived from dissected arc massif and accreted ophiolite. Deposited between 30 and 20 Ma, the Andaman Flysch, devoid of ichnotraces and contains reworked body fossils, is a deep water siliciclastic turbidite composed of quartzofeldspathic to feldspatho-lithic metamorphiclastics quartzwacke sandstones. Laterally persistent, parallel-sided, meter thick and fine-grained sandstonesbeds interbedded with laminated shale in Andaman Flysch, show complete and partial Bouma sequences. Flute casts at the base of the sandstone beds and framework composition indicate sediment transport from the north and northeast province may be the western Burma. The Mithakhari rocks were deposited when there was an active subduction, accretion and arc magmatism punctuated by intervals of tectonic quiescence facilitated carbonate deposition. Andaman Flysch, on contrary, was deposited during a time when there was a little or no arc magmatism, a significant uplift and erosion of the continental meta-sedimentary terrane, triggering enhanced supply of terrigeneous clastic sediments. Thus, a change in the style of tectonism and volcanism during the Paleogene is imperative. This enhanced weathering from an uplifted terrain and a significant supply of siliciclastics to a deep sea fan might have been associated with early Oligocene global glaciations and drop of sea level in the order of 140m at 30 Ma that must have been driven by tectonic forces (Curray and Allen, 2008). The Andaman flysch represents 20


basinal scale deposition in submarine fan on an open ocean floor, while the Mithakhari Group was deposited in small and shallow water, fault-controlled slope basins formed on an accretionary complex, before being accreted to form an outer arc ridge. Cenozoic paleogeography of the Southeast Asia (Hall, 2012) reveals that the Andaman Sea did not exist prior to mid Miocene and the position of A & N Islands during the Paleogene was closer to continental margin, west of the Burma-MalayaSumatra peninsula. Historical records described that the Andaman Nicobar islands were close to littoral states of Burma. Sewell (1925) suggested that the Andaman–Nicobar Ridge had drifted toward the west away from the South-East Asian mainland, and had thus formed a pronounced curve with its apex in the region of ‘Little Andaman’ Island. Abundant andesitic juvenile sand grains in Mithakhari sandstones indicate presence of arc massif with andesite volcano at the top, possibly existed on the western margin of the Malaya Peninsula forming part of the overriding Eurasia plate. Mitchell stated the existence of Cretaceous-Eocene volcanic arc stretching from the Himalaya through Myanmar to Sumatra.

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ICHNOLOGY OF A PALEOGENE FLUVIAL MEANDERING CHANNEL-LEVEE COMPLEX: MOHAMAD KI DHANI SANDSTONE, JAISALMER BASIN, INDIA Bhawanisingh G. Desai School of Petroleum Technology, Pandit Deendayal Petroleum University, Raisan Village, Gandhinagar-382007 E-mail: [email protected]

Ichnological signatures are regarded as storehouses of pristine information regarding the Paleo-depositional environments and palaeoecological reconstruction. Such stored information becomes more significant, in situations where there is lack of other proxy like body fossils for reconstructing paleo-environment and palaeoecological conditions. The Paleogene in Jaisalmer basin is represented by a fluvial succession belonging to Mohamad-ki-dhani sandstone member of Sanu Formaiton. In the outcrop, the succession is sandstone dominated characterize by fine to medium grained argillaceous sandstones that shows fining up sequence. The present study explores several sections that expose continuous succession from lower part of the Mohamad-kidhani sandstone member to the overlying Early Eocene marine succession of shalelimestone alterations belonging to lower part of Khuiala Formation. The studied Paleogene succession shows two well-developed cycles of fining upward sequence interpreted as meandering channel system topped by laminated siltstones belonging to levee plain. Channel sands are strongly bioturbated with presence of Egadiradixusrecti brachiatus, which are vertical tapering down root network. In contrast, the levee sediments shows well preserved trace fossils like Arenicolitesi sp, Skolithos linearis, Camborygma eumekenomos. The Ichnofabric analysis reveals that the levee sediment shows cross cutting and tiering of two distinct trace fossil community, one dominated by soft sediment like Arenicolites and Skolithos while other dominated by deep tiered, firm ground trace fossil like C. eumekenomos. Thus, paper will discuss the potential of using Ichnofabric analysis in understanding non-marine paleoecology and paleodepositioanl control.

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STUDY OF BIOEROSION AND ENCRUSTATION FROM THE MIDDLE EOCENE OF KUTCH, GUJARAT AND ITS BEARING ON BASIN EVOLUTION Sayoni Mitra Das1 and Kalyan Halder2 1

Gemmology Division, Central Headquarters, Geological Survey of India, 15, A & B, Kyd Street, Kolkata, 700 016 2 Department of Geology, Presidency University, 86/1, College Street, Kolkata, 700 073 E-mail: [email protected]; [email protected]

Bioerosion and epibiont attachment on bivalves have been studied from the Middle Eocene Harudi Formation and the Fulra Limestone Formation of Kutch, India. The Harudi Formation, composed of argillaceous deposits with occasional marl beds, was deposited at a relatively restricted environment in a transgressive systems tract, whereas, the Fulra Limestone is made up of foraminiferal limestone indicating open marine basinal condition. The present study involves bivalves from the Harudi Formation and the basal part of Fulra Limestone. Informal biostratigraphic classification of the studied section has been done based on the distribution of the bivalves. The divisions, in ascending order, are: Caestocorbulagujaratensis-Bicorbulakutchensis bed, Flemingostreapseudoflemingi bed, “Gryphaeostrealakhpatensis” bed, and Pyncondontekachchhensisbed. The well known“Nummulitesobtusus” band occurs between units 2 and 3 having certain overlapping with the Flemingostreapseudoflemingi bed. The basal unit, a molluscan shell bed with multitudes of fossils dominated by infaunal bivalves in random orientation and high matrix content, is a storm generated unit. Good preservation, especially bivalves often in articulated condition, indicates autochthonous to parautochthonous provenance. The overlying Flemingostreapseudoflemingi bed is an oyster bank. This and the “N. obtusus” band provided hard substrate for epibenthic organisms and modified the nature of substrate for some time. In the upper two units fine sediment substrate resumed, where grypheoid oysters dominated. The study revealed that bioerosion and encrustation are low on the infaunal bivalves from the basal shell bed whereas the same are extremely high on epifaunal bivalves coming from all the upper 3 beds. This indicates that the dead shells of oysters were retained on sediment water interface for long whereas infaunal bivalves from the basal unit were buried rapidly. Hence, the rate of sedimentation was quite low in the studied interval with sudden surges of storm in the early part of deposition at the Harudi Formation. Further, the study shows that Oichnusspp. and Entobiaspp. are the most abundant traces on the dead shells of bivalves. Encrustation by spongesis generally believed to be responsible for the development of Entobia, whereas the origin of Oichnus is equivocal. Body fossils of sponges are not known from the area of investigation and have not been encountered in field in spite of the presence of numerous Entobia. So the study provides a more comprehensive idea about the biodiversity present in the basin during the Middle Eocene. 23


PALEOGENE SEDIMENTATION IN PARTS OF KOHIMA SYNCLINORIUM, NAGALAND, INDIA: CHANGES TROUGH TIME S. K. Srivastava and A. Moalong Kichu Department of Geology, Nagaland University, Kohima Campus, Meriema Kohima-797004, Nagaland E-mail: [email protected]

The Naga Hills, a part of Indo-Burman Range (IBR), is the result of IndoBurmese collision events where huge quantities of sediments have been deposited in Assam-Arakan basin. The complicated tectonic framework of this part of Indian continent controls the depositional system as both palaeogeography and provenance had changed through time. However, it suffers from over simplifications. Tectonostratigraphically, Nagaland can be divided in five NE-SW trending linear zones from east to west into Naga Metamorphics, Ophiolites, Volcaniclastics, Inner Fold Belt and Belt of Schuppen. The Inner Fold Belt (IBF) is occupied by two synclinoria; Patkai Synclinorium in the north and Kohima Synclinorium in the south. Palaeogene sediments exposed in parts of Kohima Synclinorium, a part of which forms the present study, comprise argillaceous lithounits of Disang Group which grades into Barail Group of areneceous composition through a mixed shale-silt-sand lithologies which do not match either with Disang or Barail Group of rocks. The term Disang-Barail Transitional Sequences (DBTS) has been introduced to denote such lithologies within Kohima Synclinorium. DBTS is well exposed towards northwest of Kohima town. Similar lithologies are also exposed in the south of Kohima town. Disang Group of rocks are exposed in the north of Kohima whereas multi-storied areneceous rocks of Barail Group are exposed in the south of the synclinorium. This un-interrupted sedimentation is attributed to plate interaction in the east and continuous supply of sediments during Palaeogene period. The present work aims at attempting to interpret the sedimentation pattern and its relationship with dichronous nature of plate interactions and changing source and depot-centres.

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PALEOGENE OF THE LESSER HIMALAYA: A REVIEW OF CONTROVERSIES O. N. Bhargava INSA Honorary Scientist 103, Sector 7, Panchkula-134109 E-mail: [email protected]

The Paleogene in the Lesser Himalaya of the western sector is represented by the Subathu and Dagshai formations, which constitute part of the Sirmur Group. Several aspects of these two formations are enmeshed in controversies listed as below: 1. Nomenclature: The Subathu Formation has also been termed as the Nummulitics, whereas the Dagshai Formation is also described as the Lower Murree and also as the Lower Dharamsala in Kangra area of Himachal Pradesh. The terms Murree and Dharamsala have been also used for the Kasauli Formation with the prefix of "Upper". 2. Stratigraphic relationship: Originally, the Subathu and the Dagshai formations were considered conformable. The paleomagnetic data also support a continuous succession. However, the Bugti Beds (now in Pakistan), equated with the Dagshai Formation, yielded vertebrate fauna that was considered to represent an early Miocene age (Burdigalian). Since the youngest fossil in the Subathu Formation is of Middle Eocene age (Lutetian), an unconformity was propounded between the Subathu and the Dagshai formations to account for the absence of the Oligocene element. Recently, the vertebrate fauna of the Bugti Beds has been assigned an Oligocene age. Notwithstanding the lithological and biochronological continuity, based on the occurrence of detrital zircons, a break of ~10 My is advocated between these two formations. There is still another controversial dimension to the stratigraphic relationship of the Subathu and Dagshai formations. The Dagshai Formation, conventionally recognised younger than the Subathu Formation, is also interpreted as time equivalent and 'red facies' variant of the Subathu Formation. In Nepal, a ferricrete horizon intervenes between the Bhainskati (=Subathu) and the Dumri (=Dagshai) formations, signifying a sedimentological break. In the Sulaiman Range a continuous Paleogene sequence is observed, while in the Salt Range and Kohat reworked Eocene fossils are recorded in the Upper Murree (Burdigalian) sequence, in the Potwar area a sequence equivalent to the upper part of the Dagshai Formation rests over the Chorgali Formation (= part of the Subathu). 3. Sedimentological aspects: Most workers interpret the Subathu Formation as a shallow marine sequence and the Dagshai-- a deltaic-estuarine deposit. Recently, the Subathu has been considered a flysch sequence, in which shallow marine fossils are regarded to have been derived from the shallower parts located towards the craton. 4. Structural setup: The spatial repetition of the Subathu and the Dagshai formations is considered due to overturned folds, with sheared overturned limb. Recent drilling by the ONGC suggests a multi-layered decollement. 5. Balanced sections: Three balance sections are available for the Paleogene stretch.

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DISTRIBUTION OF TERTIARY SUCCESSION IN NEPAL LESSER HIMALAYA Megh Raj Dhital Central Department of Geology Tribhuvan University, Kirtipur, Kathmandu, Nepal E-mail: [email protected]

Tertiary rocks play a vital role in unravelling the tectonic history of the Himalaya. In the Northwest Himalaya of Simla area, the Tertiary succession exhibits a dual facies– a lower marine sequence and an upper freshwater and sub-aerial succession (Wadia, 1957). The exact horizon where the change from marine conditions to freshwater takes place cannot be located with certainty, but everywhere the Eocene is marine. In the Krol Belt, Auden (1934) described the Lesser Himalayan Tertiary rocks under the Subathus (olive-green and purple oily-looking shales, green and white sandstones, iron-stained quartzites, and shelly limestones), Dagshais (alternations of purple, cindery, sandy shales, and purple or green sandstones), and Kasaulis (made up of hard and massive grey-green sandstones with subordinate green, soft shales). In the north belt of the inner Lesser Himalaya of far-west Nepal, about a few hundred metres north of Malikarjun, a south-dipping thrust separates the Early Miocene beds from the overlying Proterozoic succession. The thrust enters Nepal from Kumaun (across the Mahakali or Kali River, south of Darchula) and runs through Baskot, north of Gwani, and Agar. Then, it crosses the Nau Gad and the Chameliya River, and continues to the southeast. There is a sharp disconformity between the grey to light grey dolomites and overlying grey-green pebbly sandstones or conglomerates. The sequence is followed upwards by red-purple shales or mudstones. At the fault zone, Mesoproterozoic grey stromatolitic dolomites and black slates rest over the Early Miocene succession of redpurple shales and grey-green sandstones. This youngest Lesser Himalayan succession varies in thickness from less than 50 m to more than 400 m. Owing to subsequent southvergent deformation, the beds are frequently overturned and steeply dip due north. These beds belong to the Suntar Formation of Shrestha et al. (1985) and are homotaxial with the Dagshai Formation of Fuchs (1981). The south belt of the inner Lesser Himalayan Tertiary succession of far-west Nepal is represented by the Chuchura Formation, made up of red-purple or brown mudstones and shales interbedded with grey-green sandstones. There are also some medium to thick (30 cm to 1 m), light grey, lenticular Nummulitic limestone beds intercalated in 20–30 m thick green-grey feeble shales with lenses of compact bivalves (Dhital, 2008). Fuchs and Frank (1970) mapped the discontinuous Tertiary beds in the inner as well as outer Lesser Himalaya of west Nepal, between the rivers Kali Gandaki and Thulo Bheri, as the Subathu and Dagshai Formations. They comprise red-purple, brown and 26


