Fusulinids from the Lower Permian Chili Formation of ...

ISSN 08695938, Stratigraphy and Geological Correlation, 2013, Vol. 21, No. 4, pp. 408–420. © Pleiades Publishing, Ltd., 2013. Original Russian Text © E.Ja. Leven, M.N. Gorgij, 2013, published in Stratigrafiya. Geologicheskaya Korrelyatsiya, 2013, Vol. 21, No. 4, pp. 78–90.

Fusulinids from the Lower Permian Chili Formation of the Rahdar Section, Kalmard Block, Central Iran E. Ja. Levena and M. N. Gorgijb a

Geological Institute, Russian Academy of Sciences, Moscow, Russia email: [email protected] bDepartment of Geology, Faculty of Sciences, University of Sistan and Baluchestan, Zahedan, Iran Received March 19, 2012; in final form, July 3, 2012

Abstract—Fusulinids from the Chili Formation are studied in the Rahdar section of the Kalmard block west of the town of Tabas, Central Iran. The Kalaktash and Halvan fusulinid complexes are revealed in the section. The location of the Halvan complex over the Kalaktash one confirms its relatively younger (Late Sakmarian– Early Artinskian) age. The Halvan complex was previously considered to be Asselian. Three new species (Parazellia rahdarensis, Nonpseudofusulina bozorgniai, and Eoparafusulina rahdarensis) and one new subspe cies (Benshiella khorasanensis compacta) are described. Keywords: stratigraphy, fusulinids, Permian, Iran DOI: 10.1134/S0869593813040060

INTRODUCTION The Rahdar locality is situated in the small Kal mard block clamped between the larger Posht–Badam block in the west and the Tabas block in the east (Fig. 1). As in other sections of the Kalmard block studied before (Leven and Gorgij, 2007, 2009, 2011; Leven et al., 2011), the Permian rocks are characterized by undisturbed bedding and overlap the Lower Carbonif erous rocks with parallel unconformity (Fig. 2). The fusulinids of interest to us are concentrated in the Chili Formation, the lower of four Permian formations. Several fusulinid species from the Rahdar locality are confined precisely to this formation and were described by Davydov and Arefifard (2007). Fusulin ids from the reviewed formation have now been stud ied in detail. They belong to the Kalaktash and Halvan complexes. Originally (Leven and Gorgij, 2009, 2011), the Halvan complex was found in the clasts of conglobreccias from the Tangale–Mokhtar and Sang–Variz sections (Halvan Mountains north of the Kalmard block). Conglobreccias are restricted to the basement of the Sartaht Formation and lie on the Chili Formation with fusulinids of the Kalaktash complex. The age of the latter was identified as Sakmarian, whereas the Halvan complex was dated as Asselian with some doubts. This was based on the great similar ity of the representatives of the Parazellia, Nonpseudo fusulina, and Globifusulina genera found in it with the species from the Asselian Stage of the Urals. Later, a similar fusulinid community was revealed in the upper part of the Chili Formation in the Darin locality,

where it gives way to the Kalaktash community (Leven et al., 2011). This finding indicated that (1) the age of the Halvan complex is younger than that of the Kalaktash complex and is not Asselian, but may be Late Sakmarian or Early Artinskian; (2) conglobrec cias from some sections in the basement of the Sarta kht Formation were formed owing to destruction of the top of the Chili Formation; and (3) fusulinids of the Halvan complex ascribed to the Asselian species do not belong to them and are their homeomorphic analogs. These conclusions required additional sub stantiation. For this purpose, we studied the section described below, which contains the Chili Formation with fusulinids. The fusulinid collection no. 4798 is stored at the Geological Institute, Russian Academy of Sciences. BRIEF DESCRIPTION OF THE SECTION The Rahdar section is located 53.6 km west of the town of Tabas at the western anticline wedge cut through by the Kalmard fault from the west (Fig. 1). The coordinates of the section are 33°35′54′′ N and 56°20′51′′ E. The Permian rocks in the reviewed sec tion overlap the pale white quartz sandstones and sandy limestones of the Padeh Formation without vis ible angular unconformity. They contain Visean–Ser pukhovian foraminifers—Pseudoammodiscus volgen sis (RauserChernousova), P. buskensis (Brazhni kova), Monotaxinoides sp., Mediocris evolutis Ros ovskaya, Endothyra bradyi Mikhailov, Endothyranopsis

