Ammonite and Nannofossil Biozonation of the Aitamir Formation in Eastern Kopet-Dagh Basin (Amirabad section)

Document Type : مقالات پژوهشی

Authors

• Nasim Mousavi ¹
• Anoushirvan Lotfali Kani ¹
• Abdolmajid Mosavinia ²

¹ Shahid Beheshti University

² Payam Noor University

10.22067/sed.facies.v12i2.55217

Abstract

Introduction
The Kopet-Dagh Basin is located in the northeast of Iran, extended over Iran, Turkmenistan, and Afghanistan with a west-northwest to east-southeast trend. The Iranian part of the basin is located between 61°14ˊ and 54°00ˊE and 38°16ˊ and 36°00ˊ N. Cretaceous successions are thick and well exposed in the northeast of Iran. The Cretaceous Ammonites are studied by Seyed-Emami (1980), Seyed-Emami & Aryai (1981), Seyed-Emami et al. (1984), Immel et al. (1997), Raisossadat (2004, 2006), Mosavinia et al. (2007, 2014), and Mosavinia & Wilmsen (2011). Calcareous nannoplankton biostratigraphy of Aitamir formation is studied by Susani (2005) and Hadavi & Musazadeh (2005).
Materials and Methods
The studied section, the Amirabad section, is located at a distance of 65 km to the northeast of Mashhad city, on the Mashhad-Kalat road (coordinates: N36°34ˊ59˝ and E60°09ˊ24˝; altitude: 720 m). Aitamir Formation is measured 668 m in this section and comprised siltstones, fossiliferous (bivalve and ammonite) sandstones, glauconitic sandstones, dark gray to greenish-gray silty shales, and dark gray shales. It conformably overlies the Sanganeh Formation and is overlain by the Abderaz Formation. A total of 139 samples were collected from the section at intervals 3-5 m to study the calcareous nannofossils. In addition, 40 m part of the topmost of the underlying Sanganeh Formation as well as the lowermost of the overlying Abderaz Formation were also measured and sampled. For nannofossil biostratigraphic investigations, all samples were processed using the gravity settling technique (Bown & Young, 1998). The prepared slides were observed under a Nikon Optiphot II Pol light microscope with a magnification ×1000. Bibliographic references for the calcareous nannofossils are given in Perch-Nielsen (1985), Varol (1992), and Burnett (1998). Ammonite samples were collected across the section and named and photographed at the paleontology laboratory of the Payam-e-Noor University of Mashhad.
 Discussion and Conclusion
Nannofossil bioevents have been utilized to biostratigraphically classify the exposed sedimentary succession based on the CC biozonation scheme of Sissingh (1977, modified by Perch-Nielsen, 1985) and the NC biozonation scheme of Roth (1978, modified by Bralower et al., 1995). The biozones CC8 to CC10 and NC9 to NC13 were determined, and accordingly, the Aitamir Formation is attributed to Albian to late Cenomanian time interval. The lithology of sandstones and siltstones at the lower part of the Aitamir Formation influenced the preservation of nannofossil taxa. In this part, the Ammonite biozones have covered the gap of nannofossil biozones. The upper part of Leymeriella tardefurcata, Hoplites dentatus, Euhoplites loricatus, Euhoplites lautus Mortoniceras (M.) inflatum, Stoliczkaia dispar, Mantelliceras mantelli, Mantelliceras dixoni, Cunningtoniceras inerme and Acanthoceras rhotomagense biozones were determined at the Aitamir Formation except for the upper 20 meters, which contains no ammonite sample. Based on Ammonite biozones, the age of Late Early Albian to Middle Cenomanian is attributed to the Aitamir Formation.