grey-green sandstones and shales with sporadic lenticular limestone beds. Assilina and small Nummulites have been reported from their Rukum Nappe in the Barikot area of inner Lesser Himalaya. While mapping the outer Lesser Himalayan rocks of the Tansen area in west Nepal, Sakai (1983) distinguished the Bhainskati Formation and Dumri Formation. Sakai (1983) assigned a Mid to Early Eocene age to the Bhainskati Formation and an Early Miocene age to the Dumri Formation. Gautam (1989) palaeomagnetically dated the Dumri Formation of the Tansen area at 40 Ma. On the other hand, Najman et al. (2005) dated the Dumri Formation at younger than 30 Ma based on detrital zircon fission track data, whereas DeCelles et al. (2001) dated them at younger than 20 Ma on the basis of Ar–Ar ages of detrital white micas. The studies of the inner Lesser Himalaya in the Syangja area of west Nepal have also revealed the distribution of Tertiary rocks as a thin discontinuous horizon occupying the top part of a backthrust constituting a triangle zone (Dhital et al., 2002). Dhital and Kizaki (1987a) worked out the lithology and stratigraphy of the outer Lesser Himalaya in the Dang, Sallyan, and Piuthan districts of west Nepal and mapped the Tertiary rocks under the Sattim and Dubring Formations. In this area, the Nummulitic limestone beds occur in two distinct lithofacies: 1) in the upper part of the Sattim Formation, interbedded with light to dark grey-green sandstones and grey-green, black, and dark grey shales containing compact lenses (coquinite) as well as intact scattered pieces of gastropods and pelecypods; and 2) in the lower part of the Dubring Formation, interbedded with grey-green sandstones and red-purple calcareous shales. The lithology of the Nummulitic limestone-bearing succession from the upper part of the Sattim Formation is very similar to the Subathu Formation, whereas that of the Dubring Formation is akin to the Dagshai Formation. The contact between the Sattim Formation and the overlying Dubring Formation is transitional. The Tertiary rocks of these areas frequently lie in the imbricate slices of a duplex (Dhital and Kizaki, 1987b). References: 1. Auden, J. B. (1934) The geology of the Krol Belt. Records of the Geological Survey of India, 67, 357–454. 2. DeCelles, P. G., Robinson, D. M., Quade, J., Ojha, T. P., Garzione, C. N., Copeland, P., and Upreti, B. N. (2001) Stratigraphy, structure, and tectonic evolution of the Himalayan fold-thrust belt in western Nepal. Tectonics, 20, 487– 509. 3. Dhital, M. R. and Kizaki, K. (1987a) Lithology and stratigraphy of the Northern Dang, Lesser Himalaya. Bulletin of the College of Science, University of the Ryukyus, 45, 183–224. 4. Dhital, M. R. and Kizaki, K. (1987b) Structural aspect of the Northern Dang, Lesser Himalaya. Bulletin of the College of Science, University of the Ryukyus, 45, 159–182. 5. Dhital, M. R. (2008) Lesser Himalayan Tertiary rocks in west Nepal and their extension in Kumaun, India. Journal of Nepal Geological Society, 37, 11–24.

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6. Dhital, M. R., Thapa, P. B., and Ando, H. (2002) Geology of the inner Lesser Himalaya between Kusma and Syangja in western Nepal. Bulletin of Department of Geology, Tribhuvan University, 9, 1–60. 7. Fuchs, G. and Frank, W. (1970) The geology of west Nepal between the rivers Kali Gandaki and Thulo Bheri. Jahrbuch der Geoloischen Bundeanstalt., Sonderband, 18, 103. 8. Fuchs, G. (1981) Geologic–tectonical map of the Himalaya, scale: 1:2 000 000. Geologische Bundesanstalt, Wien. 9. Gautam, P. (1989) Magnetic properties of some Late Paleozoic to Tertiary sedimentary rocks of Tansen area, Lesser Himalaya, Nepal. Jour. Fac. Sci., Hokkaido Univ. Ser. IV, 22, 467–487. 10. Najman, Y., Carter, A., Oliver, G., and Garzanti, E. (2005) Provenance of early foreland basin sediments, Nepal: constraints to the timing and diachroneity of early Himalayan orogenesis. Geology, 33, 309–312. 11. Sakai, H. (1983) Geology of the Tansen Group of the Lesser Himalaya in Nepal. Mem. Fac. Sci. Kyushu Univ. Ser. D. [Geol.], 25(1), 27–74. 12. Shrestha, S. B., Shrestha, J. N. and Sharma, S. R. (1985) Geological map of FarWestern Nepal. Published by the Department of Mines and Geology, Kathmandu. 13. Wadia, D. N. (1957) Geology of India. Third Edition (Revised), Macmillan & Co Ltd, New York, 536 p. (with maps).

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SEDIMENTARY RESPONSES TO FORCED REGRESSION ACROSS SUBATHU - DAGSHAI BOUNDARY IN NW HIMALAYAN FORELAND Partha Pratim Chakraborty1 and Melinda K. Bera2 1

Department of Geology, University of Delhi, Delhi 110007 Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur 721302 E-mail: [email protected]

2

Sedimentology and sequence stratigraphic analysis in parts of the Himalayan peripheral foreland basin, northwest India suggest tectonically-driven forced regression in course of transition from marine Subathu Formation to the continental Dagshai Formation. Documentation of sandstone and carbonate mass flow products with widely varying rheology all through the marine Subathu package bear tell-tale evidence in favor of operation of basinal turbidites, derived from both orogenic and ramp sides of the foreland during progressive uplift of basin margin/s. Bounded between the “Surf diastem” below and type 1 unconformity at its top, the shoreface 'White sandstone' represents a forced regressive wedge and emplaced in course of forced regression. The history of forced regression in the 'White Sandstone', however, differs from RSME (regressive surface of marine erosion, occurring below) bounded FRWs described from other classical coastal/foreland settings. Petrography of sandstones and their Sr and Nd isotopic compositions indicate a major provenance switchover from dominant mafic/ultramafic to metamorphic source from the White sandstone (∼ 31 Ma) onwards attesting the link between hinterland tectonics, provenance and forced regression. The definite signature of channel incision indicate the unconformity between the Subathu and Dagshai Formations and is interpreted as a Type 1 sequence boundary and the unconformity is inferred to be ≤3 m.y. duration, contrary to an earlier claim of >10 m.y. duration. Using the logged thickness of the Subathu/Dagshai transition zone including the White sandstone (bounded between the “Surf diastem” and unconformity), available chronology and rate of eustatic sealevel fall (0.023 mm/year at 31 Ma), a higher rate of sea level fall compared to the sedimentation rate (0.07 mm/year) is inferred during the unconformity generation and deposition of the forced regressive wedges in form of White sandstone.

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PALAEODEPOSITIONAL AND MICROFACIES ANALYSIS OF PALAEOGENE SUBATHU FORMATION, LESSER HIMALAYA IN GARHWAL AND MUSSOORIE SYNCLINE, UTTRAKHAND S. R. Mishra1, Rabishankar Karmakar2, Rajuram Sarswat3, Srirupa Gupta1 and S. C. Tripathi1 1

Geological Survey of India, Northern Region, Lucknow 2 Geological Survey of India, Eastern Region, Kolkata 3 Geological Survey of India, Western Region, Jaipur E-mail: [email protected]

Sedimentary record in the peripheral foreland basin of the Himalaya provides a unique opportunity to study the chronology of India-Eurasia collision and the way in which sedimentary sequences develop in response to progressive evolution of the basin vis-à-vis marine transgression. The Paleogene sequence of the Himalayan foreland basin is represented by the rocks of Subathu Formation, which rests along a regional unconformity over the rocks of Precambrian-Cambrian/Cretaceous age at different places in NW Himalaya. This unconformity, often marked by bauxite-laterite (palaeosol) is poorly developed. The rocks of Subathu Formation tectonically rest over the Siwalik Group of rocks along the Main Boundary Thrust (MBT) and are exposed in several discrete and discontinuous outcrops in different synclines and inliers throughout the NW Himalaya. The detailed study has been carried out in the Garhwal and Mussoorie synclines of Lesser Himalaya of Uttarakhand. Based on the sedimentological characteristic and variation in biota eight microfacies (MF) have been identified. The identified microfacies, are i) Oolitic Ironstone (MF-1), ii) Nummulites wackestone (MF-2), iii) Assilina wackestone (MF-3), iv) Nummulites packstone (MF-4), v) Assilina Nummulites packstone (MF-5), vi) Oyster bearing grainstone (MF-6), vii) Turritella/Pelecypod bearing shale (MF-7), and viii) Upper sandstone (MF-8). The microfacies have been correlated with the eustatic changes, hence a sequence model has been proposed for the depositional environment of Subathu Formation. The base of the Subathu Formation is marked by the development of a thin palaeosol horizon marked by the lateritic layer and carbonaceous shale indicating a sedimentation gap between Cretaceous-Palaeogene marine sequences in Garhwal Himalaya. The paleosol horizon is succeeded by Oolitic ironstone. It refers to the initiation of sedimentation in the Paleocene time under paralic conditions at the beginning of transgressive phase in which carbonaceous shale and oolitic ironstone (swamp material/lagoonal deposits) were deposited followed by shallow marine conditions with the deposition of grey shale, lensoidal limestone (containing fossils of foraminifers) and shell limestone depicting open marine environment and warm water condition. The microfacies analysis of Subathu Formation denotes that MF-1 to MF-4 define the stacking pattern of deposition in transgressive system tract (TST) whereas the Maximum 30


Flooding Surface is marked by Nummulite-Assilina packstone (MF-5). The MF-6 and MF-7 comprise of green shale, siltstone and greenish grey sandstone containing pelecypod and gastropods depicting shallow marine condition but during this sequence sea level is in progressive phase of shifting towards regressive phase. The sea slowly regressed thereafter at the end of MF-7, however faster rate of RSL fall, higher than the sedimentation rate, has been inferred for the erosion of the lower shoreface and RSME towards the end of MF-8. Progradation and termination of distal marine sedimentation can be triggered by lowering of base level (during Forced Regressive System Tract (FSST).

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FACIES ANALYSIS AND DEPOSITIONAL ENVIRONMENT OF THE LATE PALEOCENE-EARLY EOCENE NAREDA FORMATION, KUTCH, WESTERN INDIA V. K. Srivastava and B. P. Singh Centre of Advanced Study in Geology, Banaras Hindu University E-mail: [email protected]

The late Paleocene-early Eocene Nareda Formation represents the initial marine sedimentation in Kutch during Tertiary period. The overall, 22 m thick succession of Nareda Formation, exposed along cliff (N 23034’36.8”; E 68038’38.1”) of the tributary of the Kakdi River, is dominantly composed of argillaceous and bio-chemically precipitated carbonate rocks of marine origin. A total of eight lithounits have been identified; those are alternate green shale and brown shale facies in the lower part followed by wackestones with calcareous nodular band, sparitic packstones, organically bounded framestones (bioherm), clayey limestone, coquina packstone and ferruginous coralline limestone in ascending order in the upper part. The bedding planes are horizontal to slightly inclined (< 3°) and/or slightly wavy. The green as well as brown shale facies are splintery in nature and show horizontal interlamination with gypsum layers. Both these facies contain glauconites with circular to elliptical grain boundaries and radial fractures, thus suggesting deposition on a mid- to outer-shelf marine depositional setting (within depth range of 50-100 m). The overlying horizontally-bedded wackestone facies with nodular band and sparritic packstone both endowed with fossil shells of larger benthic foraminifera e.g. Assilina, Nummulites, Globorotalia in association to ostracods, bivalves and gastropods shells, depict their deposition in mid- to inner-shelf marine realm under normal seawater salinity. The abundance of peloids and calcispheres in these facies shows replacement of some of the ostracods, bivalves and gastropods shells by sparry calcite which might have been precipitated from oversaturated sea water under tropical climatic condition. The overlying organically bounded framestone (bioherm) is characterized by slightly undulated tabular form showing reef growth at outcrop section whereas framework of curvi-radial concentric growth of carbonate layers under thin section indicates reef formation at shallow marine depositional setting in warm tropical water under normal seawater salinity. The thickly-bedded brown colour clayey-limestone indicates deposition during shallowing of the lagoon. The overlying coquina packstone facies studded with various fossil shells, most of them are micritized, resembles its deposition under inner shelf or lagoonal environments which is overlain by an intertidal coralline limestone deposit showing complete to partial replacement of some of the coral shells by ferruginous mineral as well as secondary precipitation of the same within the pores during late diagenesis. Therefore, based on these facies association and their genetic link to characteristic depositional milieu, authors have proposed an overall shallowing-upward marine depositional system for Nareda Formation. 32


SEQUENCE STRATIGRAPHIC SIGNIFICANCE OF DISCONTINUITY SURFACES DURING PALAEOGENE: INSIGHTS FROM CORRELATION OF KACHCHH AND JAISALMER BASINS OF WESTERN INDIA Rajendra Dutt Saklani and Bhawanisingh G. Desai School of Petroleum Technology Pandit Deendayal Petroleum University Raisan Village, Gandhinagar-382007 E-mail: [email protected]

The Paleogene sediments of Western India are well exposed in the Kachchh and Jaisalmer Basins and comprises of fossiliferous limestones sequence. Temporal and spatial correlation of the Middle Eocene sediments reveals several depositional breaks that represent discontinuity surfaces (DS). These are characterized by ichnological variations and taphofacies variations across these breaks. In Kachchh Basin, stratigraphic basal sea level stand especially during early Middle Eocene is marked by development of intensive laterization horizon, which are overlain by marine transgression characterized by a succession rich in trace fossils like Psilonicnus, Rossellia, Thalassinoides etc. The overlying sediments shows retrogradational parasequences with multi-genetic event shell accumulations with a distinct discontinuity surface in between. The Maximum flooding surface is marked by a Gastrochaeonolite borring surface suggesting formation of Firmground conditions with low rate of sediments. In contrast, in the Jaisalmer Basin the sedimentation does not show any prominent discontinuity surface on account of lowering of the sea level. However, the Jaisalmer succession shows very well developed retrogradational parasequences with moderately diverse trace fossil assemblage consisting of Thlassinoides, Teichichnus etc. The end of the Middle Eocene is marked by karstified surface in both of the basin indicative of drop in sea levels, exposing the sediments for lithificaiton and karstification process. Systematic data analysis reveals: (1) During Middle Eocene times frequency and lateral extent of (DS) was cyclic and reaches a maximum development in the shallower higher-energy setting, whereas both frequency and lateral extent of DS surfaces development decreases seawards or in deeper and low energy setting, and (2) Formation of firm grounds mainly in relative low-energy settings. Thus, the end of the Middle Eocene marks a regional event common to both of the basins, indicative of usefulness and applicability of discontinuity surface in sequence stratigraphy.