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7 Sartakht

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pressus (Grozdilova), Eostaffella ex gr. pseudostruvei RauserChernousova et Beljaev, and E. parastruvei RauserChernousova (identification by E.L. Zaitseva). The Permian part of the section includes the Chili, Sartakht, Hermez, and Rizi formations distinguished in the Kalmard block. Because we are interested in fusulinids, we will describe only the first of the listed formations. No fusulinids were found in other forma tions. The Chili Formation is clearly subdivided into seven layers (from bottom to top, Figs. 2 and 3): 1. Gray mediumlayered peloid–ooid–bioclastic (in the lower part) and peloid–bioclastic (in the upper part) limestones. Bioclasts include small foraminifers, tubiphytes, crinoids, algae, and brachiopod shells. Fusulinids of the Pseudoendothyra sp. and Reitlinger ina (?) sp. are often observed (samples CKR14 and CKR15). The thickness is 16 m. 2. Pale gray almost white coarselayered to massive limestones with small coral bioherms. Under a micro scope, one can distinguish bioclastic and peloid–bio clastic (ooid–bioclastic in the upper part of the layer) grainstones and packstones. Small foraminifers (Cli

macammina), tubiphytes, needles of echinoderms, and brachiopods were observed among bioclasts. Rare fusulinids are Grovesella sp., Nonpseudofusulina ex gr. karapetovi (Leven), and Nonpseudofusulina sp. indet. (samples CKR18, CKR20, and CKR21). The thickness is 5 m. 3. Gray fine to mediumlayered limestones (grain stone and rudstone with carbonate–clayey micritic cement), locally, dolomitized, with numerous relics of crinoids, bryozoans, and brachiopods. The upper part of the layer is overcrowded with fusulinids of Non pseudofusulina pshari (Leven), N. ex gr. curteum (Leven), N. pamirensis (Leven), N. cf. aghanabatei (Davydov et Arefifard), N. karapetovi (Leven), N. ex gr. plena (Leven), Eoparafusulina regina Nie et Song, E. pamirensis Leven, E. madbeiki Davydov et Arefifard, and E. rahdarensis n. sp. (sample CKR25). The thickness is 7.5 m. Nonpseudofusulina tezakensis (Leven), N. ex gr. granuliformis (Leven), N. kalaktashensis (Leven), N. aghanabatei (Davydov et Arefifard), N. aff. memor alis (Leven), N. neglectens (Leven), and N. curteum

Fig. 3. Distribution of the fusulinids in the section of the Chili Formation. (1) dolomite; (2) bioclast limestone; (3) nodular lime stone; (4) marl; (5) sandy limestone; (6) oolitic limestone; (7) clay; (8) sandstone. STRATIGRAPHY AND GEOLOGICAL CORRELATION

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(Leven) (sample S) were found in some outcrops on the layer strike. 4. Dark gray wavy and finelayered nodular lime stones (grainstone and packstone) with relics of bryo zoans and fusulinids of the Nonpseudofusulina and Eoparafusulina genera. The latter, unfortunately, are poorly preserved, which makes difficult their more precise identification. The thickness is 4 m. 5. Gray and brownish gray fine and mediumlay ered bioclastic fusulinid limenstones (grainstone and rudstone), often oxidized, with marl interlayers. The relics of crinoids, brachiopods, and bryozoans occur along with fusulinid species of the Nonpseudofusulina genus—N. karapetovi (Leven), N. curteum (Leven), N. aff. incompta (Leven), N. cf. macilenta (Leven), and N. aff. juresanensis (RauserChernousova) (samples CKR28, CKR30–CKR35, CKR39, CKRR). Only near the top did we find the small interlayer with Grovesella tabasensis Davydov et Arefifard, Boultonia ex gr. willsi Lee, Parazellia ex gr. rahdarensis n. sp., P. elongata (Saurin), Nonpseudofusulina sp., and Eoparafusulina sp. (sample CKR40). The thickness is 8.5 m. Sample LPKR23 with Nonpseudofusulina plena (Leven), N. curva (Leven), and N. karapetovi (Leven) was taken at the northern strike of the layer. 6. Pale yellowish brown medium and coarselay ered dolomites. The thickness is 2.7 m. 7. Dark gray fine and mediumlayered limestones, locally dolomitized (grainstone, rudstone with small detrital or micritic cement) with numerous fusulinids and small foraminifers. Millerella ? sp., Grosevella tabasensis Davydov et Arefifard, Schubertella sp., Biwaella ex gr. omiensis Morikawa et Isomi, Biwaella ? sp., Benshiella khorasanensis compacta subsp. nov., Parazellia rahda rensis n. sp., P. elongata (Saurin), Nonpseudofusulina bozorgniai n. sp., N. aff. moelleri implicata (Shamov), N. ruttneri Leven, Eoparafusulina regina Nie et Song, and E. ex gr. tschernyschewi (Schellwien) were identi fied among the fusulinids (samples CKR41–CKR56). The thickness is 8.5 m. The total thickness of the Chili Formation is 52.2 m. It has a sharp contact with overlapping clays (in the basement) and sandstones of the lower part of the Sartakht Formation.