References
Bown, P.R., & Young, J.R., 1998. Techniques. In: Bown, P.R., (ed.), Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publications Series, Chapman and Hall/Kluwer Academic Publishers, 16-28.
Burnett, J.A., 1998. Upper Cretaceous. In: Bown, P.R., (ed.), Calcareous nannofossil biostratigraphy. British Micropalaeontological Society Publications Series, Chapman and Hall/Kluwer Academic Publishers, 132-199.
Hadavi, F., & Musazadeh, H., 2005. Characters of stratigraphic system of the Aitamir formation based on Calacareous nannofossils in Shurab section- Kopetdagh region. 24^th Symposium of Geosciences, Geological Survey of Iran, Tehran, Iran.
Immel, H., Seyed-Emami, K., & Afshar-Harb, A., 1997. Kreide-Ammoniten aus dem iranischen teil des Koppeh-Dagh (NE-Iran). Zitteliana, 21: 159-190.
Mosavinia, A., & Wilmsen, M., 2011. Cenomanian Acanthoceratoidea (CretaceousAmmonoidea) from the Aitamir Formation (Koppeh Dagh, NE Iran): taxonomyand stratigraphic implications. Acta Geologica Polonica, 61: 175-192.
Mosavinia, A., Lehmann, J., & Wilmsen, M., 2014. Late Albian ammonites from the Aitamir Formation (Koppeh Dagh, NE Iran). Cretaceous Research, 50: 72-88.
Mosavinia, A., Wilmsen, M., Aryai, A., Shahida, M., & Lehmann, J., 2007. Mortoniceratinae (Ammonitina) from the Upper Albian (cretaceous) of the Atamir Formation, Koppeh Dagh Mountains, NE Iran. Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen, 246 (1): 83-95.
Perch-Nielsen, K., 1985. Mesozoic Calcareous Nannofossils. In: Bolli, H.M., Saunders, J.B., & Perch- Nielsen, K., (eds.), Plankton Stratigraphy. Cambridge University Press, Cambridge, 329-426.
Raisossadat, S.N., 2004. The ammonite family Deshayesitidae in the Kopet Dagh Basin, north-east Iran. Cretaceous Research, 25: 115-136.
Raisossadat, S.N., 2006. The ammonite family Parahoplitidae in the Sanganeh Formation of the Kopet Dagh Basin, north-eastern Iran.Cretaceous Research, 27: 907-922.
Roth, P.H., 1978. Cretaceous nannoplankton biostratigraphy and oceanography of the northwestern Atlantic Ocean. In: Benson, W.E., & Sheridan, R.E., (eds.), Initial Reports of the Deep Sea Drilling Project 44. U.S. Government Printing Office, Washington, 731-760.
Seyed-Emami, K., & Aryai, A.A., 1981. Ammoniten aus dem unteren Cenoman von Nordostiran (Koppeh Dagh). Mitteilungen der Bayerischen Staatssammlung für Paläontologie und Historische Geologie, 21: 23-39.
Seyed-Emami, K., 1980. Parahoplitidae (Ammonoidea) aus dem Nordost und Zentral Iran. Neues Jahrbuch für Geologie und Paläeontologie, Monatshefte 1980, 719-737.
Seyed-Emami, K., Forster, R., & Mojtahedi, A., 1984. Ammoniten aus dem mittleren Cenoman von Nordost-Iran (Koppeh-Dagh). Neues Jahrbuch für Geologie und Paläontologie Monatshefte, 159-172.
Sissingh, W., 1977. Biostratigraphy of Cretaceous calcareous nannoplankton. Geologie en Mijnbouw, 56: 37-65.
Susani, A., 2005. Biostratigraphy of lower part of Aitamir Formation based on calcareous nannofossils in Shurab section. M.Sc. thesis, Ferdowsi University of Mashhad.
Varol, O., 1992. Taxonomic revision of the Polycyclolithaceae and its contribution to Cretaceous biostratigraphy. Newsletters on Stratigraphy, 27: 93-127.