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PALEOGENE EVENTS OF THE MANIPUR REGION, INDIA Y. Raghumani Singh1, Umarani Sijagurumayum1 and B.P. Singh2 1

Department of Earth Sciences, Manipur University, Imphal-795003, India 2 CAS in Geology, Banaras Hindu University, Varanasi-221 005, India

We try to highlight Paleogene events of the Manipur region on the basis of fossil evidences. The Paleogene succession of the Manipur region is represented by the Disang and Barail Groups that are mainly exposed in the Imphal valley. In the present investigation, 108 species (80 bivalves and 28 gastropods) belonging to 51 genera of bivalves and 26 genera of gastropods have been recovered from the Upper Disang Formation of Changamdabi area of Imphal valley. Based on the assemblage, three biostratigraphic zones namely Zone I-Caestocorbula (Parmicorbula) regulbiensisFlemingostrea pharoanum aviculina with age ranging from Late Paleocene – Early Eocene (Thanetian – Ypresian), Zone II -Vulsella pakistanica-Corbula (Varicorbula) daltoni with age from Middle Eocene-Late Eocene (Ypresian - Bartonian) and Zone III Callista (Callista) yawensis and Lucina yawensis with age assigned as Late Eocene (Priabonian) were identified in ascending order of stratigraphy. Two ecological events in the Upper Disang Formation are identified i.e. shallowing of the sea-aerated water corresponding to Zone I and open sea conditions with well-aerated warm water condition corresponding to zones II and III. The occurrence of dinoflagellates (Eocene), flasher bedding and lenticular bedding in the shale, siltstone and sandstone containing succession of the Upper Disang of Gelmoul quarry (Churachandpur) suggests a shallow marine (tidal-flat) depositional environment. The overlying plant fossils containing Barail sequences (Oligocene) of Kaina Hills, Imphal valley indicate coastal/terrestrial environmental condition under warm and humid tropical climate. Thus, there is a shallowing up in the depositional environment from Upper Disang Formation to Barail Group.

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PALYNOFACIES STUDY OF LAKADONG LIMESTONE (LATE PALEOCENE) OF MAWSYNRAM AREA, SHILLONG PLATEAU, MEGHALAYA: IMPLICATIONS FOR SEQUENCE STRATIGRAPHIC SUBDIVISION Bikash Gogoi1, Vandana Prasad2 and Rahul Garg2 1

2

Department of Geology, Gawahati University, Assam Birbal Sahni Institute of Palaeobotany, 53, University Road, Lucknow E-mail: [email protected]

Identification of proximal-distal trends for deciphering paleoenvironmental fluctuation is often difficult in sedimentologically uniform carbonate rocks. However, study of relative increase and decrease of marine and terrestrial organic matter content provides a useful tool for deciphering the deepening and shallowing cycles in monotonous carbonate build ups. In the present study, two late Paleocene successions of Lakadong Limestone Member (Sylhet Limestone Formation) exposed at Dohsniang peak (Kurtinsiang) and Laitmowksing sections of Khasi Hills, South Shillong Plateau, comprising Highstand systems tract of 3rd order sea level cycles, have been further subdivided into higher order sequences using palynofacies criteria as complementary tool. In a basin to landward transect, the two sections have been investigated for palynofacies and foraminiferal distribution pattern. Both the sections have been dated as late Paleocene based on the characteristic larger benthic foraminiferal assemblages belonging to the Tethyan Shallow Benthic Zones SBZ 3 and SBZ 4. The cyclic changes in the palynomaceral assemblages reflect sea level fluctuations of higher order cycle. Transgressive deposits including the Maximum Flooding Surface (MFS) are characterized by the high proportion of black oxidized palynomaceral along with dinoflagellate cyst whereas, varied types of degraded brown palynomaceral occur most frequently during Highstand and Lowstand progradational phases. The cyclicity in the behavior pattern of various types of palynofacies constituents help in deciphering shallowing and deepening cycles in the studied section. A transgressive deposit followed by progradational sequence constitutes one parasequence. Four parasequences have been identified in the Dohsniang peak (Kurtinsiang) and three in the Laitmowksing Section. The present study provides useful criteria for establishing higher order sea level cycles for sedimentologically uniform carbonate facies. Palynofacies study thus offers a logical approach in the correlation of parasequences and paleoenvironmental set up in different depositional setting of the basin-landward transect. The proposed subdivision of 3rd order systems tract of the Lakadong Limestone in to higher-order cycles may improve prediction of lateral and vertical variation of reservoir facies characteristics in petroleum exploration studies.

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SOME FIELD OBSERVATIONS ON THE GEOLOGY OF THE PALEOGENE BELT OF THE SIMLA HILLS, HIMACHAL PRADESH, INDIA K. Milankumar Sharma1, Ram Jivan Singh2, Tomoghno Ghosh3 and Pankaj Kumar2 1

Palaeontology Division-1, Geological Survey of India, Central Headquarter, Kolkata-700016 2 Geological Survey of India, Chandigarh-1600033 3 GHRM Cell, Geological Survey of India, Central Headquarter, Kolkata-700016 E-mail: [email protected]

The collision of Indian Plate and Eurasian Plate during Palaeocene around 55 Ma, produced upwarp/bulge along the leading edge of the Indian Plate forming ProtoHimalaya, closure of the Tethyan sea and successively southward an elongate Paleogene foredeep/foreland basin all along the then Proto-Himalaya. This shallow marine basin received sediments mostly from rising Proto-Himalaya to deposit shallow marine, fossiliferous shale, siltstone and impure limestone of the Subathu Formation, the lowermost lithostratigraphic unit of the Sirmur Group in the Himachal Himalaya. The Subathu Formation overlain on the various pre-Tertiary lithostratigraphic units likes Simla Group, Krol Group, Baliana Group and Shali Group/Deoban Group with a thin (10-30 cm) layer of laterite/bauxite. The overlying fluvial, sedimentary rocks of the Dagshai Formation/Lower Dharmshala of the Sirmur Group deposited after withdrawal of the Subathu Sea or marine regression due to tectonic upheaval of the Paleogene basin. The rediush-purple mudstone and greyish-brown, fine to medium grained sandstone of the Dagshai Formation show development of caliche bearing calcisol towards the basal part, above white arenite unit of the uppermost Subathu Formation. The plant fossils bearing fluvial, medium to coarse grained, massive, multistorey, greenish-grey micaseous sandstone and minor grey-orange mudstone of the Kasauli Formation have transitional contact with the underlying Dagshai Formation, the topmost lithostratigraphic unit of the Sirmur Group. The NNW-SSE trending Paleogene fold-thrust belt lies between the northerly dipping Krol Thrust/Main Boundary Thrust (MBT) in north and the Main Boundary Fault (MBF) in south. Few outliers of the Kakara Formation (i.e. equivalent to lower Suabathu Formation) and Subathu rocks in tectonic window near Solan were observed beyond north of the MBT along the southern part of the Lesser Himalaya. Besides these south verging regional thrusts, few south verging intraformational thrusts of regional extent like the Ranon Thrust around Aunj, north Barog and Ranon and the Surajpur Thrust around Chakki ka Mor and Sultanpur along with other local intra-formational thrusts/reverse faults were also observed in the area. The thrust related deformation structures like fault associated with drag folds, overriding of older rocks on younger rocks, repetition and omission of lithostratigraphic units, brittle shear zones, various fault zone rocks like fault gouge and breccia, intermingling of litho-units, shattering and steepening of beds, thrust related antithetic and synthetic secondary fractures/micro-faults and joints with or 36


without slickensides bearing slip planes were observed along the major thrust zones in the area. The Paleogene rocks show NNW-SSE trending, regional F1 folds and S1 cleavages without recrystallisation and NE-SW to N-S trending cross F2 folds with discrete joints. The rocks of the Subathu Formation were exposed mostly along the core of the regional F1 folds, a second order topography. The rocks of the Sirmur Group show well preserved primary sedimentary structures like beds, cross beds, load cast, slump structures and ripple mark. The presence of intense zones of bioturbation or ichnofacies of Psilonichnus isp., Bergaueria isp., Skolithos isp. and Thallasinoides isp. within the top part of the Subathu Formation below its litho-contact with the younger Dagshai Formation indicates landward shift of the facies probably resulted from the regression of Subathu Sea. Locally, the top white arenite unit of the Subathu Formation as exposed near Subathu, Dharampur, Kumarhatti and Kumarhatti-Johorji shows development of local calcrete and ferruginous nodules probably due to onset of fluvial erosion and weathering which signify a possible time gap between marine Subathu to fluvial Dagshai formations.

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GEOCHEMICAL PROVENANCE OF PALEOGENE SEDIMENTS IN ANDAMAN FOREARC: IMPLICATIONS FOR PALEOGENE DRAINAGE IN SOUTH ASIA Jyotiranjan S. Ray and Neeraj Awasthi Physical Research Laboratory, Navrangpura, Ahmedabad-380009, India E-mail: [email protected]

Andaman and Nicobar Islands are part of an accretionary wedge formed on the outer-arc ridge of the Andaman subduction zone. The ridge is an imbricate stack of fault slices consisting of Cretaceous seafloor ophiolites and Paleocene to Holocene terrigenous and pelagic sediments. Deposited along the convergent margin of the Indian and Burma plates, the sedimentary rocks of these islands are believed to have recorded the evolutionary history of the Indo-Myanmar-eastern Himalayan region. Geochemical and Sr-Nd isotopic ratio studies were carried out on samples collected from siliciclastic formations to establish the sources of the terrigenous sediments and their transport pathways. New age constraints (72.0 to 0.73 Ma) were placed based on Sr-isotope stratigraphy of carbonate formations and 40Ar/39Ar dating of a tuff horizon. Nd(0) of the Paleocene-Eocene trench-slope sediments (Mithakhari Group) vary from -8.1 to +4.2 (87Sr/86Sr = 0.70497 to 0.71554) and that of the overlying Oligocene forearc sediments (Andaman Flysch Group) range from -12.7 to -9.4 (87Sr/86Sr =0.71548 to 0.73049). We determine that the Mithakhari Group sediments were primarily derived from the ophiolitic basement and/or magmatic arc (>80%) with minor contributions from the continental sources. The latter sources started dominating (20-40%) during the deposition of the Andaman Flysch Group. This trend clearly coincides with the timing of attainment of critical height of the Himalayas and establishment of the Indian monsoon system. Thus, it appears that enhanced weathering and erosion of the Himalayan rocks generated the continental sediments that ultimately got deposited in the Indo-Burman-Andaman fore-arc basin, which in turn suggests the existence of active drainage system in the eastern Himalayas, possibly the proto-Brahmaputra/Irrawaddy, which provided the transport pathways.

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SIGNATURES OF PALEOCENE–EOCENE THERMAL MAXIMUM IN SUBATHU SUCCESSION, NW SUB-HIMALAYA, INDIA Smita Gupta and Kishor Kumar Wadia Institute of Himalayan Geology 33 General Mahadeo Singh Road, Dehradun 248001, India E-mail: [email protected]; [email protected]

The Paleocene–Eocene Thermal Maximum (PETM) was a shortglobal warming event which occurred at ~55Ma and lasted for ~170-200 Kyrs. It was in response to injection of large amount of depleted 13C carbon into the oceanic-atmospheric systems reflected by the worldwide negative carbon isotope excursion (CIE). It resulted in widespread deep-ocean acidification, carbonate dissolution,change in ocean geochemistry and major biotic turnovers as reflected in fossil records of many organisms throughout the world.Some of the markers for identifying the PETM in sedimentary archives are bloom of dinoflagellate Apectodinium, turnover of larger foraminifera, diversification of planktic foraminifera, fluctuations in nannofossil assemblages, negative carbon isotope excursion, carbonate dissolution, silicate weathering, increase in phyllosilicate abundance and enhanced fluvial input, etc. The oldest unit of the sub-Himalayan Paleogene succession, i.e., the Subathu Formation was deposited during the late Paleocene-middle Eocene interval in a shallow marine setting with occasional influence to open sea and hence it ought to have preserved valuable information on the abrupt global warming event. With this premise in mind we investigated a few sections of the basal part of the Subathu Formation of the stratotype area in Himachal Pradesh, and herein we present the preliminary results. In the present study we used larger foraminifera, bloom of index dinoflagellates and carbon isotope stratigraphy to identify the PETM. Bulk mineralogical and geochemical analyses were undertaken to see the changes in the basin chemistry. In the studied section, carbonate dissolution of larger foraminifera, Apectodinium dinoflagellate cyst acme (including A. parvum, A. homomorphum, A. quinquilatum) and the CIE of 3.4‰ have been noted. The Apectodinium acme coincides with the base of the CIE, where changes in bulk mineralogical and major oxide geochemistry are also observed. Increase in aluminosilicates and phyllosillicates took place at the expense of carbonates close to the PETM marking increase in erosion rates and run off in the basin. Clearly, signatures of the PETM are reasonably well reflected in marine biota as well as sediments of the basal part of the Late Paleocene–Middle Eocene Subathu Formation.

