Document Type: Original Article

Authors

1 Paleontology and Stratigraphy cultural heritage and handy craft organization and department of Geology, Payam-e- Noor University، Fars, Shiraz, Iran

2 Sedimentology and Sedimentary Petrology, Absakht hashemi Company, Fars, Shiraz, Iran

Abstract

Objective: The Asmari Formation is characterised by alternation thick carbonate and marl sequence of the Oligocene- Miocene in the Zagros Basin, southwest of Iran that were deposited on the shelf of Eastern Paratethys. Methods: This formation is exposed at Tang-e-Khoshk in the Fars subcoastal zone with a thickness of 286 m comprising alternation of medium and thick to massive bedded carbonates, marlylimestone and marl. The age of the Asmari Formation in the study area is the Oligocene (Ruplian&Chattian). Results: Ten microfacies are defined, characterizing a gradual shallowing upward trend; the related environments are as follows: open marine (MF1, 2&3), shoal (MF4) and lagoon (MF5, 6&7). A carbonate ramp platform is suggested for the depositional environment of the Asmari Formation. MF 1, 2, 3 &4 are characterized by the occurrence of large and small foraminifera representing a represent a deeper fair weather wave base of a middle ramp setting. MF 5, 6& 7 with large particles of different bioclast debis and algae, shallow-water setting of an inner ramp.

Keywords

Adams, C.G., Bourgeois, E., (1967). Asmari biostratigraphy, Geological and Exploration Iranian Oil Offshore Company Report. 1074, Unpublished.
Alavi, M., (2007). Structures of the Zagros Fold-Thrust Belt in Iran. American Journal of Science 307, 1064–1095.
Alavi, M., (2004). Regional stratigraphy of the Zagros fold-thrust belt of Iran and its proforeland evolution, American Journal of Science. 304, 1–20.
Amirshahkarami, M., Vaziri-Moghaddam, H., Taheri, A.,)2007a(. Sedimentary facies and sequence stratigraphy of the Asmari Formation at Chaman-Bolbol, Zagros Basin, Iran. Journal of Asian Earth Sciences 29, 947-959. Amirshahkarami, M., Vaziri-Moghaddam, H., Taheri, A.,)2007b(. Paleoenvironmental model and sequence stratigraphy of the Asmari Formation in southwest Iran, Historical Biology, 19(2), 173-183.
Barattolo, F., Bassi, D., Romero, R., (2007). Upper Eocene larger foraminiferal-coralline algal facies from the Klokova Mountain (south continental Greece), Facies, 53(3), 361-375.
Bassi, D., Hottinger, L., Nebelsick, H., (2007). Larger Foraminifera from the Upper Oligocene of the Venetian area, northeast Italy, Palaeontology, 5(4), 845-868.
Beavington-Penney, S.J., Racey, A., (2004). Ecology of extant nummulitids and other larger benthic foraminifera. Applications in Paleoenvironmental
analysis, Earth Science Review, 67(3-4), 219-265.
Berberian, M., King, G.C.P., (1981). Toward a paleogeography and tectonic evo-lution of Iran. Canadian Journal Earth Sciences 18, 210–265.
Burchette TP, Wright VP (1992). Carbonate ramp depositional systems. Sediment Geol 79:3–57.
Corda, L., Brandano, M., (2003). Aphotic zone carbonate production on a Miocene ramp, Central Apennines, Italy, Sedimentary Geology, 161(1-2), 55–70.
Cosovic V., Drobne K., Moro A., (2004). Paleoenvironmental model for Eocene foraminiferal limestones of the Adriatic carbonate platform (Istrian Peninsula). Facies 50:61–75.
Dunham, R.J., (1962). Classification of carbonate rocks according to their depositional texture, In: Ham, W.E. (Ed.), ClassiWcation of Carbonate Rocks. A Symposium: AAPG Bulletin, pp. 108–121.
Ehrenberg, S.N., Pickard, N.A.H., Laursen, G.V., Monibi, S., Mossadegh, Z.K., Svana, T.A., Aqrawi A.A.M., McArthur J.M., Thirlwall M.F., (2007). Strontium isotope stratigraphy of the Asmari Formation (Oligocene-Lower
Miocene), SW Iran, Journal of Petroleum Geology 30, 107-128.
Embry,AF., Klovan, JE., (1971). A Late Devonian reef tract on Northeastern Banks Island NWT: Can Petroleum Geolgy Bull. 19:730–781[revision of Dunham classification].
Flugel, E., (2010). Microfacies of Carbonate Rocks: Analysis Interpretation and Application, Springer, Berlin, p. 976.
Geel, T., (2000). Recognition of Stratigraphic sequence in carbonate platform and slope deposits: empirical models based on microfacies analyses of palaeogene deposits in southeastern Spain, Palaeogeography, Palaeoclimatology, Palaeoecology155, 211-238.
Hakimzadeh, S., Seyrafian, A., ( 2008). Late OligoceneEarly Miocene benthic foraminifera and biostratigraphy of the Asmari Formation, south Yasuj, north-central Zagros basin, Iran, Carbonates and Evaporites 23 (1), 1-10.
Hallock, P., Glenn, E.C., (1986). Larger foraminifera: a tool for paleoenvironmental analysis of Cenozoic depositional facies, Palaios, 1(1), 55–64.
Hamedani, A., Torabi, H., Piller, W., Mandic, O., Steininger, F. F., Wielandt, U., Harzhauser, M., Nebelsick, J. H., Schuster, F.,( 1997). Oligocene/ Miocene sections from Zagros foreland basins of Central Iran, Abstract, 18th IAS
Regional Meeting of Sedimentology, Heidelberg, pp. 155–156.
Heydari, E., (2008). Tectonics versus eustatic control on supersequences of the Zagros Mountains of Iran",. Tectonophysics 451, 56-70.
Jalali, M.R., (1987). Stratigraphy of Zagros Basin, National Iranian Oil Company. Exploration and Production Division Report 1249, 1072.
James G, Ogg Smith AG and Gradstin FM (2008).
Geological time scale2004.Paleozoic Time Scale and SeaLevel History and The Concise Geologic Time Scale, Purdue University, and The Concise Geologic Time Scale.
James, G.A., Wynd, J.G., (1965). Stratigraphic nomenclature of Iranian oil consortium agreement area, AAPG Bulletin 49, 2182e2245.
James, G.A., Wynd, J.G., (1965). Stratigraphic nomenclature of Iranian oil consortium agreement area, AAPG Bulletin 49, 2182e2245.
Kalantari, A., (1986). Microfacies of carbonate rocks of Iran, National Iranian Oil Company,Geological Laboratory Publication, Tehran, vol. 11, 520 pp.
Laursen, G.V., Monibi, S., Allan, T.L., Pickard, N.A., Hosseiney, A., Vincent, B., Hamon, Y., Van-Buchem, F.S.P., Moallemi, A., Druillion, G., (2009). The Asmari Formation revisited: changed stratigraphic allocation and new biozonation, First International Petroleum Conference & Exhibition. European Association of Geoscientists and Engineers, Shiraz, Iran.