ANALYSIS OF THE FUSULINID COMPLEXES Fusulinids and small foraminifers from the layers underlying the Chili Formation allow us to date them as Visean–Serpukhovian. Small shtaffellides (Pseudoendothyra and Reitlinge rina) in layer 1 of the Chili Formation are stratigraph ically widespread from the lower parts of the Late Car boniferous up to the Permian inclusive. A more precise age of the layer could not be identified. We accept it as Permian, because Permian bryozoans and Asselian– Sakmarian conodonts (somewhat upward) were found in the Padeh section located north of the Kalmard block in limestones of the Chili Formation bottom, which are similar to limestones from the reviewed sec tion (Leven and Gorgij, 2011). Rare fusulinids occurring in layer 2 are undoubt edly Permian. The Grovesella and Nonpseudofusulina genera are stratigraphically widespread, but the N. karapetovi species is typical of the Sakmarian Kalaktash fusulinid complex (Leven and Gorgij, 2011). The Kalaktash complex (Plates I and II) is well represented in layers 3 and 4 and most of layer 5. The numerous species of the Nonpseudofusulina and, to a lesser degree, Eoparafusulina genera constitute the basis of the complex. Eoparafusulina species are mostly concentrated in layer 3 and include species known from other sections of the Kalmard block. Only the E. rahdarensis species is new. The set of species of the Nonpseudofusulina genus is nearly the same as that in other sections of the Kalmard block. The exception is a form similar to Nonpseudofusulina memoralis (Leven) from the Kalaktash section of the Central Pamir, which is distinct from typical representatives of this species only by a somewhat shorter shell. It is very close to some specimens of Pseudofusulina moelleri (Schellwien) described by RauserChernousova (1965) in the Sakmarian Stage of the South Urals. The form from the Urals differs only in sharper shell ends in the outer volutions. Another form not previously found was identified as Nonpseudofusulina ex gr. jure sanensis (RauserChernousova). It is very similar to the holotype of the mentioned species from the base ment of the Artinskian Stage in the sections of the Middle Urals (RauserChernousova, 1940), differing only by a larger size at the same amount of volutions. The fusulinid community found in the uppermost part of layer 5 (sample CKR40) strongly differs from those of the Kalaktash complex, mostly, by subspheri

Plate I. Fusulinids of the Kalaktash complex. Magnification of ×10 in all figures; the scale bar is 1 mm. (1–4) Nonpseudofusulina pamirensis (Leven), axial sections: (1) GIN 4798/1, sample S18; (2) GIN 4798/2, sample S20; (3, 4) GIN 4798/3 and GIN 4798/4, respectively, sample CKR25; (5) Nonpseudofusulina ex gr. insignis (Leven), axial section, GIN 4798/5, sample S23; (6) Nonpseudofusulina ex gr. curva (Leven), axial section, GIN 4798/6, sample LPKR; (7) Nonpseudofusulina ex gr. curteum (Leven), axial section, GIN 4798/7, sample S25; (8) Nonpseudofusulina neglectens (Leven), axial section, GIN 4798/8, sample S19. STRATIGRAPHY AND GEOLOGICAL CORRELATION