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QUANTIFICATION OF WARMING EVENTS DURING THE PALEOGENE IN INDIA: EVIDENCE FROM FOSSIL CLIMATES Gaurav Srivastava Birbal Sahni Institute of Palaeobotany 53, University Road Lucknow- 226 007 E-mail: [email protected]

Climate during the Cenozoic shows an overall cooling trend despite several warming events. In the Cenozoic, the Paleogene experienced two globally extreme warm phases often known as PETM (Paleocene-Eocene Thermal Maxima) and late Oligocene warming. Due to the warming several biota either from land or sea migrated towards the pole. Quantification of such warming events, particularly in the lower latitudes is still challenging using the isotopic proxies which are prone to diagenetic effects. The isotopic reconstruction of deep marine temperature may not be complimentary to the land air temperature as ocean response time is much longer than the atmosphere for such small fluctuations due to the differences in specific heat capacities of water and air. Under such conditions, land plant proxies are fairly ideal for the reconstruction of palaeoclimate. For the reconstruction of aforesaid warming events, two fossil sites were used such as Gurha lignite mine in Rajasthan, western India (27.8º N, 72.8 º E) and Tirap mine Makum Coalfield in Upper Assam. The former is considered as early Eocene in age and was located at ~9º N palaeolatitude, while the latter is considered as late Oligocene in age and was located in between 10–15º N palaeolatitude. For the quantification of palaeoclimate CLAMP (Climate Leaf Analysis Multivariate Program) which only relies on the leaf physiognomy and requires a minimum 20 different leaf morphotypes, has been used. The reconstructed climate during the early Eocene indicates a MAT (mean annual temperature) of ~25 ±2.8 ºC, WMMT (warm month mean temperature) of ~28 ±3.4 ºC, CMMT (cold month mean temperature) of ~18 ±4 ºC, MAP (mean annual precipitation) of ~180 ±91.6 cm and the ratio of 3WET and 3DRY months is 11.8:1 which is nearly similar to the modern day ratio of about 12.8:1 indicating a similar and strong monsoon. Similarly, the late Oligocene indicates a MAT of ~26.1 ±2.7 ºC, WMMT of ~ 29 ±3.3 ºC, CMMT of 20.1 ±4.3 ºC, MAP of ~246 ±30.7 cm and the ratio of 3WET and 3DRY months is 20:1 indicating a strong monsoon during the deposition of the sediments. The overall reconstructed climate from both the sites indicates that the early Eocene experienced slightly cooler temperature and lesser rainfall than late Oligocene; as supported by leaf architecture. The reconstruction indicates the existence of South Asia monsoon during Paleogene.

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EFFECT OF GLOBAL WARMING ON DIVERSITY PATTERN IN NYPA MANGROVES ACROSS PALEOCENE-EOCENE TRANSITION IN THE PALAEO-EQUATORIAL REGION OF THE INDIAN SUB-CONTINENT Jyoti Srivastava and Vandana Prasad Birbal Sahni Institute of Palaeobotany, Lucknow E-mail: [email protected]

The Paleocene-Eocene transition has been considered a period of excessive global warming that characterizes the highest temperature of the Cenozoic. In order to trace the response of mangrove vegetation to this early Paleogene warming, species diversity of back mangrove palm genus Nypa has been studied across the Paleocene/Eocene boundary interval from the palaeo-equatorial zone using palynological data. Two shallow marine stratigraphic sections Ranikor Barsora and Jathang from the East Khasi Hills, South Shillong plateau, Meghalaya were taken up for the study of diversity changes in Spinizonocolpites (Nypa pollen) during pre and post Palaeocene/Eocene boundary time interval. Statistical analyses on significant pollen counts from 93 samples were carried out to assess the diversity pattern of the palaeo-mangrove flora and palaeoecological trends before and after the global warming event of the geological past. The palynological data is complemented by the estimation of real biodiversity through Shannon-Wiener index, Simpson diversity index and rarefied richness curves. Detrended correspondence analysis also showed a higher equivalent diversity during the P/E boundary with 12 equally common species as compared to 7 equally common species of the late Ypresian. Based on this study it is inferred that high precipitation, low seasonality, good upstream runoff, excessive humidity and prevalence of brackish water environments created oligohaline conditions in the coastal areas during Paleocene/Eocene boundary interval in paleo-equatorial region. This favoured the diversification of mangrove palm Nypa, providing opportunities for several new species in a wide range of low saline tidal zones to flourish. Post warming during late Ypresian concurrent setting of a high seasonality climatic regime led to a decrease in precipitation, humidity and low upstream runoff. This resulted in the restriction of low saline tidal zones in coastal areas, thus causing a decline in the diversity of Nypa mangrove. Hence, mangrove dynamics, as represented by the variations in species diversity and origination rates of the back mangrove palm genus Nypa described under Spinizonocolpites during the PalaeoceneEocene transition constitute an important step in understanding the effect of global warming on mangrove vegetation in palaeo-equatorial region.

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HOW OLD IS THE INDIAN MONSOON SYSTEM? GEOCHEMICAL EVIDENCES FROM THE ANDAMAN FORE-ARC BASIN Neeraj Awasthi and Jyotiranjan S. Ray Geosciences Division, Physical Research Laboratory Navrangpura, Ahmedabad, 380009, India E-mail: [email protected]

Strong monsoonal systems in Asia are believed to have originated between 25 and 22 million years (My) ago and are considered to be mainly driven by Tibetan–Himalayan uplift (Guo et al., 2002; Qianget al., 2011).However, the knowledge of Tibetan– Himalayan uplift and their response to climate change are unknown because of the paucity of well-dated and well-studied sedimentary records from much part of the Paleogene (55–25 My ago). Here we have investigated geochemical and isotopic data from the study of the Oligocene sedimentary rocks of the Andaman forearc Basin (exposed on the Andaman Islands). Our results show major inputs of Himalayan detritus to the Andaman forearc basin since the late Eocene similar to results obtained from the study of the Barail Group sediments in the Bengal Basin (Bangladesh) further north of our studied site. In the data a marked increase in weathering indices (e.g. CIA, PIA etc.) and sedimentation rates is clearly visible. We envisage that huge volume of sediments supplied to the Andaman forearc basin and also to the Bengal Basin during late EoceneOligocene were results of large scale weathering in the nascent Himalayas (Najmanet al., 2008; Pal et al., 2003). This enhanced weathering and erosion of the exhuming continental crust and resultant exponential increase in the sediment input to the adjacent basins is not possible in absence of strong monsoon systems. Probably until late Eocene, Himalayas had attained the critical height that provided sufficient topographic barrier to the moisture laden winds from the south and resulted in the development of the first monsoon system. A recent study from Myanmar support existence of monsoon-like patterns in rainfall during late Eocene (Licht et al., 2014). However, still more data is required from the Indian subcontinent to confirm existence of the Indian monsoon during the Paleogene. References: 1. Guo, Z. et al.(2002) Onset of Asian desertification by 22 Myr ago inferred from loess deposits in China. Nature, 416, 159–163 2. Qiang, X. et al.(2011) Neweolian red clay sequence on the western Chinese Loess Plateau linked to onset of Asian desertification about 25 Ma ago. Sci. China Earth Sci., 54, 136–144. 3. Najman, Y. et al.(2008) The Paleogene record of Himalayan erosion: Bengal Basin, Bangladesh. Earth and Planetary Science Letters, 273, 1-14.

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4. Pal, T. et al.(2003) Geodynamic evolution of the outer-arc-forearc belt in the Andaman Islands, the central part of the Burma-Java subduction complex. Geological Magazine, 140, 289-307. 5. Licht, A. et al.(2014) Asian monsoons in a late Eocene greenhouse world. Nature, 513, 501-506.

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TAPHONOMY AND PALEOECOLOGY OF PALEOCENE-EOCENE CALCAREOUS ALGAE FROM MEGHALAYA, N-E INDIA Suman Sarkar Birbal Sahni Institute of Palaeobotany, 53 University Road, Lucknow – 226 007 E-mail: [email protected]

Calcareous algae are conspicuous and important components of the Paleogene sedimentary deposits in the Indian subcontinent. The present paleontological investigation has been carried out from the Paleocene-Eocene carbonate units of the Sylhet Limestone Group (Lakadong Limestone, Umlatdoh Limestone and Prang Formation) outcropping on the Jowai-Badarpur Road in Jaintia Hills, Meghalaya (N-E India). Calcareous algae are represented by common to abundant assemblages in different time slices of the Paleogene carbonates. The non-geniculate coralline algae show a wide range of growth-forms viz., encrusting, unconsolidated, warty, lumpy, fruticose, layered and arborescent. Physical fragmentation, abrasion, bioerosion and disarticulation represent the main processes responsible for post-mortem damage/taphonomy. A considerable amount of unidentifiable algal debris is observed in all the studied sections that can be possibly the result of strong abrasion caused by transport and sediment agitation, ultimately leading to removal of diagnostic characteristics essential for fossil algae identification. Contrary to these negative taphonomic forces, encrustation by other organisms resulted in an increase in the preservation potential of several algal thalli. Dis-articulation is uniformly observed in all the geniculate coralline algal specimens that can be attributed to the loss of soft, uncalcified genicula leaving behind the commonly observed calcified intergenicula. The arborescent growth-form can be visualized for the fossil geniculates based on comparison with their living counterparts. Four moderate to high-diversity algal assemblages can be recognized, each of them strongly dominated either by mastophoroid or melobesioid coralline algae in association with lithophylloids, sporolithaceans and calcareous green algae. Calcareous green algae including Halimeda, Ovulites and rare dasyclads are completely absent in the Lakadong Limestone but contribute significantly to the Umlatdoh and Prang carbonate sediments. The general ecological preferences of the main skeletal contributors in the fossil assemblages form the basis for relating the algal associations to broad shelf habitats. The reported calcareous algae in association with other common biogenic facies components like the benthic foraminifera indicate restricted lagoonal to proximal outer shelf environmental zonations. On basis of the algal assemblages, overall shallow bathymetric levels and mesotrophic nutrient regime is interpreted. Both coralline algal taxa in particular and the algal assemblages as a whole represent distinct relationships between water depth and substrate conditions. This makes them potentially valuable indicators for paleoecological reconstructions. Occurrence of mastophoroid Lithoporella and sporolithacean Sporolithon in good proportions throughout the evolution of the Sylhet Limestone Group point out a tropical paleoenvironment.

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SEDIMENTOLOGICAL INVESTIGATION OF THE EARLY PALEOGENE SUCCESSION OF JAISALMER BASIN, RAJASTHAN WESTERN INDIA A. Patra and B. P. Singh Centre of Advanced Study in Geology, Banaras Hindu University, Varanasi-221005 Email: [email protected]

The Jaisalmer Basin is the eastern extension of the shelf part of the Indus Basin and represents a more or less central part of the "West Rajasthan Shelf" tectonic province that is located to the west of the Aravalli ranges. The early Paleogene succession of the Jaisalmer Basin has hydrocarbon potential. This succession is dominantly represented by calcareous and argillaceous rocks with a subordinate proportion of arenite in the basal part.Provenance of the late Paleocene sandstone of the Jaisalmer Basin has been determined by petrographic and study of heavy minerals supported by paleocurrent study.Q-F-L and Qm-F-Lt diagrams suggest for a provenance at the margin of the craton interior and transitional continent.All these suggest that the provenance was dominated by low to medium grade metamorphic and volcanic rocks of the AravalliSupergroup, Jurassic succession and the Deccan basalts which were denuded during late Paleocene. The facies associations suggest a complete 2nd order cycle of transgression-regression of the sea from shoreface to tidal flat in the Jaisalmerpericratonic basin. Geochemistry of the Eocene limestones shows that Ca is dominant among the major elements and Ba among the trace elements. These limestones possess modern sea-water like shale-normalized REE+Y pattern with depletion of LREE and enrichment of HREE. The terrigenous input in these limestones is confirmed by the positive correlation of ∑REE with Al2O3 and negative correlation with CaO. Uranium concentration (0.4-3.7) and authigenic uranium (Total U-Th/3, average value = 0.74) indicate oxic depositional condition. The REEs of the limestones are corelatable with the shallow sea water REEs. The mixing of continental material in sea water looks possible in a shallow marine/coastal depositional environment.

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PALYNOLOGICAL STUDIES OF MATANOMADH FORMATION OF PALAEOCENE AGE FROM KACHCHH DISTRICT, GUJARAT Arvind Kumar Mathur Geological Survey of India, Western region, Jaipur E-mail: [email protected]

The palynomorphs of Matanomadh Formation are of diverse ecological group like fresh water, mangrove, back mangrove, sand dunes and beach elements. They indicate tropical environment with high annual precipitation. The fresh water flora includes Schizaeisporites, Polygalacidites, Ctenolophonidites, Restistenocolpites, Retipilonopites, Miliapolis, Margocolporites and Araliaceoipollenites. The mangrove elements are Zonocostites, spinizonocolpites, Miliapollis, Rhoipites, Araliaceoipollenites, proxapertites and Rhizophora. The sand dunes and beach elements recorded are Trilatiporites, Palmaepollinites, Longapertites, Arecipites, Dicolpopollis, Dracaenoipollis and Couperpollis. The abundance of pollen grains with natural affinity to palmae indicates near shore environment of deposition. The palynoflora of supra trappean (Matanomadh Formation) is important to find out changes in vegetation that occurred at the dawn of tertiary when dinosaurs disappeared from the earth.

