Scientific Quarterly Journal of Geosciences

Scientific Quarterly Journal of Geosciences

Biostratigraphy of Oligocene and Lower Miocene Sediments (Pabdeh, Asmari, Gachsaran and Mishan Formations) on the basis of Foraminifera in Southwest Jahrum, Interior Fars

Document Type : Original Research Paper

Authors
J. Daneshian 1
D, Baghbani 2
S.A. Aghanabati 3
N. Norouzi 4
1 Department of Geology, Tarbiat Moallem University, Tehran, Iran
2 Surface Geology, NIOC Exploration Directorate, Geology Department, Tehran, Iran
3 Geological Survey of Iran, Tehran, Iran
4 Islamic Azad University, Science and Research Branch, Tehran, Iran
10.22071/gsj.2012.54538
Abstract
Oligocene-Lower Miocene sediments at Nareh section, situated in SW Jahrum consists of limestone, argillaceous limestone, marl and evaporatic sediments with a rich association of planktonic and benthonic foraminifera. In lower part of this succession, the Pabdeh sediments with a thickness of 115m is composed of shale, marl and intercalations of argillaceous limestone. The mentioned sediments continue through Late Eocene to Oligocene, which are overlain conformably by the Asmari Formation. The Asmari Formation consists of 250 m limestone and argillaceous limestone of which 210 m belongs to the lower Asmari and 40 m to middle Asmari. Argillaceous limestone and evaporatic-marly sediments of the Gachsaran Formation are overlain by the Asmari Formation. The Gachsaran Formation with a thickness of 510m is composed of three members of Chehel, Champeh and Moll. Pure and thick basal limestones of the Mishan Formation (Guri Member) with a thickness of 302 m, is situated above the Gachsaran Formation. Finally, Bakhtyari conglomerate lies uncomformably over the Mishan Formation. Variety of studied rock units in this section has caused different sedimentary environments, different facies and presence of abundant planktonic and benthonic foraminifera. By studying 203 samples including 193 hard and 10 washed samples, 34 genera and 47 species of benthonic foraminifera and 8 genera and 13 species of planktonic foraminifera, algae, briozoa and different macrofossils fragments were identified. Based on  foraminiferal assemblages, the age of the lower part of the Pabdeh Formation is Late Eocene (Priabonian) and the upper part is Early Oligocene and the Asmari Formation is Oligocene (Late Rupelian-Chattian) to Early Miocene (Aquitanian). Also, the Gachsaran Formation belongs to Early Miocene (Aquitanian-Burdigalian) and the age of the Mishan Formation (Guri Member) is Late Miocene (Burdigalian) .On the basis of recognized foraminifera association, Nareh stratigraphical section can be correlated with first to fourth Biozones of biozonation of Adams and Bourgeois (1967) and 54,57,59,61,63 and 64 Biozones of Wynd (1965).
Keywords
Foraminifera
Biostratigraphy
Oligocene-Lower Miocene
Interior Fars
References
Adams, T. D., 1969-The Asmari Formation of Lurestan and Khuzestan proviences.IOOC  Report,  No.1154(Unpub).
Adams, T. D. and Bourgeois, F., 1967- Asmari biostratigraphy, Geological and Exploration Division, IOOC Report, No.1074, (Unpubl).
Blow, W. H., 1969- Late Middle Eocene to Recent planktonic foraminiferal biostratigraphy. Proc. Intern. Conf. Planktonic Microfossils, 1st,1: 199-421.
Busk, H. G. and Mayo, H. T., 1918- Some notes on the geology of the Persian Oilfield, Journal Institut Petroleum Tecnology 5, 5-26.         
Clapp, F.G., 1940- Geology of eastern Iran:Geol.Soc.Amer.Bull.,vol.51.no.1,pp.1-101.