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cal Parazellia peculiar to the Halvan fusulinid com plex. As was noted, the latter was identified in the sec tions of the Halvan Mountains, where it is confined to the clasts of conglobreccia from the basement of the Sartakht Formation. Previously, its age was deter mined as Asselian (Leven and Gorgij, 2009). Later, it was changed to Sakmarian–Early Artinskian on the basis of additional samples both in the conglobreccia clasts (Leven and Gorgij, 2011) and in the upper parts of the Chili Formation in the Darin locality (Leven et al., 2011). Here, the Kalaktash fusulinid complex, in the same way as in the reviewed section, gives way to the Halvan complex in the normal bed consequence. In addition to Parazellia, sample CKR40 contains a lot of Boultonia, not yet found in the Kalaktash com plex. One can observe Nonpseudofusulina, whose spe cies cannot be identified, and rare Eoparafusulina dis tinct in exterior appearance from the representatives of these genera in the Kalaktash complex. The Halvan complex (Plates III and IV) is well pre sented in the upper layers of the section (layer 7, sam ples CKR41–CKR56). As in sample CKR40, Parazel lia species are the most noticeable. In most cases, these are spherical forms very similar to Parazellia falx (RauserChernousova) from the intermediate part of the Asselian Stage of the Urals (RauserChernousova and Shcherbovich, 1949). This similarity provided the basis to ascribe similar forms from previously described sections to this species and consider the lay ers characterized by them as Asselian (Leven and Gorgij, 2009, 2011). After the younger age of these lay ers was proved, some doubts were cast upon the refer ence of the Uralian and Iran subspherical forms to the same species. Their more careful comparison has shown that, at undoubtedly general similarity, the Iran forms are distinct in freer spiral coiling and somewhat larger sizes. This and age differences allowed consider ation that Iran forms represent an independent spe cies—Parazellia rahdarensis n. sp. Along with this species in the Rahdar section, as well as in all earlier described sections of the Kalmard block, Parazellia forms with longer shell ascribed to the P. elongata (Saurin) species occur. This species was described in the Sakmarian layers of some Vietnamese sections (Saurin, 1954). The Sakmarian Stage was considered by the author as Asselian + Sakmarian.

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Along with Parazellia, a significant role in the Hal van complex of the described section belongs to Non pseudofusulina species, which, as well as Parazellia, are close to some species described in the Asselian and Lower Sakmarian rocks of the Urals, such as N. exu berata and N. decurta (Shamov, 1940, 1958). In spite of an insignificant difference between nonpseud ofusulinids from the Rahdar section and mentioned Urals species, it is possible to separate them into the independent species of N. bozorgniai, remembering its younger age in comparison to species described by D.F. Shamov. Along with multiple representatives of this species, we found one specimen of nonpseud ofusulinds almost indistinguishable from Pseudo fusulina moelleri implicata Shamov from the Lower Sakmarian layers of the Urals (Shamov 1940) and also one specimen of N. ruttneri Leven, which was first described in the Halvan complex of the Sang–Variz section (Leven and Gorgij, 2011). Benshiella of the B. halvanesis and B. khorasanensis species identified earlier in this complex in the Tan gale–Mokhtar section plays important role among the reviewed fusulinids of the Halvan complex (Leven and Gorgij, 2009). The Rahdar representatives of the B. khorasanensis species are slightly distinct from the typical forms by a tighter spiral and consequently smaller sizes, which allowed us to separate them into the independent species B. khorasanensis compacta. The presence of rare representatives of the Grove sella, Schubertella, and Biwaella genera should be noted in the Halvan complex of the reviewed section. The first two are the transitional genera from the Kalaktash complex, whereas Biwaella occurs only in the Halvan complex in the sections of the Kalmard block. CONCLUSIONS The given material confirms previous data that the Halvan fusulinid complex is not Asselian. Its location in the section over the layers with Kalaktash fusulinids, which were previously found along with Sakmarian conodonts, unambiguously indicates that the age of this complex is not older than the Late Sakmarian, and it cannot be excluded that it is Early Artinskian. No species of the Halvan complex were found in stratotypical sections of the Uralian rocks of the corre