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DRIFTING INDIA: A PALAEOGENE GARDEN OF EDEN? Ashok Sahni 98, Mahatma Gandhi Marg, Lucknow-226001 E-mail: [email protected]

The Biblical Garden of Eden is regarded as the birthplace of all life and fossil records of pre-Cenozoic organisms testify to many such Gardens. However, modern forms of life both plants and animals had their origination in the Early Palaeogene and it now appears that the drifting Indian Plate may hold the key in unraveling the evolutionary history of present day biota, diversity and distribution. The Cretaceous mass extinctions not only brought a change in the lifestyles of organisms but also gave rise to diversity of animals and plants not seen before on the planet. In the early Palaeogene, India was drifting as an island subcontinent, split temporarily in two parts by the Trans Deccan Straits a short-lived seaway that extended across the present Narbada Son Lineament and the Godavari Rift system. The Indian Paleocene is crucial in understanding the evolution of terrestrial plants and animals but remains poorly characterized in this respect. The advent of the Eocene gives exciting glimpses of a new world order. In the last decade or so, lignite mines in Rajasthan and Gujarat have provided a fossil record which has essentially perspectives on the evolution of tropical angiosperm forests and related vertebrates that inhabited them. One way of recognizing the initial radiation of Cenozoic mammals and their biogeographical origins is to look at three important mammalian Orders, Artiodactyla, Primates and Perissodactyla (APP for short) and their first appearance in the global fossil record at around 55 ma. The Lower Eocene of India has thrown considerable light on this radiation on the basis of three taxa: Diacodexis, (the earliest known artiodactyl), the eosimiid Anthrasimias and Cambaytherium (a sister group closest to the perissodactyla). The origin of the Cetacea also happened at this time. Apart from mammals there are several other groups with an earliest fossil record: the first angiosperm tropical rain forests with dipterocarps, social insects such as ants, wasps and termites, and fish in the oceans, the gobies. At present, it does appear that the drifting Indian Plate provided one of the ideal environments for the great Cenozoic mammalian radiation to happen, aided perhaps by greenhouse events and an isolated sub-continental island conditions as the landmass traversed several degrees of latitude to get to its present position in South Asia.

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DINOFLAGELLATE CYST BIOCHORONOLOGY OF THE LIGNITE ASSOCIATED SUCCESSION (KHARSALIA FORMATION), BHAVNAGAR, GUJARAT, INDIA Rahul Garg1, Sunil Bajpai1, Vivesh Vir Kapur1 and A. S. Maurya2 1

Birbal Sahni Institute of Palaeobotany, 53 University Road, Lucknow-226 007 2 Department of Earth Sciences, Indian Institute of Technology, Roorkee E-mail: [email protected]

Early Palaeogene lignite and associated sedimentary successions straddling episodes of extreme global warming are widespread in the western part of the Indian subcontinent including Gujarat and Rajasthan. This study presents findings of the first detailed high resolution investigation of dinoflagellate cyst assemblages recovered from the lignite succession (Kharsalia Formation) exposed in the lignite mine at Bhavnagar, Gujarat. The dinocyst data allows a fairly precise biochronological assessment of the studied succession. Dinoflagellate cysts were recovered from the thick shale succession immediately overlying the top lignite seam exposed in the mine section. Overall, the assemblages comprises 17 genera and 30 species and generally exhibit a low diversity but frequent occurrence of dinoflagellate cysts at most of the levels. The assemblages are dominated by Homotryblium and Cordosphaeridium, followed by Operculodinium, Fibrocysta and Muratodinium. In the lowermost part of the lithounit (Fossiliferous Shale) overlying the top seam, dinoflagellate cysts are frequent to common and include Homotryblium tenuispinosum, Cordosphaeridium fibrospinosum, C. exilimurum and Muratodinium fimbriatum, followed by the appearance of Glaphyrocysta exuberans, which marks the base of the Ypresian. This suggests that the Thanetian-Ypresian boundary possibly lies within the lower 2m of the Fossiliferous Shale unit. However, precise demarcation is not possible at present due to the non-recovery of zonal marker taxa. Dinoflagellate cysts decline in diversity and abundance in the overlying one m interval but show increased frequencies again up to the lower three m of the overlying lithounit (Grey Shale). At this level, the dinoflagellate cyst assemblages show an abundance of Homotryblium tenuispinosum with the appearance of Hystrichokolpoma cinctum and Lingulodinium macherophorum, both of which are known to have their FAD in the early Ypresian. The middle part of the Grey Shale unit (~5m thick) again shows a drop in the frequency of dinoflagellate cysts with rare to sporadic occurrence of only a few species. In the uppermost part of the Grey Shale unit, dinoflagellate cysts become more frequent in an otherwise low diversity assemblage, and are mainly represented by Homotryblium tenuispinosum, Homotryblium abbreviatum along with Muratodinium fimbriatum. The dinoflagellate cyst data indicates an age of latest Thanetian-Ypresian, possibly extending upwards into Lutetian but not younger than middle Lutetian for the studied interval. Further, it may be inferred that the succession was laid down in a fluctuating coastal swamp to marginal marine environment. 48


PALYNOLOGICAL EVIDENCE FOR AGE AND PALAEOENVIRONMENT OF PANANDHRO LIGNITE MINE SUCCESSION, WESTERN KUTCH, INDIA Rahul Garg, M. R. Rao, Sunil Bajpai and Poonam Verma Birbal Sahni Institute of Palaeobotany, 53 University Road, Lucknow-226 007 E-mail: [email protected]

The lignite bearing early Palaeogene sedimentary successions in the western part of India (Kutch, Cambay, Barmer, Bikaner areas) provide a unique opportunity to study floral diversity during episodes of extreme global warming. We present the results of the first detailed, high resolution study on dinoflagellate cyst and spore-pollen assemblages recovered from upper part of the lignite succession in the Panandhro Lignite Mine, western Kutch. The palynological data allows a precise age determination and the reconstruction of vegetational history of the region. The Panandhro palynological assemblage is diverse and rich, containing dinoflagellate cysts (16 genera and 28 species), algal and fungal spores (7 genera and 7 species), pteridophytic spores (13 genera and 19 species) and angiosperm pollen (44 genera and 60 species). The lower part of the lignitic succession (samples PLM 1-15) revealed the presence of spore-pollen only: Dandotiapsora dilata, D. telonata, Matanomadhiasulcites maximus, Proxapertites operculatus, Neocouperipollis spp. Kielmeyerpollenites spp., Tricolpites reticulatus, Lakiapollis ovatus, Tricolporopollis spp., Tripilaorites spp., Margocolporites spp., Sastriipollenites trilobatus, Striacolporites spp., Meliapollis spp., Polybrevicolporites spp., Retistephancolpites spp., and Ctenolophonidites costatus. The assemblage suggests a Late Palaeocene age for the lower part of the succession. The overlying middle part of succession (samples PLM 16-30) is represented by lignite and shale intercalations followed by thinly laminated grey and carbonaceous shales. This interval yielded a rare dinoflagellate cyst assemblage that includes Apectodinium homomorphum, in addition to a rich spore-pollen assemblage which comprises the following additional taxa, besides those recorded from the lower part of the succession, Schizeoisporites palanaensis, Retipollenites confusus, Dipterocarpuspollenites retipilatus, Albertipollenites crassireticulatus, Tribrevicolporites eocenicus, Triangulorites bellus, Dermatobrevicolporites dermatus, Retritrescolpitess spp. and Lanagiopollis spp. This dinocyst and spore-pollen assemblage indicates a latest Thanetian to early Ypresian age for the middle part of the succession. In the upper part (samples PLM 31-40), the dinocyst assemblage becomes more frequent and includes Homotryblium tasmaniense, H. tenuspinosum, H. floripes, H. abbreviatum, Glaphyrocysta exuberans and Muratodinium fimbriatum. This assemblage indicates an age not younger than middle Lutetian for the upper part of the succession

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Significantly, the appearance of Apectodinium homomorphum (sample PLM 16) possibly indicates the presence of the Thanetian-Ypresian boundary whereas the appearance of Homotryblium floripes (sample PLM 31) may point to the YpresianLutetian boundary in the studied interval. The carbon isotope studies may help corroborate the present findings regarding the precise placement of these boundaries. Finally, it is inferred that the lower part of the succession was deposited in a coastalswampy environment, the middle part in a marine coastal set up and the upper part under shallow marine inner shelf conditions.

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EOCENE-OLIGOCENE PLANKTIC FORAMINIFERAL BIOSTRATIGRAPHY IN ARABIAN SEA AND WESTERN TROPICAL INDIAN OCEAN Prabha Kalia* and L. R. Sahu Department of Geology, University of Delhi, Delhi- 110007, India E-mail: prabha.kalia @gmail.com; [email protected]

Middle Eocene-Early Oligocene planktic foraminifers have been studied at the DSDP Site 219, Arabian Sea and the Site 237, western tropical Indian Ocean in the light of currently revised taxonomy and the stratigraphic ranges (Pearson et al., 2005). MiddleLate Eocene Zones (E13 to E16) and Early Oligocene Zones (O1 and O2) are described in the core samples from 18-6 to15-1. As recorded in the GSSP, Massignano section, Italy, Eocene/Oligocene (Zone E16/O1) boundary at the Site 219 is placed above the Highest Occurrence (HO) of Turborotalia cerroezuelensis, T. cocoaensis, T. pomeroli, and T. cunialensis in the core 15-6. In the previous works (Keller et al.,1992 and Molina et al.,1993) the P17/P18 (=E16/O1) boundary was considered to be marked by the dissolution event in the core 16-2 above which the hantkeninids were absent and some typically Oligocene forms were recorded (e.g. Cassigerinella chipolensis and `G” tapuriensis). The present study records Hankenina alabamensis and Cribrohantkenina inflata higher up in the core 16.1 above the dissolution level, but these fragile index species were not found up to the core 15-6 in which the HO of a number of species of turboroatalid and subbotinid species (S. linaperta, S. yaguaensis) is recorded in the present study. The upper boundary of the Latest Eocene Zone E16 is difficult to mark as the HO of hantkeninids cannot be ascertained due to their preservational problems and the HO of turborotalid species occurs within the Zone E16. The LO of Tenuetellagemma is recorded in the Zone E16 (core 16-6) and, this species continues into the Oligocene in low latitudes. The upper boundary of the Zone O1 is marked by the HO of Psudohastigerina naguewichensis. Catapsydrax dissimilis appears in the Zone E14 (upper) in late Eocene to continue into the Oligocene Zone O2. At the Site 237 O beckmanii Zone E12 (=P13) is present followed by E14, its upper boundary is marked by the HO of Globigerinetheka semiinvoluta. The present study has shown that previously identified (Heimen et al., 1974) hiatus incorporating late Middle Eocene to late Oligocene (i.e. P15- P18 Zones ) is absent and the Zones E12-O2 are present at the Site 237, with the exception of Zone E16 /O1 boundary interval that could not physically be traced due to the non-recovery of Core section 22-05 and 22- 06; but the sediment accumulation rate of 1.4 m/my (Heimen and Vincent, 1974) suggests the presence of Zones E16 (upper) and O1(lower) within the unrecovered portion of the core section. Zone E16 is marked in the Core 23- 01 (007-008cm) but the level of extinction of Turborotalia spp. could not be marked at this Site. The extinction of Pseudohastigerina naguewichiensis marks the upper boundary of Zone O1 but its lower

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boundary cannot be placed due to non-recovery of core samples and the top of the Zone O2 lies in the core 22-3 marked by the HO of Globoturborotalia ouachitaensis. At the Sites 219 and 237, no significant change in the planktonic foraminifera species is found at the E/O boundary. The faunal turnover began at the top of E14 marked by the HO of Globigerinatheka semiinvoluta by the successive disappearance of surface dwellers and increasing number of intermediate dwellers. The successive appearance of more cold tolerant elements (e.g. T. gemma) through the Eocene resulted from migration of cooler water taxa into lower latitudes that shows a correlation between the onset of global cooling and Antartic glaciation. Some of the cancellate non-spinose species now referred to Dentoglobigerina were earlier regarded to belong to the genus Globoquadrinae, G. tripartita (Pearson, 1993) that ranges from Middle Eocene( E13) to Oligocene. In the Arabian Sea and western tropical Indian Ocean sites `tapurensis’ and `selli’ occur in late Eocene and continue into the Oligocene core samples. The down the core contamination is ruled out as no other Oligocene form is present in the Late Eocene Core samples. These forms are best regarded as the species of Dentoglobigerina that appeared in the cold late Eocene to continue in the colder early Oligocene and continued up to Pliocene. The species G. tapurensis like selli/tripartita occur in the late Eocene and Oligocene samples at the Sites 219 and 237 and deserve their placement in the cancellate, non-spinose Globoquadrina like wall with the genus Dentoglobigerina rather than Globoquadrina. * present address: 111, Shakti Apartments, Ashok Vihar Phase 3, Delhi 110052, India

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FOSSILS FROM KASAULI AND NYOMA: PALEOLATITUDINAL SIGNIFICANCE AND THEIR ROLE IN UNDERSTANDING THE TIMINGS OF INDO–CHINA COLLISION Ritesh Arya 168, Arath bazaar, Kasauli, Himachal Pradesh India E-mail: [email protected]

Interesting fossils found in Kasauli area during late 1990’s belonging to Garcinia, Gluta, Syzygium, Clinogene, Combretum and palms from Kasauli Formation had shown beyond doubt the similarity with taxa from coastal regions of Indo-Malayan including Borneo and Sumatra and Andaman Nicobar Islands which indicate well hot humid equatorial climatic conditions of deposition with major representation of evergreen elements typical of near equatorial conditions and near shore coastal marine influence on otherwise terrestrial environment prevailed during those times. Fossils of mega plants all along the Indo-Malayan Indonesian Islands established land connections for their migration during those times. The above contention on environmental regime, shallow maireine/near coastal/marine transgression at the time of deposition is further supported by fossil and sedimentological findings in Kasauli, Dharamsala, Udhampur, Jammu, Kalakot, Kargil, Alchi, Stok , Kangri range and Nyoma in the northwestern Indian Himalayas and further in Chitarwata Formation, westcentral Pakistan; and the equivalent formation in Darjeeling, West Bengal, northeastern India and Bhutan sector. All these localities when marked on the map show an interesting structural pattern revealing a lot about the history of their genesis in geological past. Interestingly on ground all the fossil plant assemblage localities show great similarity in lithologies, fossils and type of preservations with each other. The most important being the taphonomic relationship between the fossil wood and the sandstone facies which is quiet homogenous with other homotaxial localities or basins described above and show unmatched similarity in the environments of the deposition specially in the basins of Kasauli-Dagsahi, Dharamsala, Murree and Indus in Ladakh. Based on the fossil findings of Mitrgyana from the Kasauli sediments, the elevation was also found to be less then 1300m in contrast to the present height of about 2000m.This suggest that the Himalayas attained sufficient height to block the rain laden winds and thus the concept of monsoons was born. Presence of diverse assemblage of fossil flowers shows that seasonal changes had initiated during those times. Recent findings of Turetella,Venericardia, Glyptoactys, Venericardia, Cordiopsis and hundreds of yet to be identified fossil specimen collected from Nyoma in Ladakh along with oysters show close resemblance from the fossils findings from Subathu Formation which confirms beyond doubt that Subathu basin extended up to Nyoma and enjoyed equatorial position during Lower Eocene times. Since fossils from Kasauli show similar affinities with taxa of Indo-Malayan region, which can very well be interpreted

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that Kasauli Formation and its equivalent also enjoyed near coastal equatorial to subequatorial climatic conditions and latitudes may be around 5-100 north of equator at the time of deposition in contrast to 320 north, the current loaction. This implies that the major tectonic forces which gave rise to the Himalaya, were not very active during those times. Northward drifting of the uplifted Tethyan basin (during Dagsahi times) along with the Indian subcontinent took place much later then18.2 million years (based on the findings of Stephenochara ungri). If this theory is to be believed than the rate of northward drifting can be calculated and actual timing of collision and upliftment of Himalayas can be estimated.

