زیست‌چینه‌نگاری و چینه‌نگاری سکانسی نهشته‌های کربونیفر زیرین زون البرز بر مبنای فرامینیفرهای بنتیک و ژئوشیمی ایزوتوپی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 گروه زمین‌شناسی، دانشکده علوم زمین، دانشگاه تحصیلات تکمیلی علوم پایه زنجان، زنجان، ایران

2 گروه زمین‌شناسی، دانشکده علوم، دانشگاه زنجان، زنجان، ایران

3 گروه زمین‌شناسی، دانشکده علوم زمین، دانشگاه شهید بهشتی، تهران، ایران

چکیده

توزیع و هندسه سازند مبارک به سن تورنزین- ویزئن حاکی از رسوبگذاری بر روی رمپ کربناتی هموکلاین نسبتاً کم انرژی با زاویه کم است. این تفسیر براساس ویژگی‌های رخساره‌های تشکیل دهنده و روابط جانبی و عمودی تدریجی بین رخساره‌های رسوبی است. براساس تجزیه و تحلیل رخساره‌ها و مجموعه‌های رخساره‌ای، می‌توان چهار مجموعه رخساره‌ای برای رمپ کربناتی مبارک در نظر گرفت که عبارتند از محیط‌های رسوبی حوضه، رمپ خارجی (مجموعه‌های ساب‌تایدال عمیق)، رمپ میانی (مجموعه‌های ساب‌تایدال کم‌عمق) و رمپ داخلی. سازند مبارک از 4 سکانس رسوبی (S1- S4) تشکیل شده است که حاصل فعل و انفعال بین تغییرات سطح آب دریا و شرایط اقلیمی می‌باشند. این سکانس‌ها شامل پکیج‌های پس‌نشسته1 (دسته رخساره پیش‌رونده (TST)) و پیش‌نشسته2 (دسته رخساره ترازبالا (HST)) هستند. زیست‌چینه‌نگاری سازند مبارک براساس زیرتقسیم‌بندی زون‌های فرامینیفری می‌سی‌سی‌پین3 (MFZ) انجام گرفته، 9 بایوزون (MFZ1- MFZ9) متعلق به زیرآشکوب‌های هاستارین، ایوورین و مولینیسین را نشان می‌دهد. انطباق خوب دسته‌رخساره‌های TST، HST و ژئوشیمی ایزوتوپ کربن 13 (δ13C) حاکی از آن است که نوسانات سطح آب دریا به عنوان مکانیسم اصلی، منجر به تغییر مقادیر ایزوتوپ کربن 13 (δ13C) روی رمپ کربناتی مبارک شده است.  به طور کلی، تلفیق این مجموعه داده‌ها می‌تواند مبنایی برای انطباق سکانس‌های رسوبی در مقیاس ناحیه‌ای ناشی از تغییرات سطح دریای جهانی قابل استفاده باشد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Biostratigraphy and sequence stratigraphy of the Lower Carboniferous deposits in the Alborz zone based on benthic foraminifera and isotopic geochemistry

نویسندگان [English]

  • Seyedeh Parvin Mousavi Taher 1
  • Aram Bayet-Goll 1
  • Najmeh Etemad- Saeed 1
  • Mehdi Daraei 1
  • Afshin Zohdi 2
  • Javad Rabbani 2
  • Fatemeh Mohammad Zadeh 3
1 Department of Geology, Faculty of Earth Sciences, Institute for Advanced Studies in Basic Sciences (IASBS), , Zanjan, Iran
2 Department of Geology, Faculty of Science, University of Zanjan, Zanjan, Iran
3 Department of Geology, Faculty of Earth Sciences, Shahid Beheshti University, Tehran, Iran
چکیده [English]