Ehrenberg, S. N., Pickard, N. A. H., Laursen, G. V., Monibi, S., Mossadegh, Z. K., Svana, T. A., Aqrawi, A. A. M., Mc Arthur, J. M., Thirlwall, M., 2007- Strontium isotope stratigraphy of the Asmari Formation (Oligocene-Miocene),SW Iran. Journal of Petroleum Geology, 30(2), 107-128.
Furon, R., 1941-Geologie de plateau Iranian (Perse-Afghanistan-Beloutchistan): Mem.Mus.Nath.Hist,Nat.Pars.vol.7,pt.2,pp.177-411.   
Hamedani, A., Torabi, H., Piller, W., Mandic, O., Steininger, F.F., Wielandt, U., Harzhauser, M. Nebelshck, L.H., Schuster, F., 1997- Oligocene/Miocene section from Zagros forland basin of central Iran. –Abstr., 18 th. IAS Regional Meeting of Sedimentol., 155-156, Heidelberg.             
Jalali, M. R., 1987- Stratigraphy of Zagros Basin. National Iranian Oil Company, Expl. and Prod. Div. Report, no.1249 and 1072.
James, G. A. and Wynd, J. G., 1965- Stratigraphic nomenclature of Iranian Oil Consortium Agreement area, AAPG Bulletin 49, 2182-2245.
Kalantari, A., 1981- Iranian fossil, National Iranian Oil Company, Lab., Public., no.9.
Kheradpir, A.,Brookly, A.C.and 1962- Paleontological Appendix report for sub-Coastal and interior fars Geological survey,1962-63.IOOC Report. No. 1045A (Unpub).
Khosravi Said, A., 1962- Map No.20515-52, interior Fars Geological Survey,   IOOC, Geological and Expoloration Div.
Laursen,G.V., Allen,T.L. Tahmasbi, A.R., Karimi, Z., Monibi, A., Vincent, B., Moallemi, A. M. and van Buchem, F., 2006- Reassessment of the age of the Asmari formation,   Iran. Abstract, foruma 2006,10-15 septamber 2006,Natal,Brazil.  
Lees, G. M., 1933-Reservoir rocks of Persian oil field:Am. Assoc. Petrol. Geol. B.,V.17, No.3,p.229- 240
Pilgrim,G. E., 1908-The geology of the Persian Gulf and the adjoining portion of   Persia and Arabia:Mem.Geol.Survey of India memoir, vol.24,pt.4,pp.1-177.
Postuma, J. A., 1971- Manual of Planktonic Foraminifera,Elsevire Publishing Company, Amesterdam. 420 p.
Racey, A., 1994- Biostratigraphy and palaeobiogeographic significance of Tartiary Nummulitids(foraminifera) from northern Oman. In:M.D. Simmons (ed.) Micropalaeontology and Hydrocarbon  Exploration in the Middle East. Chapman & Hall, London. ISBNO  412427702.
Reichel, M., 1937- Observation sur le genre Loftusia:Verh.Schweiz.naturf. Ges.,v.118, pp.142-143.
Richardson, R. K., 1924- The geology and oil measures of southwest Persia:Journal Institute Petroleom Technology ,V.10,No.43,p.256-296.
Setudehnia, A., 1972- Iran du sud-ouest;Lexique stratigraphique international, III(2)   CNRS, Paris.
Seyrafian, A., 1981- Geological study of Siah Makan Field (Asmari Formation). National Oil Company, Rep., P.3745,(unpubl.).
Seyrafian, A. and Hamedani, A., 1998- Microfacies and depositional environment of the upper Asmari Formation (Burdigalian), North- Central Zagros Basin, Iran. Neues   Jahrbuch fur   Geologie und Paleontologie Abhandlungen, 210(2), 129-414.
Seyrafian, A., Vaziri, H. and Torabi, H., 1996- Biostratigraphy of the Asmari Formation, Burujen area: J. Sci., I. R. Iran, v.7, no.1. p.31-47, Tehran.
Strong, M. W., 1937- Micropetrographic methods as an aid to the stratigraphy of chemical deposits: World Petrol congr.2 nd., Paris, vol.1, pp.395-399.
Thomas, A. N., 1948- The Asmari Limestone of southwest Iran, ALOC Report 706, Unpublished.
Watson, S. E., 1960 a- Revision of the lower Fars key beds in the Gachsaran field.  IOOC Report No.946 (Unpub).
Wells, A. J., 1967- Lithofacies and geological history of lower Tertiary sediments in Southwest Iran, IOOC Report No.1120 (Unpub).     
Wynd, J. G., 1965- Biofacies of Iranian Oil Consortium Agreement Area,Iranian Oil  Company. Report no.1082, Unpublished.
 
Scientific Quarterly Journal of Geosciences
Volume 21, Issue 83
Autumn 2012
Pages 157-166