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NEW DATA ON BASAL EOCENE LAND MAMMAL FAUNA FROM WESTERN INDIA: FOCUS ON PERISSODACTYLS Vivesh V. Kapur and Sunil Bajpai* Birbal Sahni Institute of Palaeobotany, Lucknow *E-mail: [email protected]

During the past more than a decade, concerted efforts by palaeontologists in India have led to the discovery of a remarkable early Eocene mammal fauna from the Cambay Shale (~54-55 Ma) exposed in the open pit lignite mines located around Vastan, Surat District, Gujarat, India. The assemblage comprises diverse groups including perissodactyls, artiodactyls, primates, creodonts, condylarths insectivores, apatotherians, proteutherians, rodents, bats and possible marsupials. Cambaytheriidae was named and identified as a new family of early perissodactyls with the type genus Cambaytherium (Bajpai et al., 2005) which, together with Kalitherium, another cambaythere from Vastan (Bajpai et al., 2006) dominate the Vastan large mammal fauna. Recent studies have reaffirmed, based on a detailed phylogenetic analysis, that cambaytheres are stem perissodactyls and that perissodactyls may have originated in the Indian subcontinent (Cooper et al., 2014; Clementz et al., 2010; Rose et al., 2014). Significantly, Cambaytherium has been shown to be phylogenetically close to the long known late Paleocene Chinese genus Radinskya and to the middle Eocene European genus Hallensia which was originally described as a ‘condylarth’. Furthermore, the anthracobunids, a family of large ungulate mammals from the early-middle Eocene of India and Pakistan, which was long considered to a part of the ancestral stock for elephants (proboscideans) and sea cows (sirenians) has also now been shown to be stem perissodactyls closely related to cambaytheres. Recent data suggests that Cambaytherium, Radinskya, Hallensia, and the anthracobunids may be part of a monophyletic clade.

Tapiromorphs represent the second perissodactyl group in the Vastan mammal fauna and are presently represented by an unnamed taxon known by a maxillary fragment with well-preserved molars and deciduous premolars. Preliminary phylogenetic analysis suggests that the affinities of the Vastan tapiromorph lie with some of the Asian taxa known from the early Eocene Bumbanian interval. The temporal, paleogeographic and phylogenetic context of the Vastan tapiromorph points to its potential importance in evaluating the biogeographic origins of tapiromorphs, especially in the context of India-Asia collision and the degree of connectivity/isolation of the Indian Subcontinent around the Paleocene-Eocene boundary (~55.5 Ma).

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References: 1. Bajpai, S., Kapur, V.V., Das, D.P., Tiwari, B.N., Saravanan, N. and Sharma, R. (2005a) Early Eocene land mammals from Vastan lignite mine, District Surat (Gujarat), western India. Journal of the Palaentological Society of India, vol. 50, p. 101–113. 2. Bajpai, S., Kapur, V.V., Thewissen, J.G.M., Das, D.P. and Tiwari, B.N. (2006) New Early Eocene cambaythere (Perissodactyla, Mammalia) from the Vastan lignite mine (Gujarat, India) and an evaluation of cambaythere relationships. Journal of the Palaentological Society of India, vol. 51, p. 101–110. 3. Clementz, M., Bajpai, S., Ravikant, V., Thewissen, J.G.M., Singh, I.B. and Prasad, V., 2011: Early Eocene warming events and the timing of terrestrial faunal exchange between India and Asia. Geology, vol. 39, p. 15–18. 4. Cooper, L.N., Seiffert, ER, Clementz, M., Madar, SI, Bajpai, S., Hussain, S.T. and Thewissen, J.G.M. (2014) Anthracobunids from the Middle Eocene of India and Pakistan are Stem Perissodactyls. PLoS ONE, 9(10), p.e109232, doi: 10.1371/journal.pone.0109232. 5. Rose, K.D., Holbrook, L.T., Rana, R.S., Kumar, K., Katrina, E.J., Heather, E.S.,Missiaen, P., Sahni, A. and Smith, T. (2014) Early Eocene fossils suggest that the mammalian order Perissodactyla originated in India. Nature Communications, 5 (5570), p. 1–9.

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NANNOFOSSIL IMPRINTS OF PALEOGENE TRANSGRESSIVE EVENTS IN INDIA Jyotsana Rai Birbal Sahni Institute of Palaeobotany, Lucknow-226007 E-mail: [email protected]

The transition from super hot Cretaceous to freezing Palaeogene climate and therein reasonably fast travel of Indian plate from equatorial tropics to buckling with Tibetan plate after subduction and engulfing the Tethys Sea, thus giving rise to lofty Himalayas, affected the oceanic current patterns and both fanua and flora drastically. These fast tectonic processes from 65Ma to 50Ma led to eustatic rise and in its response imprints could be seen in several areas of Indian subcontinent. The calcareous nannofossils being marine, tiny (2-10μm), photosynthetic belonging to golden brown algae, having fast turnover rate during Tertiaries are ideal as biostratigraphic markers and utilized in India also wherever the imprints of Palaeogene transgressions on Indian craton are recorded. After the global catastrophic late Cretaceous mass extinction around 65Ma in which over ninety nine percent coccolith species after gigantism died out. At the dawn of Palaeocene, new species evolved which grew exponentially in number and size during early Palaeogene. Massive release of greenhouse gasses at the beginning of the PETM occurred and the end of PETM was met with a very large sequestration of carbon dioxide in the form of methane, clathrate, coal and crude oil which reduced the atmospheric carbon dioxide. The beginning of the Eocene Epoch indicated increased amount of oxygen in the earth's atmosphere. At the end of the Middle Eocene Climatic Optimum, cooling and the carbon dioxide drawdown continued through the late Eocene and into the Eocene-Oligocene transition. In India, nannofossils are recorded from Upper Cretaceous and Lower Tertiary formations of Pondicherry, south India (Narasimhan, 1975); upper Late Maastrichtian/Danian age Subathu of Dharampur-Simla Himalaya (Jafar and Kapoor, 1988); K/T boundary species with Early Eocene nannofossils from Subathu Formation, Shimla Himalaya (Jafar and Singh, 1992); Cretaceous-Tertiary sequence of Khasi Hills, Assam (Narasimhan, 1963); Paleocene age Discoaster multiradiatus Zone from bore hole of Gopurapuram village northeast of Vriddhachalam area (Jain et al., 1983). Nannofossils are also recorded from early Ypresian age Jafarabad Formation and Lutetian to Priabonian age Belapur Formation of Bombay Offshore Basin (Saxena, 1996). K/Pg boundary and Paleocene to Oligocene age nannofossil zones were identified from Amalpuram, Palakollu wells of Krishna- Godavari Basin (Saxena, 2000). Precise LPTM boundary was marked in Vastan lignite mine of Cambay basin by nannofossil assemblage and negative carbon isotope excursion was noticed (Samanta et al., 2013a, b). Middle Eocene age nannofossil assemblages were known from several sections of Kachchh (Pant 57


and Mamgain, 1969); Sanu (Paleocene) and Bandah (Bartonian) of Kharatar well-C of Jaisalmer (Singh, 1998), Bartonian age nannofossils from Tanot well-1 (Rai et al., 2014); Rakhadi river section (Singh et al., 1980); Berwali stream (Singh, 1988); Lakhpat (Singh, 1978a, 1980a); Vinjhan-Miani (1978b, 1980b); Abhay-1 well of Bengal Basin (Singh, 1983); Rato Nadi section (Singh and Singh, 1987; 1991); Rachelo nala section (Rai, 1988; Jafar and Rai, 1994, Rai, 1997, Rai 2007); Babia Hill (Singh and Singh, 1986). Nannofossils are encountered from Late Eocene of Broach, (Pant and Mathur, 1973); Tarakeshwar area (Singh et al., 1978), near Surat Late Eocene outcrops of Ghalha Nala and Kusumbha Tal area containing nannofossils belonging to NP 20 Zone of Martini (1971);? Lutetian – Priabonian age nannofossils from Tarapur Shale of Dumas Well-A, Cambay Basin, Surat (Singh and Uddin, 2000); Late Eocene of Kopili Formation of Mikir Hills, Assam (Singh, 1979); Priabonain age nannofossils from Rewak Formation, South Garo Hills (Singh et al.,2015); Meghalaya; Lutetian to Priabonian age nannofossils from Chanasma wells of Mehsana block, Cambay Basin (Singh et al.,1998). The early Eocence nannofossils with reworked Cretaceous –Paleocene taxa are also seen in Ladakh area. Uninterrupted Late Eocene (Priabonian) and Early Oligocene (Rupelian) sediments with boundary could be found in Meghalaya, northeastern India as Priabonian is hiatus on land in Kachchh and Jaisalmer areas of western India. References: 1. Jafar, S.A. and Kapoor P.N. (1988) Late Maestrichtian-Danian nannoplankton from basal Subathu of Dharampur, Simla Himalaya. India. palaeogeographic implications. Palaeobotanist, 37(1): 115-124. 2. Jafar S.A. and Rai J. (1994) Late Middle Eocene (Bartonian) calcareous nannofosils and its bearing on coeval post–trappean transgressive event in Kutch basin, western India. Geophytology, 24(1): 23–42. 3. Jafar, S.A. and Singh, O.P. (1992) K/T boundary species with Early Eocene nannofossils discovered from Subathu Formation, Shimla Himalaya, India. Curr. Sci., 62 (5), 409-413. 4. Jafar S.A., Rai J. and Vimal K.P. (1985) Integrated nannoplankton-Larger foram biostratigraphy and facies of Late Eocene rocks exposed around Tarakeshwar town, Surat. Gujarat. 5th Conv. Indian Assoc. Sedimentol. Hyderabad (Abst.), 4648. 5. Jain K.P., Garg R. and Joshi D.C. (1983) Upper Palaeocene calcareous nannoplankton from Vriddhachalam area, Cauvery Basin, Southern India. Palaeobotanist, 31(1), 69-75. 6. Narasimhan, T. (1963) Coccolithophorids and related nannoplanktons from the Cretaceous-Tertiary sequence of Khasi Hills,Assam. J.Geol.Soc.India. 4, l09-115. 7. Narasimhan T. 1975 Nannoplanktons from Upper Cretaceous and Lower Tertiary formations of Pondicherry, south India- II: pp.207-208 In: Venkatachala B.S. and

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Sastri V.V. (Eds.) -Proc.4th Indian Colloq. Micropal. Strat. Dehradun 1974-75, Indian Institute of Petroleum Exploration, Oil Nat. Gas Commission, Dehradun. 8. Pant, S.C. and Mamgain, V.B. (1969) Fossil nannoplankton from the Indian subcontinent. Rec. Geol. Surv. India, 97 (2), 108-128. 9. Pant S.C. and Mathur U.B. (1973) Fossil nannoplankton from Eocene of Broach. Gujarat, India. Rec.Geol. Surv. India, 105(2), 209-216. 10. Rai, J. (1988) Calcareous nannoplankton from Eocene of Kutch, western India. Unpublished Ph.D. Thesis, Lucknow University, Lucknow, 316p. 11. Rai J. (1997) Scanning–electron microscopic studies of the Late Middle Eocene (Bartonian) calcareous nannofossils from the Kutch Basin, western India. J. Palaeont. Soc. India, 42, 147 – 167. 12. Rai, J. (2007) Middle Eocene calcareous Nannofossil Biostratigraphy and Taxonomy of on land Kutch Basin, western India. Palaeobotanist, 56, 29-116. 13. Samanta, A., Sarkar, A., Rai, J. and Rathore, S. S. (2013a) Late Paleocene-Eocene carbon isotope stratigraphy from a near – terreastrial tropical section and antiquity of Indian mammals. Journal of Earth System Sciences, 122 (1), 163- 171, 14. Saxena, R.K. (1996) Calcareous nannoplankton biochronostratigraphy of Bombay Offshore Basin. Contrs. 15 Ind. Colloq. Micropal. Strat. Dehradun, 1986 (Eds. Pandey, J., Azmi, R.J., Bhandari, A. & Dave, A.) 723 – 732. 15. Samanta, A., Bera, M. K., Ghosh, R., Bera, S., Filley, T., Pande, K., Rathore S.S., Rai, J. and Sarkar, A. (2013b) Do the large carbon isotopic excursions in terrestrial organic matter across Paleocene–Eocene boundary in India indicate intensification of tropical precipitation? Palaeogeography, Palaeoclimatology, Palaeoecology, 387, 91–103. 16. Rai, J., Singh, A. and Gulati, D. (2014) Bartonian age calcareous nannofossil biostratigraphy of Tanot well-1, Jaisalmer basin and its implications. Journal of the Palaeontological Society of India, 59(1), 29-44. 17. Saxena, R. K. 2000 Calcareous nannofossil datum levels in the P{aleogene Shale sections of Krishna-Godavari Basin, India, Proceedings of XVI Indian Colloquium on Micropaleontology and Stratigraphy, NIO, Goa, Bull. ONGC, 37 (2): 161-172. 18. Singh, P. (1978a) A note on the Late Middle Eocene nannofossils from Lakhpat, Kutch. Curr.Sci., 47(3), 87-88. 19. Singh, A., Rai, J. and Garg, R. (2015) Late Eocene (Priabonian) age nannofossils from Rewak Formation, Garo Hills, northeastern India. (abstract published in this volume). 20. Singh M.P. and Singh P. (1987) A note on the geology and micropalaeontology of the Rato Nadi Section, Kutch. Gujarat State, India. Geosci. J., 8(1&2), 201-204. 21. Singh, P. (1978b) A note on the Late Middle Eocene nannofossils from the Vinjhan-Miani Area, Kutch. Curr. Sci., 47(2), 53-54.

