6th International Symposium of the International Geoscience Programme (IGCP) Project- Abstracts
9
Reconstruction of the tectonic terranes in the Myanmar territory Hla Hla AUNG
Myanmar Earthquake Committee, MES Building, Hlaing University Campus, Hlaing Township, Yangon, Myanmar; e-mail:
[email protected]
Myanmar represents an evolving continent of two crustal formation histories consisting of theBurma plate and the Indochina plate. The Burma plate consists of three distinct lithotectonic entities of: 1) a continental fragment; 2) a subduction-related accreted complex and 3) a coastal area. Eastern Myanmar that is western continuation of Indochina plate is composed of three tectonostratigraphic terranes. Biostratigraphic correlation between the known distribution of dominant Mesozoic representatives of Monotis, Halobia, and Daonella fauna and microfossil assemblages of Triassic age from Myanmar (Figs 1, 2) are made with those from neighboring countries of SE Asia to get estimated palaeogeographic position and reconstruction of tectonic terranes for Myanmar (Fig. 3). These terranes may have originated in Gondwana in Paleozoic. Each tectonic terrane has been separated by three suture zones of the Paleo-, Meso- and NeoTethys. They are: 1) The Than Lwin Belt in the easternmost part of Myanmar, which is a tectonic linkage between Inthanon Zone of West Thailand and Changning-Menglian belt (West Yunnan); 2) Shan Boundary Belt of Meso-Tethys suture in the western edge of Indochina plate; 3) Rakhine Western Ranges (Rakhine-Andaman-Nicobar belt) of NeoTethys suture at the westernmost part of Myanmar. These accretionary episodes which ended in Early Tertiary, have been followed by post-accretionary deformation of strikeslip faulting of the Sagaing Fault in Myanmar; West Andaman Fault and Sumatra Fault System in Sumatra; spreading in Andaman back-arc basin.
Fig. 1. The known distribution of dominant Mesozoic representatives of Monotis, Halobia, and Daonella fauna in Shan Massif terrane and correlation with those of neighboring terranes
Fig. 2. Biostratigraphic correlation of micro- and macro-forminifera of Myanmar with major palaeogeographic provinces of SE Asia
Fig. 3. The sequential evolution cross-sections are derived from available data of the published literatures
References 1.H.H. Aung: 1987. Geological Study of Pathi Chaung Granite as an aid to Terrane Analysis M.Sc Thesis(unpublished), University of Yangon,.
Tectonotratigraphic
2. F.Bender, 1983. Geology of Burma. Gebruder Borntraeger , Berlin Stittgart, Germany 3. J.R.Curray, 2005. Tectonics and history of the Andaman Sea region. J. Asia Earth Sci. XX pp1-42 4. A.Y..Le Dain, P. Tapponeir and P.Molnar, 1984. Active faulting and Tectonics of Burma and Surround regions.J.Geophys.Res.89(13)453-472 5. G.P.Gorshkov, 1959.The Problematic seismotect-onic and seismic zoning in the Territory of Union of Burma , Byull.Sovj.Seim. 12(in Russ.) 6. B.T. Haq,1981. Metallogenic Provinces and Prospects of Mineral Exploration in Burma,Contrib. Burmese Geol.1(1) 1-16. 7. N.Htay,2008.Personal Communication on Occurrence of Gabbros,volcanics and ophiolites in the east of Than Lwin River.
8. Mckenzi,D. & Scalter,J.G.1971. The Evolution of the Indian Ocean since the late Cretaceous Geophy.J.R.astr.Soc.24,437-528. 9. D.A.Pivnik et al,1999. Polyphase Deformation in Fore-arc/Back-arc Basin, Salin Subbasin, Myanmar (Burma), AAPG Bull 82(10) 1837-1858. 10. C.Rangin,1996-1999.Deformation of Myanmar, Results of GIAC Projects, GIAC Conf. (Yangon,Myanmar) 11.P.Tapponier,G.Peltzer,A.Y.E.Dain,R.Armijo,and P.Cobbold,1982 Propagating extrusion tectonics in Asia:new insight from simple experiment plasticene.Geology,v.10,p.611-616 12. Vigny et al. 2003. GPS network motion on Sagaing fault Myanmar. Trans.Suppl.83,