Maghsoodi, M., (2002). rings of zagros structures:National Iranian oil Company (Exploration directorate).
McQuillan,H., Roohi, M. and Evers , H.J., (1978). Gological map of Ardakan (1/100000)" National Iranian oil company oil (Exploration division), sheet no. 20842E,.
Mossadegh, Z.K., Haig, D.W., Allan, T., Adabi, M.H., Sadeghi, A.,)2009(. Salinity changes during Late Oligocene to Early Miocene Asmari Formation
deposition, Zagros Mountains, Iran. Palaeogeography Palaeoclimatology Palaeoecology 272, 17-36.
Motiei, H., (1993). Stratigraphy of Zagros. In: Treatisie of Geology of Iran", Iran Geology Survey, Published, pp. 281–289.
Motiei, H., (2001). Simplified table of rock units in southwest Iran, Tehran, Keyhan Exploration and Production Services.
Nadjafi, M., Mahboubi, A., Moussavi-Harami, R., Mirzaee R., (2004). Depositional history and sequence stratigraphy of outcropping Tertiary carbonates in the Jahrum and Asmari Formations, Shiraz area (SW Iran).
Journal of Petroleum Geology 27,179–190. Nebelsick, J.H., Stingl, V., Rasser, M., (2001).
Autochthonous facies and allochthonous debris flows compared: Early Oligocene carbonate facies patterns of the Lower Inn Valley (Tyrol, Austria)". Facies 44:31–45.
Pomar, L., M. Brandano, & H. Westphal, (2004). Environment factors influencing skeletal grain sediment associations: a critical review of Miocene examples from the western Mediterranean: Sedimentology, v. 51, p. 627-651.
Rahmania, A., Vaziri-Moghaddama, H., Taherib, A. and Ghabeishavi, A. (2009). A model for the paleoenvironmental distribution of larger foraminifera of Oligocene–Miocene carbonate rocks at Khaviz Anticline, Zagros Basin, SW Iran. Historical Biology, Vol. 21, Nos. 3–4,215-227.
Rasser MW, Scheibner C, Mutti M (2005). A paleoenvironmental standard section for Early Ilerdian tropical carbonate factories (Corbieres, France; Pyrenees, Spain). Facies 51:217–232.
Rasser, M.W., Nebelsick, J.H., (2003). Provenance analysis of Oligocene autochthonous and allochthonous coralline algae: a quantitative approach towards reconstructing transported assemblages, Palaeogeography,
Palaeoclimatology Palaeoecology, 201(1), 89-111.
Romero, J., Caus, E., Rosell, J., ( 2002). A model for the palaeoenvironmental distribution of larger foraminifera based on late Middle Eocene deposits on the margin of the South Pyrenean basin (NE Spain). Palaeogeography,
Palaeoclimatology, Palaeoecology, 179(1), 43–56.
Sadeghi, R., H. Vaziri-Moghaddam, and A. Taheri, (2010). Microfacies and sedimentary environment of the Oligocene sequence (Asmari Formation) in Fars subbasin, Zagros Mountains, southwest Iran: Facies, v. 57, no. 3, p. 431-446.
Sadeghi, R., Vaziri-Moghaddam, H., Taheri, A., (2009). Biostratigraphy and Palaeoecology of the Oligo-Miocene succession in Fars and Khuzestan areas (Zagros Basin, SW Iran). Hist Biol. 21:17–31.
Sahraeyan, M., Bahrami, M., Arzaghi, S., (2013). Facies analysis and depositional environments of the OligoceneeMiocene Asmari Formation, Zagros Basin, Iran, southwestern Iran. Journal of Geoscience Frontiers,
1-10.
Seyrafian, A., Hamedani, A., (1998). Microfacies and depositional environment of the Upper Asmari Formation (Burdigalian), north-central Zagros Basin,
Iran. N. Jb. Geol. Palaont. Abh. 210/2, 129–141.