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22. Singh, P. (1979) Calcareous nannoplankton from the Kopili Formation of Mikir Hills, Samkherjan Area, Assam. Bull. Oil Nat. Gas Commission, Dehradun 16(2), 75-85. 23. Singh, P. (1980a) Late Middle Eocene calcareous nannoplankton from Lakhpat, Kutch, Western India. Geosci. J., 1(1), 1-14. 24. Singh P. 1980b Late Middle Eocene calcareous nannoplankton and palaeogeographic remarks on Vinjhan-Miani Area, Kutch. Gujarat.Geosci. J., 1(1): 15-29. 25. Singh, P. (1983) Eocene calcareous nannoplankton from the Abhay-l Well, Bengal Basin with palaeoceanographic remarks. 1st Int. Conf. Paleoceanography, Zürich (Abst.), 60. 26. Singh, P. (1988) Late Middle Eocene calcareous nannoplankton from Berwali river section. Kachchh. India. Geosci. J., 9(2), 231-246. 27. Singh, P. (1998) Calcareous nannoplankton and foraminiferal biostratigraphy of upper Cretaceous and Paleogene subsurface sequences of Kharatar well– C, Jaiasalmer Rajasthan. Geosci. J., 19(2), 145 - 169. 28. Singh, P., Porwal, D.K. and Uddin, I. (1998) Microfauna and calcareous nannoplankton from the subsurface Tertiary sequence of Chanasma wells B and C, Mehsana Block, Cambay Basin, Gujarat. Geosci. J., 19(2): 87 – 99. 29. Singh, P. and Singh, M.P. (1986) Late Middle Eocene calcareous nannoplankton from Babia Hil, Kutch. Gujarat. India. Geosci. J., 7(2), 145-162. 30. Singh, P. and Singh M.P. (1991) Nannofloral Biostrqtigraphy of the Late Middle Eocene strata of Kachchh region Gujarat state, India. Geosci. J., 12(1), 17 – 51. 31. Singh, P., Rastogi, K.K. and Vimal, K.P. (1978) A note on the Late Eocene nannofossils from Tarkeshwar. Gujarat. Curr. Sci., 47(10), 346-347. 32. Singh, P., Singh, M.P., Mathur, D.N. and Srivastava, R.N. (1980) Late Middle Eocene calcareous nannoplankton from Rakhadi River Section, Harudi, Kutch. Curr. Sci., 49(5), 172-176. 33. Singh, P. and Uddin, I. (2000) Calcareous nannoplankton from the Subsurface of the Tertiary Sequence of Dumas well– A, Cambay Basin, Gujarat. Proceed. XVI Ind. Colloq. Micropal. Strat., NIO, Goa, Bull. ONGC Ltd., 37 (2), 219 – 224.

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EOCENE FORAMINIFERA FROM THE NAGA-MANIPUR HILLS OF INDO-MYANMAR RANGE, NORTHEAST INDIA: FRESH INSIGHTS Kapesa Lokho Wadia Institute of Himalayan Geology, 33 GMS Road, Dehra Dun- 248 001, India E-mail: [email protected]

Eocene foraminifera from the Indo-Myanmar Range (IMR) of northeast India remain poorly studied till date. A brief review of the Eocene foraminifera is enumerated from north to south of the IMR of northeast India. Late early Eocene foraminifers are reported from the Yinkiong Formation, Siang district of Arunachal Pradesh consisting of Nummulitesatacicus, N. dandotica, N. daviesi, N. laminose, N. globulus, N. spinosa. In Nagaland, late Eocene foraminiferal markers such as Cribrohantkeninainflata, Hantkeninaalabamensis and other planktonic and benthic foraminifers along with pteropods were reported from the Upper Disang Formation (UDF). So far there are no reports of Eocene foraminifera from Manipur although there are exposures of the Disang Group. Micro-foraminiferal linings are known from the UDF of Manipur. In Mizoram and Tripura, the southernmost part of the IMR in the NE India, there are no reports of Eocene foraminifera but Miocene foraminifera are studied by few workers from the Surma Group as it is the oldest sedimentary succession present in the region. In this study, Eocene foraminifers and associated fossils are described from new localities of Naga-Manipur Hills from the Disang Group. Correlative studies are made with the better documented coeval sediments of northwest Himalaya and western India to build up a broader picture of the holistic view of the evolution of the Himalaya and the closure of the Tethys seaway.

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THE OLIGOCENE CORALS HAD CIRCUMTROPICAL DISTRIBUTION Patrali Sinha and Kalyan Halder Department of Geology, Presidency University, 86/1, College Street, Kolkata- 700073 E-mail: [email protected]; [email protected]

It has been known for long that the Oligocene rocks of Kutch, Gujarat yield corals. But, the corals had not been systematically reported. In our endeavour to make a comprehensive systematics of the corals from the Oligocene of Kutch we have so far identified 20 species belonging to 12 genera from a single locality. Almost all the species are new whereas nearly all the genera were known from Tethyan Europe and Iran. An analysis of biogeographic distribution of the Oligocene corals of the world reveals strong specific endemism whereas large generic pandemism. Three biogeographic provinces are identified here based on this distribution: Western Indian Province (WIP) represented by Kutch, Mediterranean-Iranian Province (MIP) consisting of Greece, Italy and Iran, and CaribbeanProvince (CP) composed of Antigua, Puerto Rico and Venezuela. Different basins within a province show some specific similarity whereas specific provincialism is nearly absolute. Genera show wide distribution - WIP shows 75% similarity with MIP and 44.40% with CP; CP has 67% similarity with MIP. On the contrary, much fewer generic data from subtropical western Atlantic state of USA, Washington, show significant endemism. Data from eastern Pacific California, still poorer, have strong similarity with that from Washington. Dispersal beyond tropics was apparently limited. The tropical affinity, and wide and rapid dispersability of the Oligocene corals is evident from this distribution pattern. Generic exchange between WIP and MIP, both belonging to the Tethyan Realm, has been known for other organisms (Harzhauseret al., 2002). Affinity of these provinces with CP is worth noticing. This similarity reflects the presence of a trans-Atlantic current during the Oligocene. Significant similarity in other benthic organisms between these provinces has been documented (Harzhauseret al., 2002). Near global distribution of the coral genera also evinces protracted planktotrophic larval ontogeny. However, endemism in the species level indicates rapid evolution. This distribution pattern having tropical yet wide longitudinal extent and provincialism of species resembles the present day distribution of corals. It reflects that the scleractinian coral biology had already attained modern aspects in the Oligocene. Reference: 1. Harzhauser, M., Piller, W. E. and Steininger, F. F. (2002) Circum-Mediterranean Oligo-Miocene biogeographic evolution - the gastropods’ point of view. Palaeogeography, Palaeoclimatology, Palaeoecology, 183, 103-133.

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IMPLICATION OF THE OCCURRENCE OF MINUTE BIOTIC BODIES ON CONJOINED TESTS OF NUMMULITES AFF. NUMMULITESACUTUS (SOWERBY) IN THE SUBSURFACE EOCENE OF CAUVERY BASIN, INDIA Sanjay Kumar Mukhopadhyay Ex-Palaeontology Division I, Geological Survey of India, 15, Kyd Street, Kolkata 700016 E-mail: [email protected]

A shaly marl core from subsurface Cauvery Basin, south of Pondicherry, India provided upper Middle Eocene assemblage comprising Nummulitesaff. Nummulitesacutus (Sowerby), Nummulitessp, Assilina sp, Pellatispira sp, Operculinasp. and DiscocyclinajavanaVerbeek, of which Nummulites aff. acutusis distinct with few anomalous distorted tests and conjoined tests, on which minute biotic bodies attach firmly. Present study focuses on these tiny bodies and their possible cause of development because such attachment is hitherto unknown in adult Nummulites. In aconjoined entity, two megalospheric adult individuals of the species fuse at their apertures developing a contact zone while a distorted individual is asymmetric often with swerved peripheral margin. Both contain sporadic lime deposit, numerous cavities, and minute bodies occurring either as discrete featureless globular form (~1 µm), acluster of many globular forms or as nepionic Nummulites (150-200 µm) containing rudimentary granulations, septal filaments, planispiral whorls, septa, alar prolongations, involute spiral sheets and quadrangular chambers. Exclusive attachment of similar looking, intact and well-preserved bodies on anomalous tests indicate in situ development of the former and not by transportation. Minute bodies in varying size and features reflect gradational development representing different growth stages. Size resemblance of a tiny body and the initial chamber of a nepionic form points for a linkage in between. These minutenepionic bodiesby possessing similar features as of associated adults and due to occurring in aperture, chamber, contact zone and cavities of conjoined tests, possibly had hereditarily link with the adults. The anomalous tests being restricted to Nummulitesaff. acutusare difficult to explain by environmental stress. Since megalospheric tests represent the species, megalospheric adults develop conjoined tests, and minute bodies associate with only anomalous megalospheric representatives, a genetic link is presumed between conjugation of megalospheric tests and development of minute bodies. This incidence closely resembles plastogamy in modern smaller benthic foraminifera. Taking a cue from plastogamy, the minute bodies are considered fossilized juveniles. A distorted adult test with attached minute bodies represents separated form from conjugation, and characters on attached surface suggests that conjoining involved fusion of only outer whorls of the adults. Test distortion was a voluntary phenomenon for best union while fusion of apertures facilitated mingling of protoplasmic material for the generation of offspring; lime deposit served as adherence during conjoining, and cavities and pores as 63


passageways for the juveniles. A tiny globular body seems single chambered resembling modern brood. Nepionic forms indicate longer stay of juveniles with adults before release into ocean. Nummulites are the oldest known and most widely studied largest group of foraminifera, yet their life cycle is not completely documented. Prevalence of alternation of sexual and asexual generations is postulated from dimorphic forms in extinct and modern Nummulites. Laboratory culture of modern Nummulitesvenosus documented only asexual reproduction. Earlier postulations of sexual reproduction in certain extinct species in conjoined state (Mukhopadhyay, 2003, 2007) lacked unequivocal support of associated juveniles whose find ascertains that sexual reproduction prevailed in extinct Nummulitesaff. acutus. This study suggests that fossil record could be complementary to laboratory culture to know life cycle in Nummulites. References: 1. Mukhopadhyay, S. K. (2003) Plastogamy and its early morphological indication in Nummulitesboninensis Hanzawa from the Middle Eocene of Cambay Basin, India. Revue de Paléobiologie, 22, p. 231– 242. 2. Mukhopadhyay, S. K. (2007) Conjoined tests of Nummulites from the Paleogene of the Cambay Basin, India and their possible origin: Journal of Foraminiferal Research, v. 37, p. 41–45.

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PALYNOLOGY AND DEPOSITIONAL ENVIRONMENT OF NINIYUR FORMATION (EARLY PALAEOCENE), CAUVERY BASIN, SOUTHERN INDIA M. R. Rao1 and J. Madhavaraju2 1

Birbal Sahni Institute of Palaeobotany, 53, University Road, Lucknow- 226007 (India) Estaction Regional del Noroeste Instituto de Geologia, Universidad National Autonoma de Mexico, Hermosillo, Sonora-83000, Mexico E-mail: [email protected]; [email protected]

2

The Palaeocene rocks (Niniyur Formation) overlying the Ariyalur Group of Ariyalur area (Tamil Nadu) are important constituents of the Early Tertiary succession of the Cauvery Basin. The Niniyur Formation of Cauvery Basin is well exposed at Adnankurichchi and Periakurichchi limestone mines in the Perambalur District of Tamil Nadu. The lithology mainly consists of limestone, silty shale, marl and calcareous sandstone. For the first time, palynological data has been recorded from Periakurichchi Limestone Mine Quarry (Niniyur Formation), Cauvery Basin. The total assemblage consists of 21 genera and 29 species of algal remains (4 genera and 6 species, including dinoflagellate cysts), pteridophytic spores (2 genera and 2 species) and angiosperm pollen (12 genera and 16 species). Reworked elements (3 genera and 5 species) have also been recorded. The significant genera include, Lygodiumsporites, Palmidites, Liliacidites, Proxapertites, Retitrescolpites, Lanagiopollis, Paleosantalaceaepites and Clavaperiporites. The palynological data depict a tropical-subtropical climate during the time of sedimentation. Palynomorphs belonging to terrestrial (Lanagiopollis, Tricolporopollis, Retitrescolpites, Clavaperiporites and Monoporopollenites), fresh water swamp and water edge (Azolla, Zygnema, Lygodiumsporites and Cyathidites), coastal (Liliacidites, Palmidites and Retimonosulcites), mangrove (Paleosantalaceaepites and Warkallipollenites) and marine (Achomosphaera and Lingulodinium) elements have been identified. The presence of dinoflagellate cysts and mangrove elements in the palynoassemblage indicate that the deposition took place in a shallow marine environment consistent with the presence of algae, foraminifera, ostrocoda and marine mollusca. The studied sequence has been assigned as Early Palaeocene age on the basis of palynomorphs viz., Proxapertites, Retimonosulcites, Lanagiopollis, Retitrescolpites, Tricolporopollis and Retistephanocolpites. Known benthic and planktonic foraminifera also corroborate this age determination (Malarkodi and Nagaraja, 1979).

