مورفوگروپ‌هاي فرامينيفري سازند قم در شرق سيرجان و جنوب غربي کاشان: کاربرد آنها در تفاسير ديرينه محيطي و پالئواکولوژيکي
محورهای موضوعی : شاخه های دیگر علوم زمین در ارتباط با زمین شناسی نفت
1 - دانشگاه تحصيلات تکميلي صنعتي و فناوري پيشرفته، کرمان
کلید واژه: سازند قم, اليگو-ميوسن, اپي¬, فونال, مورفولوژي پوسته, پالئواکولوژي, استراتژي تغذيه,
چکیده مقاله :
سازند قم مهم‌ترين سنگ مخزن و سنگ منشاء هيدروکربور در ايران مرکزي است. فرامينيفرها در حال حاضر پايه و اساس توانايي ما براي تعيين سن، تطابق و بررسي حوضه‌هاي رسوبي هستند که امروزه به عنوان کليدي براي رفاه اقتصادي جهان در نظر گرفته مي شوند. آناليز مورفوگروپ‌ها، به دليل مستقل بودن از تاکسونومي گونه‌ها و همچنين امکان مقايسه تجمعاتي با سنين مختلف ابزار مناسبي براي تفاسير اکولوژيکي و پالئواکولوژيکي محسوب مي‌گردد. مطالعه فرامينيفرهاي سازند قم در برش بوجان (شرق سيرجان، با سن روپلين- شاتين و 156 متر ضخامت) و برش ورکان (جنوب غربي کاشان؛ با سن روپلين و 190 متر ضخامت)، منجر به تشخيص هفت مورفوگروپ شد. شناسايي مورفوگروپ‌ها بر اساس مورفولوژي و معماري پوسته (شامل شکل کلي، الگوي پيچش و آرايش و تعداد حجرات)، و زيستگاه استنباطي که يا در سطح رسوبات زندگي مي‌کند يا در داخل رسوبات (اپيفونال/سطح زي يا اينفونال/درونزي) و استراتژي تغذيه (معلق/رسوب خوار، گياهخوار و غيره) استوار بوده است. در هر دو برش به‌طورکلي فرم‌هاي اپيفونال غالب بوده‌اند. آناليز مورفوگروپ‌ها بيانگر وجود نوساناتي در درصد مورفوگروپ-هاي غالب است، که خود بيانگر نوساناتي در شرايط اکولوژيکي محيط مي‌باشد. در برش بوجان در نهشته‌هاي روپلين مورفوگورپ هاي با ديواره پورسلانوز و در شاتين مورفوگورپ‌هاي با ديواره هيالين فراواني بيشتري دارند که بيانگر نهشته شدن بخش‌هاي پاييني در محيط‌هاي لاگوني و نهشته شدن بخش‌هاي بالايي برش (عمدتاً) در رمپ مياني است. اين تغيير چشمگير در طول زمان بيانگر افزايش تدريجي عمق حوضه، کاهش شوري، کاهش روشنايي و کاهش مواد مغذي است. غالب بودن مورفوگورپ‌هاي با ديواره هيالين در سرتاسر برش ورکان بيانگر رسوب‌گذاري اين برش (عمدتاً) در محيط‌هاي رمپ مياني با ميزان شوري نرمال دريايي و تحت شرايط نوري مزوفوتيک تا اليگوفوتيک مي‌باشد.