Seyrafian, A., Hamedani, A.,( 2003). Microfacies and palaeoenvironmental interpretation of the lower Asmari Formation (Oligocene), North- Central Zagros Basin, Iran. N. Jb. Geol. Palaont. Mh. 3, 164–174.
Seyrafian, A., Mojikhalifeh, A.R., (2005). Biostratigraphy of the Late Paleogene-Early Neogene succession, northcentral border of Persian Gulf, Carbonates and Evaporites, 20(1), 91-97.
Seyrafian, A., Vaziri-Moghaddam, H., Torabi, H., ( 1996). Biostratigraphy of the Asmari Formation, Burujen area, Iran. J. Sci. 7/1, 31–47.
Seyrafian, A.,(1981). Geological study of the Siah Makan Field (Asmari Formation). National Iranian Oil Company, Report, 37–45, unpublished.

Seyrafian, A.,(2000). Microfacies and depositional environments of the Asmari Formation, at Dehdes area (A correlation across Central Zagros Basin). Carbonates and Evaporites 15, 22–48.
Vaziri-Moghaddam, H., Kimiagari, M., Taheri, A.,) 2006(. Depositional environment and sequence stratigraphy of the Oligo-Miocene Asmari Formation in SW Iran. Facies, 52(1), 41-51.
Vaziri-Moghaddam, H., Seyrafian, A., Taheri, A., Motiei, H., (2010). Oligocene-Miocene ramp system(Asmari Formation) in the NW of the Zagros basin, Iran: Microfacies, paleoenvironment and depositional sequence, de Ciencias Geologicas, 27: 56-71.
Wells, A.J.,(1967). Lithofacies and geological History of Lower Tertiary sediments in southwest Iran. IOOC Report 1108.
Wilson, J.L.,)1975). Carbonate facies in geological history New York, Springer, 471 pp.
Wynd, J., (1965). Biofacies of Iranian Oil Consortium Agreement Area. IOOC Report 1082, Unpublished.
Ziegler, M. A. (2001). Late Permian to Holocene paleofacies evolution of the Arabian Plate and its hydrocarbon occurrences: Geo Arabia, 3, p. 445-504.