Keywords

• Negor
• The whale
• fossil
• Sedimentology
• Index fossil

Main Subjects

• Systematic Paleontology & Biostratigraphy

---

References

افشارحرب، ع.، ١٣٧٣. زمین شناسی ایران، زمین شناسی کپه‌داغ. سازمان زمین شناسی و اکتشافات معدنی کشور، 275ص.

بهروزی، م.، 1392. نانوفسیل‌‎های آهکی واحد شیلی سازند آیتامیر در شمال‎ غرب کپه‎‌داغ (برش‎چرلی). پایان نامه کارشناسی ارشد، دانشگاه بیرجند.

سوسنی، ا.، 1384. بایواستراتیگرافی بخش زیرین سازند آیتامیر بر مبنای نانوپلانکتون‌های آهکی در برش شوراب (جاده مشهد ـ سرخس). پایان نامه کارشناسی ارشد، دانشگاه فردوسی مشهد.

گرمابی، ب.، موسوی ‌نیا، ع.، 1393. آمونیت‌های سنومانین در برش تقی ‌آباد (شرق حوضه کپه‌داغ). نشریه دیرینه شناسی، (2): 230ـ243.

هادوی، ف.، موسی زاده، ه.، 1384. ویژگی‌های سیستم چینه‌ای سازند آیتامیر بر مبنای نانوپلانکتون‌های آهکی در برش شروع آب (رشته کوه کپه‌داغ). بیست و چهارمین گردهمایی علوم زمین، تهران.

مافی، آ.، رئیس السادات، س.ن.، موسوی نیا، ع.، محبوبی، ا.، 1390. پالئوبیوژئوگرافی سازند آیتامیر بر اساس آمونیت‌ها، حوضه کپه‌داغ در شمال مشهد (برش بابافرجی). پنجمین همایش انجمن دیرینه شناسی ایران، مرکز بین‌المللی علوم و تکنولوژی پیشرفته در علوم محیطی، کرمان، صص 128ـ134.

معتمدالشریعتی، م.، صادقی، ع.، وزیری مقدم، ح.، موسوی حرمی، ر.، 1391. ریززیست ‌چینه نگاری سازند آیتامیر در شمال باختر حوضه کپه‌داغ (برش مراوه تپه). نشریه علوم زمین، 85: 225ـ236.

موسوی نیا، ع.، 1387. چینه ‌شناسی و فسیل ‌شناسی ردیف‌های رسوبی کرتاسه میانی در خاور کپه‌داغ (با توجه ویژه به فون آمونیتی). رساله دکتری، دانشگاه شهید بهشتی، 350ص.

Amedro, F., 1992. L' Albien du bass in Anglo-Parisien: Ammonites zonation phyletiques, sequences. Bulletindu Centres Recherche Exploration-Production EI fAqu1taine, 16 (I): 187-233.

Berberian, M., & King, G.C.P., 1981. Towards a Paleogeography and tectonic evolution of Iran. Canadian Journal of Earth Science, 18: 210-265.

Bown, P.R., & Young, J.R., 1998. Techniques. In: Bown, P.R., (ed.), Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publications Series, Chapman and Hall/Kluwer Academic Publishers, 16-28.

Bown, P.R., (ed.), 1998. Calcareous Nannofossil Biostratigraphy, Chapman and Hall, London, 1-315.

Burnett, J.A., 1998. Upper Cretaceous. In: Bown, P.R., (ed.), Calcareous nannofossil biostratigraphy. British Micropalaeontological Society Publications Series, Chapman and Hall/Kluwer Academic Publishers, 132-199.

Gale, A.S., Hancock, J.M., & Kennedy, W.J., 1999. Biostratigraphical and sequence correlation of the Cenomanian sucessions in Mangyshlak (W. Kazakhstan) and Crimea (Ukraine) with those in southern England. Bulletin de l’Institut Royal des Sciences Naturelles de Belgique, Sciences de la Terre, 69: supplement A, 67-86.

Gale, A.S., Kennedy, W.J., Burnett, J.A., Caron, M., & Kidd, B.E., 1996. The late Albian to Early Cenomanian succession at Mont risou near rosans (Hautes Alps, SE France); an integrated study (ammonites, inoceramids, planktonic foraminifera, nannofossils, oxygen and carbon isotopes). Cretaceous Research, 17: 515-606.

Gradstein, F.M., Ogg, J.G., & Hilgen, F.J., 2012. On The Geologic Time Scale. Newsletters on Stratigraphy 45 (2): 171-188.

Immel, H., Seyed-Emami, K., & Afshar-Harb, A., 1997. Kreide-Ammoniten aus dem iranischen teil des Koppeh-Dagh (NE-Iran). Zitteliana, 21: 159-190.