The Qom Formation is the main reservoir and source rock of hydrocarbons in central Iran. Foraminifera are now central to our ability to date, correlate and analyse the sedimentary basins that are currently key to the economic wellbeing of the world. Morphogroup analysis, due to independence of species level taxonomy, as wel as permit to comparison of assemblages of differing ages, is a useful tool for ecological and palaeoecological interpretation. It is independent of species level taxonomy and is thus relatively elementary to translate from one worker to another. Foramniferal study of the Qom Formation in the Bujan (eastern Sirjan; with Rupelin-Chattian in age and 156 m thickness) and Varkan (southwestern Kashan; with Rupelin in age and 190 m thickness) sections resulted in identification of seven morphogroups. The morphogroups were distinguished according to test/shell morphology and architecture (general shape, mode of coiling, and arrangement and number of chambers), inferred life habitat either living on the surface of the sediments or within the sediments (epifaunal and infaunal), and feeding strategy (suspension-feeder, herbivore, etc.). Generaly, epifaunal morphogroups were dominated in both study sections. The morphogroup analyses showed variations in the percentage of the dominant morphotypes, suggesting fluctuations in the paleoecological conditions. In the Bujan section, the Rupelin deposits are dominated by calcareous porcelaneous morphogroups; while the Chattian deposits are dominated by hyaline morphogroups, which indicates the lower and upper parts were deposited in inner ramp (lagoonal environments) and middle ramps, respectively. This significant change through time reffers to gradual increasing of the basin depth, decreasing the light intensity, reducing the salinity and decreacing the nutrient level. De dominance of the hyaline morphogroups throughout of the Varkan section is indicative of the deposition in middle ramp environments with normal salinity under meso-photic to oligo-photic conditions.
آقانباتي، ع.، 1383. زمين شناسي ايران، چاپ دوم. سازمان زمين شناشي و اکتشافات معدني کشور، تهران، 603 صفحه.
جلالي، م.، صادقي، ع.، آدابي، م.، 1396. ريز رخساره‌ها، محيط رسوبي و چينه نگاري سکانسي سازند قم در چاه يورته شاه-1 و برش سطحي موره كوه (جنوب تهران). فصلنامه پژوهش هاي چينه نگاري و رسوب شناسي، شماره 66، سال سي و سوم، 48-25.
رحيم زاده، ف.، 1373. زمين شناسي ايران، اليگوسن، ميوسن، پليوسن. سازمان زمين شناسي کشور، 311 ص.
سازمان جغرافيايي کشور، 1388، نقشه راههاي ايران، 1:2500000
Abaie I.L., Ansari, H.J., Badakhshan, A., Jaafari, A. 1964. History and development of the Alborz and Sarajeh fields of Central Iran. Bulletin of Iranian Petroleum Institute, 15: 561–574.
Alperin, M. I., Cusminsky, G. C., Bernasconi, E. 2011. Benthic foraminiferal morphogroups on the Argentine continental shelf, The Journal of foraminiferal Research 41 (2), 155–166.
Amirshahkarami, M., Vaziri-Moghaddam, H., Taheri, A., 2007. Sedimentary facies and sequence stratigraphy of the Asmari Formation at chaman-Bolbol, Zagros Basin, Iran. J Asian Earth Sci 29:947–959.
Bindiu, R., Filipescu, S., 2015. Foraminiferal biostratigraphy and paleoenvironments of the middle Eocene deposits from the northern part of the Tarcău Nappe (Eastern Carpathians, Romania). Studia UBB Geologia 59 (1-2), 45 – 59.
BouDagher-Fadel, M.K., 2018. Evolution and Geological Significance of Larger Benthic Foraminifera, 2st edition, UCL Press, London, p. 693.
Chan, S.A., Kaminski, M.A., Al-Ramadan, K., Babalola, L.O., 2017. Foraminiferal biofacies and depositional environments of the Burdigalian mixed carbonate and siliciclastic Dam Formation, Al-Lidam area, Eastern Province of Saudi Arabia. Palaeogeography, Palaeoclimatology, Palaeoecology 469, 1-16.
Corliss, B.H., Chen, C., 1988. Morphotype patterns of Norwegian deep-sea benthic foraminifera and ecological application. Geology 16, 716–719.
Duleba, W., Debenay, J. P., Eichler, B.B., Michaelovitch, M.M., 1999. Holocene Environmental and Water Circulation Changes: Foraminifer Morphogroups Evidence in Flamengo Bay (SP, Brazil). Journal of Coastal Research 15 (2), 554-571.