Plate II. Fusulinids of the Kalaktash complex. Magnification of ×10 in all figures; the scale bar is 1 mm. (1) Nonpseudofusulina ex gr. juresanensis (RauserChernousova), axial section, GIN 4798/9, sample CKRR; (2) Nonpseudofusulina aff. memoralis (Leven), subaxial section, GIN 4798/10, sample S23; (3) Nonpseudofusulina karapetovi (Leven), axial section, GIN 4798/11, sample CKR34; (4, 5) Eoparafusulina pamirensis Leven, axial sections, GIN 4798/12 and GIN 4798/13, respectively, sample CKR25; (6, 9) Nonpseudofusulina plena (Leven), axial sections, GIN 4798/14 and GIN 4798/17, respectively, sample LPKR; (7, 8) Eoparafusulina rahdarensis Leven, n. sp., axial sections: (7) GIN 4798/15, sample CKR25; (8) GIN 4798/16 (holotype), sample S25; (10) Nonpseudofusulina psharti (Leven), axial section, GIN 4798/18, sample CKR25; (11) Nonpseudofusulina kalaktashensis (Leven), axial section, GIN 4798/19, sample S21; (12) Nonpseudofusulina tezakensis (Leven), axial section, GIN 4798/20, sample S21; (13) Nonpseudofusulina aghanabatei (Davydov et Arefifard), axial section, GIN 4798/21, sample S23. STRATIGRAPHY AND GEOLOGICAL CORRELATION

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sponding age. For the majority of them, the Uralian sections contain morphologically similar forms in the Asselian Stage or lower part of the Sakmarian Stage. Thus, a striking homeomorphy of fusulinids of differ ent age is found and this should be taken into account in dating of layers characterized by them. DESCRIPTION OF NEW FUSULINE SPECIES FAMILY RUGOSOFUSULINIDAE DAVYDOV, 1980

Genus Benshiella Leven, 2009 Benshiella khorasanensis Leven, 2009

The first description of the species was given in the paper of Leven and Gorgij (2009, p. 55, Plate 2, figs. 10, 12, 15). The forms with tighter coiling were attributed to the species in comparison with other rep resentatives of the genera. All species representatives originated from the clasts in conglobreccias over lapped the Chili Formation in the section of the Hal van Mountains. Multiple fusulinids, accompanying Benshiella, resembled Asselian ones. Consequently, their age was identified. The additional sampling, however, allowed us to change the age of the Halvan fusulinid complex to the Late Sakmarian–Early Artinskian. The Halvan complex occurs in the upper parts of the Chili Formation in the Rahdar section. As in the Halvan section, it hosts a lot of Benshiella, including those similar to B. khorasanensis. All of them, how ever, are distinct in relatively tighter spiral and smaller sizes, respectively. Taking into account these constant differences, we assigned similar forms to an indepen dent subspecies. Thus, the Benshiella khorasanensis species is subdivided into B. khorasanensis khorasan ensis and B. khorasanensis compacta subspecies. The description of the latter is given below. Benshiella khorasanensis compacta Leven, subsp. nov. Plate III, figs. 9, 11, 12, 14–16 Benshiella khorasanensis Leven: Leven and Gorgij, 2011, Plate III, fig. 15.

S u b s p e c i e s n a m e from Latin “compactus,” compact.

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H o l o t y p e. GIN 4798/36, subaxial section; Iran, Rahdar section, Chili Formation. M a t e r i a l. Eight axial and subaxial sections. D e s c r i p t i o n. The shell is fusiform to short fusiform, commonly with slightly elongated round– sharp ends. The adult specimens have five to six volu tions with L = 5.5–6.3 mm, D = 1.4–2.2 mm, and L : D = 2.5–4. The spherical proloculus is 0.2– 0.32 mm in outer diameter. The coiling is tight, regu lar, with gradually increasing height of the consequent volutions. The keriothecal wall is thin (0.1 mm in the last whorl) with finely corrugated tectum. The septa are thin and folded. The folding is low and irregular. The tunnel is narrow with more or less stable volu tions. The chomata are present only in the proloculus. The wide axial fillings are well manifested in the axial part of the internal three to four volutions. C o m p a r i s o n. The described subspecies differs from Benshiella khorasanensis khorasanensis Leven, 2009 by tighter coiling and smaller sizes. L o c a l i t y a n d a g e. Iran, Kalmard block, upper part of the Chili Formation in the Rahdar and Padeh sections (Leven and Gorgij, 2011); Late Sak marian–Early Artinskian age. FAMILY SCHWAGERINIDAE DUNBAR ET HENBEST, 1930 SUBFAMILY PSEUDOSCHWAGERININAE CHANG, 1963

Genus Parazellia RauserChernousova, 1960 Parazellia rahdarensis Leven, sp. nov. Plate III, figs. 1, 3, 4 Eozellia falx (RauserChernousova): Leven and Gorgij, 2009, p. 57, Plate I, fig. 1. Parazellia falx (RauserChernousova): Leven et al., 2011, pl. 2, fig. 1. Parazellia aff. falx (RauserChernousova): Leven and Gorgij, 2011, Plate IV, figs. 1, 6.