Introduction
Understanding the cyclical nature of changes in sea-level regime leads to awareness of historical land events. In the functional basin, it leads to predictions about the presence of source rocks and hydrocarbon reservoirs in sedimentary sequences. Cycles are formed during a process of falling to rising sea level. The study of sedimentary cycles and understanding the causes of their formation is done in the form of cyclic stratigraphy. Relative changes in sea level were the first active mechanism for the formation of marine sedimentary cycles and sequences. In general, cyclic sedimentary patterns are the product of tectonic and climatic processes, followed by global and local changes in sea level.
Materials and methods
 The study of cycles and their formation controlling factors in this article has been done using qualitative studies such as field and laboratory evidence of carbonate deposits of Mobarak Formation. In order to achieve the types of cycles and processes affecting their formation, facies and facies association, depositional environment, isotopic geochemistry and relative sensors were determined using benthic foraminifera as well as sequence stratigraphy.
Discussions and findings
Studies on field evidence such as sediment erosion pattern, lateral continuity of layers, sedimentary and biological structures, as well as petrographic studies of facies and facies association obtained in this formation, four third-order sedimentary sequences of S1 to S4 were identified. The sequences did not have a low- stand systems tract (LST) and were identified by a highstand systems tract (HST) and transgressive systems tract (TST) that could be controlled by the interaction between eustatic sea-level changes and climate conditions. Depositional sequences show retro-gradational (transgressive systems tract) and prograditional (high-stand systems tract) stacking patterns. Together, these sequences cover a large regressive cycle from the basins / open marine facies to the tidal zone. The distribution and geometry of the Tournaisian-Visean Mobarak Formation imply deposition on a low-angle, relatively low-energy homoclinal carbonate ramp. This interpretation is based on the characteristics of the constituting facies and their gradual lateral and vertical changes. Based on the facies analysis and their associations, four facies’ belts (associations) can be recognized, i.e., basinal environments, outer ramp (deep subtidal associations), mid ramp (shallow subtidal associations), and inner ramp. The study of fossils in sedimentary deposits is one of the oldest and most common methods for determining the relative age of sediments.  By examining the distribution of fossils in stratigraphic units and organizing stratigraphy in units based on their fossil content, the age of the units can be determined. According to this, the bio-stratigraphic investigation shows 9 biozones (MFZ1- MFZ9) belonging to the Hastarian, Ivorian, and Moliniacian sub-stages based on the classification of Mississippian Foraminiferal Zones (MFZ). A good agreement between TSTs and HSTs, and δ13C chemo-stratigraphy implies that sea level fluctuations are the main mechanism that control the δ13C fluctuations in the Mobarak Formation.  Integration of these data indicates that the sequences has been driven by the eustatic sea-level changes and suggests a basic for the regional sequence stratigraphic correlations. The relative ages of the studied calcareous strata were obtained in the Kalariz sections. They are related to the three sub-stage of Hastarian, Ivorian, and Moliniacian. In addition, the study of oxygen and carbon isotopes, which was performed in the Kalariz section, was used to determine the sequence levels and the long-term temperature of the Lower Carboniferous deposits. Therefore, by studying the isotopic values of oxygen and carbon, it is found that the analyzed samples of this formation experienced the least amount of alteration and diagenesis and were close to the waters of the lower Carboniferous Sea.
Conclusion
In this study, 12 main facies were identified and classified into 5 facies association. These facies association are spread on a homoclinal ramp carbonate platform. Examining the field and laboratory evidence, four third-order sedimentary sequences S1, S2, S3 and S4 were identified by the high-stand systems tract (HST) and transgressive systems tract (TST) categories. According to the subdivision of Mississippian foraminiferal zones (MFZ), 9 biozones (MFZ1- MFZ9) were identified in this study, which belong to the subgroups of Hastarian, Ivorian and Moliniacian. In addition, by studying the isotopic values ​​of oxygen and carbon, it was found that the analyzed samples of this formation experienced the least amount of alteration and diagenesis and were close to the waters of the lower Carboniferous Sea. Finally, the studies showed that the main mechanism controlling the fluctuations of isotopic values, cycles and sequences of the third order are the Eustatic fluctuations of the water surface.