Immel, H., Seyed-Emami, K., 1985. Die Kreideammoniten des Glaukonitkalkes (O.Alb e O.Cenoman) des Kolah-Qazi-Gebirges südöstlich von Esfahan (Zentraliran). Zitteliana, 12: 87-137.

Mosavinia, A., & Wilmsen, M., 2011. Cenomanian Acanthoceratoidea (CretaceousAmmonoidea) from the Aitamir Formation (Koppeh Dagh, NE Iran): taxonomyand stratigraphic implications. Acta Geologica Polonica, 61: 175-192.

Mosavinia, A., Lehmann, J., & Wilmsen, M., 2014. Late Albian ammonites from the Aitamir Formation (Koppeh Dagh, NE Iran). Cretaceous Research, 50: 72-88.

Mosavinia, A., Wilmsen, M., Aryai, A., Shahida, M., & Lehmann, J., 2007. Mortoniceratinae (Ammonitina) from the Upper Albian (cretaceous) of the Atamir Formation, Koppeh Dagh Mountains, NE Iran. Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen, 246 (1): 83-95.

Owen, H.G., 1999. Correlation of Albian European and Tethyan ammonite zonations and the boundaries of the Albian Stage and substages: some comments. Scripta Geologica, 3: 129-149.

Perch-Nielsen, K., 1985. Mesozoic Calcareous Nannofossils. In: Bolli, H.M., Saunders, J.B., & Perch- Nielsen, K., (eds.), Plankton Stratigraphy. Cambridge University Press, Cambridge, 329-426.

Raisossadat, S.N., 2004. The ammonite family Deshayesitidae in the Kopet Dagh Basin, north-east Iran. Cretaceous Research, 25: 115-136.

Raisossadat, S.N., 2006. The ammonite family Parahoplitidae in the Sanganeh Formation of the Kopet Dagh Basin, north-eastern Iran.Cretaceous Research, 27: 907-922.

Roth, P.H., 1973. Calcareous nannofossils-Leg 17, Deep Sea drilling Project. In: Roth, P.H., & Herring, J.R., (eds.), Initial reports of the Deep Sea Drilling Project, 177: 696-796.

Roth, P.H., 1978. Cretaceous nannoplankton biostratigraphy and oceanography of the northwestern Atlantic Ocean. In: Benson, W.E., & Sheridan, R.E., (eds.), Initial Reports of the Deep Sea Drilling Project 44. U.S. Government Printing Office, Washington, 731-760.

Roth, P.H., 1983. Jurassic and Lower Cretaceous Calcareous Nannofossils in the Western North Atlantic (Site 534): Biostratigraphy, Preservation, and Some Observations on Biogeography and Paleoceanography. In: Sheridan, R.E., & Gradstein, F.M., (eds.), Initial Reports of the Deep Sea Drilling Project, 76: 587-621.

Seyed-Emami, K., & Aryai, A.A., 1981. Ammoniten aus dem unteren Cenoman von Nordostiran (Koppeh Dagh). Mitteilungen der Bayerischen Staatssammlung für Paläontologie und Historische Geologie, 21: 23-39.

Seyed-Emami, K., 1980. Parahoplitidae (Ammonoidea) aus dem Nordost und Zentral Iran. Neues Jahrbuch für Geologie und Paläeontologie, Monatshefte 1980, 719-737.

Seyed-Emami, K., Forster, R., & Mojtahedi, A., 1984. Ammoniten aus dem mittleren Cenoman von Nordost-Iran (Koppeh-Dagh). Neues Jahrbuch für Geologie und Paläontologie Monatshefte, 159-172.

Sissingh, W., 1977. Biostratigraphy of Cretaceous calcareous nannoplankton. Geologie en Mijnbouw, 56: 37-65.

Varol, O., 1992. Taxonomic revision of the Polycyclolithaceae and its contribution to Cretaceous biostratigraphy. Newsletters on Stratigraphy, 27: 93-127.

Wright, C.W., & Kennedy, W.J., 1987. The Ammonoidea of the lower chalk. Part II. Monograph of the Palaeontographical Society, London, 139: 127-218.