N a m e d a f t e r the Rahdar settlement. H o l o t y p e. GIN 4798/22, axial section; Iran, Rahdar section, Chili formation. M a t e r i a l. Eight axial and 15 subaxial and oblique sections.

Plate III. Fusulinids of the Halvan complex. Magnification of ×10 in all figures; the scale bar is 1 mm. (1, 3, 4) Parazellia rahdarensis Leven, n. sp., axial and subaxial sections, GIN 4798/22 (holotype), GIN 4798/24, and GIN 4798/25, respectively, sample CKR45; (2, 5) Parazellia elongata (Saurin), subaxial sections: (2) GIN 4798/23, sample CKR53; (5) GIN 4798/26, sample CKR40; (6) Parazellia ex gr. rahdarensis Leven, n. sp., axial section, GIN 4798/27, sample CKR40; (7, 10, 13) Benshiella halvanesis Leven, axial sections, GIN 4798/28, GIN 4798/31, and GIN 4798/34, respectively, sample CKR56; (8) Nonpseudofusulina moelleri implicata (Shamov), subaxial section, GIN 4798/29, sample CKR52; (9, 11, 12, 14–16) Ben shiella khorasanensis compacta Leven n. subsp., axial and subaxial sections: (9) GIN 4798/30, sample CKR56; (11) GIN 4798/32, sample CKR51; (12) GIN 4798/33, sample CKR51; (14) GIN 4798/35, sample CKR52; (15) GIN 4798/36 (holotype), sample CKR51; (16) GIN 4798/37, sample CKR45.


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D e s c r i p t i o n. The shell is large, subspherical or rarely spherical with L = 6.0–7.7 mm, D = 5.0– 5.5 mm, L : D = 1.00–1.35. The adult specimens have five to six volutions, the first two to three of which are tightly coiled and make the wellmanifested juvenar ium. The coiling of the consequent volutions is broad and free; the height of the last volution is usually smaller than that of the previous one. The proloculus is spherical with outer diameter of 0.3–0.4 mm. The keriothecal wall is moderately wide in the internal volution and up to 0.15–0.20 mm thick in the last one to two volutions. The septa are thin with moderate and irregular folding, usually embracing only the lower septa edge. The axial reticulation are narrow and free. The tunnel is low, unstable with respect to volutions, and narrow in the juvernarium, widely extending in the subsequent volutions. The juvenarium contains clear chomata, disappearing in the later volutions. C o m p a r i s o n. The shell morphology and style of septa folding and the juvenarium of the described species are close to Parazellia falx (RauserChernous ova) from the Ural sections. It is distinct from the lat ter by greater sizes and freer and less regular coiling with sharper change in the volution height after the juvenarium. In addition, Parazellia falx is Middle Asselian, whereas the age of the layers where the described species is found is no older than Late Sak marian. L o c a l i t y a n d a g e. Iran, Kalmard block, upper part of the Chili Formation in the Rahdar and Darin sections (Leven et al., 2011) and in clasts of conglobreccias, overlapping the Chili Formation in the Tangale–Mokhtar and Sang–Variz sections (Leven and Gorgij, 2009; 2011); Late Sakmarian– Early Artinskian age. FAMILY PSEUDOFUSULINIDAE DUTKEVICH, 1934

Genus Nonpseudofusulina Leven, 2008 Nonpseudofusulina bozorgniai Leven, sp. nov. Plate IV, figs. 1–5, 8 Nonpseudofusulina ex gr. exuberata Shamov: Leven and Gorgij, 2011, Plate IV, figs. 2, 3, 12; Leven et al., 2011, pl. 2, fig. 6.