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CORALLINE ALGA SPOROLITHON FROM THE LATE PALAEOCENE LIPA BLACK SHALE FORMATION OF THE MITHAKHARI GROUP, MIDDLE ANDAMAN K. M. Wanjarwadkar1 and P. Kundal2 1

Department of Geology, Govt. Institute of Science, Caves Road, Aurangabad-431 004 Department of Geology, RTM Nagpur University, Law College Square, Nagpur-440 001 Email: [email protected]; [email protected]

2

Sporolithon (Division: Rhodophyta, Order: Corallinales, Family: Sporolithaceae) is an important taxon of nongeniculate coralline algae and ranges from the Aptian to the Recent. The present paper records eight species of Sporolithon, namely Sporolithon chamorrosum (Johnson) Ghosh and Maithy, S. hemchandri (Sripada Rao) comb. nov., S. microsporum sp. nov, S. myriosporum (Johnson) comb. nov, S. nummuliticum (Rothpletz) Ghosh and Maithy, S. oulianovi (Pfender) Ghosh and Maithy, S. prisiense (Lemoine) Ghosh and Maithy and S. ranikotensis (Narayana Rao) Ghosh and Maithy from the late Palaeocene (Thanetian) Lipa Black Shale Formation belonging to Mithakhari Group (= Baratang Formation) of Middle Andaman. In the studied material species of Sporolithon occur in association with Jania, Corallina, Lithothamnium and dasycladacean algae along with other biota such as corals, foraminifers indicating that the sediments were deposited under shallow water reefal environment within the depth of 30m. Out of the reported species Sporolithon ranikotensis and S. hemchandri respectively comes from Palaeocene and lower Eocene of Assam suggesting Tethyan affinities.

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HYDROCARBON SOURCE POTENTIAL AND DEPOSITIONAL CONDITIONS OF GURHA LIGNITE DEPOSITS (BIKANER BASIN), RAJASTHAN, WESTERN INDIA R. P. Mathews1, Alpana Singh1, S. Mahesh1, V. P. Singh1, B. D. Singh1 and Suryendu Dutta2 1

Birbal Sahni Institute of Palaeobotany, 53-University Road, Lucknow - 226 007, India 2 Indian Institute of Technology Bombay, Powai, Mumbai – 400 076, India E-mail: [email protected]

The lignite bearing sequence of Gurha mine belongs to the Marh Formation (Palaeocene-Eocene) of Bikaner Basin in the western Indian state of Rajasthan. Multidisciplinary study (organic petrography, palynofacies and Rock-Eval pyrolysis analyses) has been carried out on lignites/shales to understand the hydrocarbon source potential and the depositional conditions of about 18 m thick composite seam. The palynofacies analysis indicates the dominance of phytoclasts and sub-dominance of amorphous organic matter. The petrographic study reveals the dominance of huminite group of macerals (followed by inertinites and liptinite macerals), mainly represented by telohuminite (structured: textinite+ulminite) and detrohuminite (detritus: attrinite + densinite). The huminite reflectance (Rr mean) value of lignites (av. 0.26%) as well as low Rock-Eval Tmax values (av. 419°C) for the seam, suggest lignite is of ‘Low Rank B’ (ISO standard: 7404-5) and of immature nature. The hydrogen index (HI) of these deposits varies from 162 to 546 mg HC/g TOC. The high total organic carbon (TOC: up to 44.32%) and a mix of Type II and III kerogens indicate the potential of this lignite deposit to produce a mix of oil and gaseous hydrocarbon on maturation. The visual kerogen analysis (both palynofacies and organic petrographic) also shows consistency with the Rock-Eval pyrolysis data. The type of huminite suggests mixed vegetal source (woody forest vegetation, herbs and shrubs) for the peat-forming biomass. The Gelification Index (GI) vs. Tissue Preservation Index (TPI) plot indicates the accumulation of lignite-forming peat in limnotelmatic depositional conditions. The extrapolation of Ground Water Index (GWI) and Vegetation Index (VI) indicates accumulation of the peat precursors under ombrotrophic to mesotrophic hydrological regimes. The extrapolation of the palynofacies data on Tyson’s Amorphous Organic Matter-Phytoclast-Palynomorphs (APP) diagram depicts five palynofacies fields; suggesting marginal dysoxic-anoxic conditions of deposition for the studied lignite sequence.

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RECOVERY OF A MARINE FOOD CHAIN FROM THE PALAEOCENE CARBONATE SEDIMENTS OF KARASUR FORMATION (PONDICHERRY AREA) OF CAUVERY BASIN Amit K. Ghosh, Abhijit Mazumder and Arindam Chakraborty Birbal Sahni Institute of Palaeobotany 53 University Road, Lucknow – 226 007, INDIA E-mail: [email protected]; [email protected]; [email protected]

Lithological variations and fossil assemblages of the marine Cretaceous–Palaeocene (Danian) self succession of the Cauvery Basin, southern India has been a matter of attraction for the geoscientists and palaeontologists since the mid-nineteenth century. As a matter of fact, it has provided world class data on the invertebrates from the mid Cretaceous to Palaeocene (Danian) successions, which are available in a considerable number of publications. These rocks are exposed in isolated patches along the east coast of southern India in different areas of Ariyalur, Vriddhachalam and Pondicherry. Samples for the present study have been collected from the Tondamanattam limestone quarry section located about one km north of Sedarappatu Village near Pondicherry that has been designated as a reference partial section of Karasur Formation. The Karasur Formation conformably overlies the Mettuveli Formation and in turn is conformably overlain by Manaveli Formation. A Palaeocene age for the Karasur Formation has been suggested earlier based on the study of planktic foraminifera. Thin section analysis of the limestone samples collected from the Karasur Formation yielded well preserved coralline red algae belonging to families Hapalidiaceae, Corallinaceae and Sporolithaceae. The benthic foraminifers are represented by nummulitids, rotaliines and textularids. The bryozoan fragments are assignable to the genus Ceriopora. Apart from that echinoid spines are also very common as observed in thin sections. An attempt has been made to analyse the trophic subdivisions of the carbonate components based on the feeding strategies of the different biogenic components present in the studied carbonate facies.

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KEROGEN TREND ANALYSIS FOR DEPOSITIONAL ENVIRONMENT INTERPRETATION AND HYDROCARBON POTENTIAL OF SEDIMENTS FROM MATASUKH LIGNITE MINES, RAJASTHAN THROUGH PALYNOFACIES STUDIES Mahesh. S1 and Hukam Singh2 1

2

498-171/2, Serv Sneh Kunj, 8 Faizabad road, Lucknow Birbal Sahni Institute of Palaeobotany, 53 University Road, Lucknow, E-mail: [email protected]

Quantitative and qualitative analyses of systematically collected lignite and associated lithological samples from Matasukh lignite mine were carried out for Kerogen typing and to determine the hydrocarbon potential of the sedimentary sequence consisting of shale, lignite and clay. These early Eocene lignite deposits in the Matasukh mine of Nagaur district are associated with Marh Formation of Rajasthan. The dataset retrieved from the collected samples was used in categorizing the Kerogen types from the respective sediment sequence which was further extrapolated on models to interpret the depositional conditions. The derived organic matter is rich in Amorphous Organic Matter (AOM) and phytoclasts where in, majority of the AOM are terrestrially derived. Even though the spores and pollen were encountered in moderate percentages, they exhibit excellent preservation. Two palynofacies were defined through the cluster analysis (Manhattan type) based on the quantitative statistics. Palynofacies-I is dominated by AOM, sub-dominated by phytoclasts and vice versa in Palynofacies-II. The comprehensive visual analyses reveal that the lignite bearing sedimentary sequence is characterized by Type-II Kerogen (AOM+phytoclasts). Majority of the Thermal Alteration Index (TAI) of the retrieved organic matter has revealed that the sediments are early matured-matured. The plotting of data on AAP diagram indicates the deposition of these sediments in a restricted environment and the qualitative study of palynofacies component shows a proximal to distal trend of deposition.

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SIGNATURES OF PALEOGENE TECTONICS AND REVERSAL OF STRESS REGIME ALONG KACHCHH MAINLAND FAULT, KACHCHH, GUJARAT P.K. Singh Geological Survey of India, NR, Lucknow E-mail: [email protected]

Tectonic framework of Kachchh Peninsula is governed by the east-west trending major faults of Mesozoic Era viz. Nagar Parkar Fault, Island Belt Fault, Kachchh Mainland Fault (KMF) and Katrol Hill Fault from north to south. Origin of these faults is attributed to the extensional regime of stress that prevailed before the collision of the Indian Plate with the Eurasian Plate. After this collision in early Tertiary Period, the stress condition changed into compressional regime (Biswas, 1987). Numbers of transverse faults have been reported across the master faults which are very active and play an important role in the recent seismic activities in the Kachchh region. There are several evidences of stress regime recorded from the area. A number of normal faults have been recorded from the rocks of Mesozoic formations indicating an extensional regime. The change in the stress regime after the collision of the Indian Plate in Early Tertiary Period resulted into the formation of reverse faults, transverse faults and drag folds along the master faults of the area. These features are recorded from different sections of the area along the Kachchh Mainland Fault, which is one of the most seismogenically active faults of Kachchh. Tertiary rocks are exposed on the flanks of almost all the Mesozoic outcrops in Kachchh region. Extensive laterization after the Deccan volcanism under tropical conditions followed by deposition of thick Tertiary sediments along the coastal strip of Kachchh Mainland is the typical phenomena of the Kachchh region during Palaeogene Period. The Palaeogene rocks in the Kachchh basin are represented by the rocks of the Matanomadh Formation (Paleocene), Kakdinadi Formation (Lower Eocene), Fulra Formation (Middle to Upper Eocene), Maniyara Fort Formation (Oligocene) and Kharinadi Formation (Oligocene to Lower Miocene) rocks which are overlain by thick sequence of rocks of the Gaj Formation of Miocene age (GSI, 2001). The dominant rock types of the Palaeogene units are lateritic conglomerate, fossiliferous limestone, shale and siltstone whereas the overlying Gaj Formation is represented mainly by gypseous shale and marl. The area was continuously under tectonic instability at the time of deposition of Tertiary units therefore the signatures of the events are recorded in these sedimentary sequences. The compressional stress regime is manifested in the form of several reverse faults recorded in the Tertiary and Quaternary Period of rocks. In the north of Khirsara village, to the north of the Kachchh Mainland Fault, drag folds are recoded from the Tertiary horizons. These observations also indicate that the mesoscopic folds recorded at

70


several places in Kachchh exhibit the characteristics of fault-propagation folds. When alternate layers of relatively more ductile shales and stiffer sandy layers of the region are subjected to compression several folds and thrust zones are developed which are reported from various parts of the Kachchh basin. Several structures resulted on account of compressive stresses such as arching of beds and formation of contractional wedges has been recorded near the margins of highlands (Karanth and Gadvi, 2007). Post Tertiary tectonic activities due to compression also resulted into tilting of Tertiary sequences along the Kachchh Mainland Fault. Tilting of Conglomerate beds of Palaeo-Eocene Epoch near Amardi village is recorded near the Kachchh Mainland Fault. References 1. Biswas, S.K. (1987) Regional tectonic framework, structure and evolution of the western marginal basins of India. Tectonophysics, 135, 307-327. 2. GSI (2001) Geology and Mineral resources of Gujarat, Daman and Diu. GSI, Miscellaneous Publication, 30, Part XIV, 102p. 3. Karanth, R.V. and Gadvi, M.S. (2007) Structural intricacies: emergent thrusts and blind thrusts of Central Kachchh, western India. Curr. Sc., 93, 1271-80.

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HYDROCARBON SOURCE ROCK OF THE KOPILI FORMATION (EOCENE), MEGHALAYA Y. Raghumani Singh, Guneshwor Tongbram and Akham Bijayalaxmi Devi Department of Earth Sciences, Manipur University Imphal-795 003, India E-mail: [email protected]

We analyzed the palynofacies distribution and Rock Eval in Kopili Shale (lower section) from Umphyrluh, Meghalaya to support reconstruction of the hydrocarbon source potential. The present palynotaxa are mainly composed of Dinoflagellate cysts viz. Operculodinium centrocarpum, Operculodinium major, Polysphaeridium zoharyi, Polysphaeridium subtile, Diphyes colligerum. The source rock potential of Kopili Shale recorded different types of organic matters such as charcoal, partly biodegraded terrestrial organic matter, amorphous, black debris, spore and pollens (dinoflagellates). Based on the palynofossils investigations, it is inferred that the sediments were deposited under a shallow marine environment having inner shelf (relatively deeper) and open marine influence and absence of brackish water environment. Rock-Eval and TOC analysis of the Kopili Shale indicates that all the samples have poor organic richness (TOC

A part 1 abstract.cdr

A part 1 abstract.cdr

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