Heydari E, Hassanzadeh J, Wade WJ, Ghazi AM (2003) Permian–Triassic boundary interval in the Abadeh section of Iran with implications for mass extinction. Part 1—sedimentology. Palaeogeogr Palaeoclimatol Palaeoecol 193:405–423
Jones, R.W., Charnock, M.A., 1985. Morphogroups of agglutinated foraminifera. Their life position and feeding habits and potential applicability in paleoecological studies. Revue de Paleobiologie 4, 311–320.
Kender, S., Kaminski, M.A., Jones, R.W. 2009. Early to middle Miocene foraminifera from the deep-sea Congo Fan, offshore Angola. Micropaleontology 54, 477-568.
Koutsoukos, E. A. M., Hart, B.H., 1990. Cretaceous foraminiferal morphogroup distribution patterns, palaeocommunities and trophic structures: a case study from the Sergipe Basin, Brazil. Earth and Environmental Science Transactions of the Royal Society of Edinburgh: Earth Sciences 81, 221-246.
Mohammadi, E., 2020a. Sedimentary Facies and Depositional Environments of the Oligocene-Early Miocene Marine Qom Formation, Central Iran Back-Arc Basin, Iran (Northeastern Margin of the Tethyan Seaway). Carbonates and Evaporites 35. https://doi.org/10.1007/s13146-020-00553-0
Mohammadi, E., 2020b. Sedimentary facies and paleoenvironmental interpretation of the Oligocene larger-benthic-foraminifera-dominated Qom Formation in the northeastern margin of the Tethyan Seaway. Palaeoworld, 1-37. https://doi.org/10.1007/s13146-020-00553-0
Mohammadi, E., Hasanzadeh-Dastgerdi, M., Ghaedi, M., Dehghan, R., Safari, A., Vaziri-Moghaddam, H., Baizidi, C., Vaziri, M.R., Sfidari, E., 2013. The Tethyan Seaway Iranian Plate Oligo-Miocene deposits (the Qom Formation): distribution of Rupelian (Early Oligocene) and evaporate deposits as evidences for timing and trending of opening and closure of the Tethyan Seaway. Carbonates and Evaporites 28, 321-345.
Mohammadi, E., Vaziri, M.R., Dastanpour, M., 2015. Biostratigraphy of the Nummulitids and Lepidocyclinids bearing Qom Formation based on Larger Benthic Foraminifera (Sanandaj–Sirjan fore-arc basin and Central Iran back-arc basin, Iran). Arabian Journal of Geosciences 8, 403-423.
Mohammadi, E., Hasanzadeh-Dastgerdi, M., Safari, A., Vaziri-Moghaddam, H., 2019. Microfacies and depositional environments of the Qom Formation in Barzok area, SW Kashan, Iran. Carbonates Evaporites 34, 1293–1306.
Morley, C.K., Kongwung, B., Julapour, A.A., Abdolghafourian, M., Hajian, M., Waples, D., Warren, J., Otterdoom, H., Srisuriyon, K., Kazemi, H., 2009. Structural development of a major late Cenozoic basin and transpressional belt in central Iran: the Central Basin in the Qom-Saveh are. Geosphere, 4:325-362.
Murray, J.W., 1973. Distribution and ecology of benthic foraminiferids. Heinemann Educational Books, London. p. 274.
Murray, J.W., 2006. Ecology and Applications of Benthic Foraminifera. Cambridge University Press, Cambridge. p. 426.
Murray, J.W., Alve, E., Jones, B., 2011. A new look at modern agglutinated benthic foraminiferal morphogroups: their value in palaeoecological interpretation. Palaeogeography, Palaeoclimatology, Palaeoecology 309, 229-241.