N a m e d i n h o n o r of F. Bozorgnia, who described the Paleozoic foraminifers of the Alborz. H o l o t y p e. GIN 4798/38, axial section; Iran, Rahdar section, Chili Formation. M a t e r i a l. Seven axial and ten oblique sections. D e s c r i p t i o n. The shell is medium, shortly fusiform, locally almost rhombic, with round–sharp ends. The adult specimens have 5.0–5.5 volutions with L = 5.3–7.7 mm, D = 2.2.–3.1 mm, and L : D = 2–3. The proloculus is small, spherical, with outer diameter of 0.23–0.40 mm. Spiral is evenly coiled with slow and gradually increasing height of volutions. The wall with

thin alveolar keriotheca is moderately thick up to 0.125 mm in the last volutions. The septa are thin and folded. The folding is weak, irregular, increasing from the shell center to its ends and gradually transiting into more or less complicated axial reticulation. The arches are round and mostly low. The tunnel is narrow with irregular volutions. Chomata and axial fillings are absent. C o m p a r i s o n. The described species has the greatest similarity to Pseudofusulina declinata Shamov from the Ural Sakmarian rocks but is distinct in more swollen, almost rhombic shell shape in the medium part. In this respect, the shortened representatives of the described species are close to Pseudofusulina exu berata macra Shamov and Pseudofusulina conspiqua RauserChernousova from the Late Asselian and Urals Sakmarian layers, but these species have more intense and higher septa folding. L o c a l i t y a n d a g e. Iran, Kalmard block, upper part of the Chili Formation in the Rahdar and Darin sections and also in clasts of conglobreccias overlapping the Chili Formation in the Sang–Variz section (Leven and Gorgij, 2011); Late Sakmarian– Early Artinskian age. Genus Eoparafusulina Coogan, 1960 Eoparafusulina rahdarensis Leven, n. sp. Plate II, figs. 7, 8

N a m e d after Rahdar location. H o l o t y p e. GIN 4798/16, axial section; Iran, Rahdar section, Chili Formation, sample CKR45. M a t e r i a l. Two axial and five subaxial and oblique sections. D e s c r i p t i o n. The shell is small and subcylin drical with round–sharp ends. The adult specimens have seven to eight volutions with L = 6.0–6.5 mm, D = 1.5–1.6 mm, and L : D = 3.8–4.3. The prolocu lus is very small (0.03 mm). The first volution is coiled under a large angle to the shell axis. The coiling of the subsequent volutions is very tight and regular. The keriothecal wall is thin. Its thickness in the last volu tion is 0.05 mm, occasionally 0.07 mm. The septa are thin and folded. The arches are low and round, gradu ally transiting into simple axial reticulation. The tun nel is low, moderately wide, with unstable volutions. All volutions, excluding the last one, contain small round chomata; poorly outlined axial fillings are developed along the axis. C o m p a r i s o n. The elongated shell of the described species is the most similar to that of Eoparafusulina pamirensis Leven, differing in smaller proloculus, thinner wall, and tighter coiling of the volutions, the first of which is endotyroid.


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419 Plate IV

1

2 A 3 B

4

5 7 6

8

10

9

C

11

12

13 D

15 14

16

19

18

17

20

21

Plate IV. Fusulinids of the Halvan complex. figs. 1–5, 8, 10, 14, 16–21—magnification of ×10 (scale bar A is 1 mm); figs. 6, 7—mag nification of ×70 (scale bar B is 0.3 mm); figs. 9, 13, 15—magnification of ×40 (scale bar C is 0.5 mm); Figs. 11, 12—magnification of ×50 (scale bar D is 0.5 mm). (1–5, 8) Nonpseudofusulina bozorgniai Leven, n. sp., axial sections: GIN 4798/38 (holotype), sample CKR49; (2) GIN 4798/39, sample CKR52; (3) GIN 4798/40, sample CKR56; (4) GIN 4798/41, sample CKR53; (5) GIN 4798/42, sample CKR51; (8) GIN 4798/44, sample CKR45; (6, 7) Grovesella tabasensis Davydov et Arefifard, axial sections: (6) GIN 4798/43, sample CKR55; (7) GIN 4798/27, sample CKR40; (9) Schubertella sp. axial section, GIN 4798/45, sample CKR45; (10) Nonpseud ofusulina ruttneri Leven, axial section, GIN 4798/46, sample CKR52; (11, 12) Boultonia ex. gr. willsi Lee, axial sections: (11) GIN 4798/26, sample CKR40; (12) GIN 4798/47, sample CKR40; (13, 15) Biwaella ex. gr. omiensis Morikawa, subaxial sections: (13) GIN 4798/48, sample CKR49; (15) GIN 4798/25, sample CKR45; (14) Eoparafusulina sp., axial section, GIN 4798/49, sample CKR53; (16, 18–21) Eoparafusulina ex gr. tschernyschewi (Schellwien), axial and subaxial sections: (16) GIN 4798/50, sample CKR54; (18) GIN 4798/52, sample CKR52; (19) GIN 4798/53, sample CKR45; (20) GIN 4798/54, sample CKR53; (21) GIN 4798/55, sample CKR45; (17) Eoparafusulina regina Nie et Song, subaxial section, GIN 4798/51, sample CKR56. STRATIGRAPHY AND GEOLOGICAL CORRELATION

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L o c a l i t y a n d a g e. Iran, Kalmard block, Chili Formation in the Rahdar section; Sakmarian age. ACKNOWLEDGMENTS We are sincerely grateful to E.L. Zaitseva for the determination of the Lower Carboniferous forami nifers. Reviewer A.S. Alekseev REFERENCES Davydov, V.I. and Arefifard, S., Permian fusulinid fauna of periGondwanan affinity from the Kalmard Region, East Central Iran and its significance for tectonics and paleo geography, Palaeontol. Electronica, 2007, vol. 10, Iss. 2. Leven, E.Ja. and Gorgij, M.N., Fusulinids of the Khan For mation (Kalmard region, Eastern Iran) and some problems of their paleobiogeography, Rus. J. Earth Sci., 2007, vol. 9, p. ES1004, doi: 10.2205/2007ES000219 Leven, E.Ja. and Gorgij, M.N., Section of Permian deposits and fusulinids in the Halvan Mountains, Yazd Province, Central Iran, Stratigr. Geol. Correlation, 2009, vol. 17, no. 2, pp. 155–172. Leven, E.Ja. and Gorgij, M.N., The Kalaktash and Halvan assemblages of Permian fusulinids from the Padeh and SangVariz sections (Halvan Mountains, Yazd Province, Central Iran), Stratigr. Geol. Correlation, 2011, vol. 19, no. 2, pp. 141–159.

Leven, E.Ja., Naugolnykh, S.V., and Gorgij, M.N., New findings of Permian marine and terrestrial fossils in Central Iran (the Kalmard block) and their significance for correla tion of the Tethyan, Uralian, and West European Scales, Riv. Ital. Paleontol. Stratigr., 2011, vol. 117, no. 3, pp. 355– 374. RauzerChernousova, D.M., Foraminiferal Stratigraphy of Upper Carbonaceous and Artian Stage of the western slope of the Urals, Tr. Inst. Geol. Nauk AN SSSR. Geol. Ser., 1940., no. 2, pp. 37–101. RauzerChernousova, D.M. and Shcherbovich, S.F., Schwagerins of the European part of the USSR, Tr. GIN AN SSSR. Geol. Ser. 1949., no. 105, pp. 61–117. RauzerChernousova, D.M., Foraminifery stratotip icheskogo razreza sakmarskogo yarusa (r. Sakmara, Yuzhnyi Ural) (Foraminifers in the Stratotypical Section of the Sak marian Stage (Sakmara River, Southern Ural)), Moscow: Nauka, 1965 [in Russian]. Saurin, E., Notes paleontologiques sur quelques calcaires a fusulinides du Nord VietNam. II. Nouvelles observations sur les calcaires de Ku Lua, Archives Geologiques du Viet Nam, 1954, no. 1, pp. 3–21. Shamov D.F. On geological structure of Ishimbai oilbear ing region, Sov. Geol., 1940, no. 11, pp. 6–20 [in Russian]. Shamov, D.F., Inflatedfusiform group of pseudofusulins from Schwagerinahorizon of Ishimbai–Sterlitamak oil bearing region, Tr. GIN AN SSSR, 1958, no. 13, pp. 139– 154 [in Russian].

Translated by I. Melekestseva


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