Nagy, J., 1992. Environmental significance of foraminiferal morphogroups in Jurassic North Sea deltas. Palaeogeography, Palaeoclimatology, Palaeoecology 95, 111-134
Nagy, J., Grandstein, F.M., Kaminski, M.A., Holbourn, A.E., 1995. Foraminiferal morphogroups, paleoenvironments and new taxa from Jurassic to Cretaceous strata of Thakkhola, Nepal. In M.A. Kaminski et al. (Eds.): Proceedings of the Fourth International Workshop on Agglutinated Foraminifera. Grzybowski Foundation Special Publication 3, Krakow: Grzybowski Foundation, pp. 181–209.
Nikitenko, B.L., Reolid, M., Glinskikh, L., 2013. Ecostratigraphy of benthic foraminifera for interpreting Arctic record of Early Toarcian biotic crisis (northern Siberia, Russia). Palaeogeography, Palaeoclimatology, Palaeoecology 376, 200–212.
Preece R. C., Kaminski M. A., Dignes T. W. 1999. Miocene benthonic foraminiferal morphogroups in an oxygen minimum zone, offshore Cabinda. Geological Society, London, Special Publications, 153, 267-282, 1 January 1999,
Reolid, M., Nagy J., Rodríguez-Tovar F.J., Olóriz, F., 2008. Foraminiferal Assemblages as Palaeoenvironmental Bioindicators in Late Jurassic Epicontinental Platforms: Relation with Trophic Conditions. Acta Palaeontologica Polonica 53(4), 705-722.
Reuter, M., Piller, W.E., Harzhauser, M., Mandic, O., Berning, B., Rogl, F., Kroh, A., Aubry, M.P., Wielandt-Schuster, U., Hamedani, A., 2009. The Oligo-/Miocene Qom Formation (Iran): evidence for an early Burdigalian restriction of Tethyan Seaway and closure of its Iranian gateways. International Journal of Earth Sciences 98, 627–650.
Sarbandi Farahani, T., Reolid, M., Yazdi, M., Majidifard, M.R., 2018. Benthic foraminiferal assemblages of the Middle and Upper Jurassic sediments from the northeastern Alborz and western Koppeh Dagh, Iran: Systematic palaeontology and palaeoecology. Annales de Paléontologie 104, 249–265.
Sepehr, M., Cosgrove, J.W., 2004. Structural framework of the Zagros Fold-Thrust Belt, Iran. Marine and Petroleum Geology. 21: 829-843.
Severin, K.P., 1983. Test morphology of benthic foraminifera as a discriminator of biofacies. Marine Micropaleontology 8, 65-76.
Schuster, F., Wielandt, U., 1999. Oligocene and Early Miocene coral faunas from Iran: palaeoecology and palaeobiogeography. International Journal of Earth Science 88, 571–581.
Setoyama, E., Kaminski, M.A., Tyszka, J., 2017. Late Cretaceous-Paleogene foraminiferal morphogroups as palaeoenvironmental tracers of the rifted Labrador Margin, northern proto-Atlantic. Grzybowski Foundation Special Publication 22, 179–220.
Stojanova, V., Petrov, G., 2018. Foraminiferal Assemblages as Palaeoenvironmental Bioindicators in Late Jurassic Epicontinental Platforms: Relation with Trophic Conditions. Acta Palaeontologica Polonica, 53(4), 705-722.
Szydło, A., 2005. Benthic foraminiferal morphogroups and taphonomy of the Cieszyn beds (Tithonian-Neocomian, Polish Outer Carpathians). Studia Geologica Polonica 124, 199-204.
Tyszka J. 1994. Response of Middle Jurassic benthic foraminiferal morphogroups to dysoxic/anoxic conditions in the Pieniny Klippen Basin, Polish Carpathians. Palaeogeography, Palaeoecology, Palaeoclimatology 110, 55–81.
Xu, G., Zhang, S., Li, Z., Song, L., Liu, H., 2007. Sequence stratigraphy of a back-arc basin: a case study of the Qom formation in the Kashan Area, Central Iran. Acta Geologica Sinica (English edition), 81: 488–500.