کلیدواژه‌ها [English]

  • Sequence stratigraphy
  • Biostratigraphy
  • Isotopic geochemistry
  • Benthic foraminifera
  • Lower Carboniferous
-آدابی، م.ح. و ارباب، ب.، 1381. پتروگرافی، تعیین کانی شناسی اولیه و بازسازی محیط رسوبی نهشته‌های کربناته سازند مبارک (براساس روند تغییرات ژئوشیمیائی در نـاحیه آرو در البرز مرکزی)، نشریه علوم، شماره ۱۸(۵۸)، ص ۶۳-۸۷
-آقانباتی، ع.، 1383. زمین‌شناسی ایران، انتشارات سازمان زمین‌شناسی و اکتشافات معدنی کشور، 606 ص.
-ارباب، ب.، 1380. پتروگرافی، ژئوشیمی و محیط رسوبی نهشته‌های پالئوزوئیک بالایی منطقه آرو (البرز مرکزی)، پایان‌نامه کارشناسی ارشد، دانشگاه شهید بهشتی.
-مصدق، ح.، 1379. میکروفسیل‌ها، رخساره‌ها، محیط‌های رسوبی و چینه‌نگاری سکانسی سازند مبارک (کربونیفرزیرین) در البرز مرکزی، رساله دکتری، دانشگاه تربیت معلم.
-موسوی طاهر، س.پ.، بایت‌گل، ی.، اعتماد سعید، ن. و دارائی، م.، ربانی، ج.، 1399. مطالعه عناصر رخساره‌ای و محیط رسوبگذاری نهشته‌های تورنزین- ویزئن زون البرز مرکزی- سازند مبارک، پنجمین همایش انجمن رسوب‌شناسی ایران، ص 832-838.
 
 
 
-Afshar-Harb, A., 1979. The stratigraphy, tectonics and petroleum geology of the Kopeh Dagh region, Northern Iran (Doctoral dissertation, Imperial College London (University of London), 316 p.
-Afshar-Harb, A., 1994. Geology of Kopeh Dagh. Treatise on the Geology of Iran, v. 11, p. 1-275
-Bagheri, S. and Stampfli, G.M., 2008. The Anarak, Jandaq and Posht-e-Badam metamorphic complexes in central Iran: New geological data, relationships and tectonic implications. Tectonophysics, v. 451(1), p. 123-155.
-Bayet-Goll, A., Geyer, G., Wilmsen, M., Mahboubi, A. and Moussavi-Harami, R., 2014. Facies architecture, depositional environments and stratigraphy of the Middle Cambrian Fasham and Deh-Sufiyan formations in the central Alborz, Iran. Facies, v. 60, p. 815-841.
-Bayet-Goll, A., De Carvalho, C.N., Mahmudy-Gharaei, M.H. and Nadaf, R., 2015. Ichnology and sedimentology of a shallow marine Upper Cretaceous depositional system (Neyzar Formation, Kopet-Dagh, Iran): Palaeoceanographic influence on ichnodiversity. Cret Res, v. 56, p. 628-646.
-Bayet-Goll, A., Geyer, G. and Daraei, M., 2018a. Tectonic and eustatic controls on the spatial distribution and stratigraphic architecture of late early Cambrian successions at the northern Gondwana margin: the siliciclastic-carbonate successions of the Lalun Formation in central Iran. Marine and Petroleum Geology, v. 98, p. 199-228.
-Bayet-Goll, A., Shirezadeh-Esfahani, F., Daraei, M., Monaco, P., Sharafi, M. and Akbari Mohamadi, A., 2018b. Cyclostratigraphy across a Mississippian carbonate ramp in the Esfahan-Sirjan Basin, Iran: implications for the amplitudes and frequencies of sea-level fluctuations along the southern margin of the Paleotethys. International Journal of Earth Sciences, v. 107, p. 2233-2263.
-Bayet-Goll, A., Esfahani, F.S., Daraei, M., Monaco, P., Sharafi, M. and Mohammadi, A. A., 2018. Cyclostratigraphy across a Mississippian carbonate ramp in the Esfahan–Sirjan Basin, Iran: implications for the amplitudes and frequencies of sea-level fluctuations along the southern margin of the Paleotethys. International Journal of Earth Sciences, p. 1-31.
-Bayet-Goll, A., Daraei, M., Taher, S.P.M., Etemad-Saeed, N., de Carvalho, C.N., Zandkarimi, K. and Nasiri, Y., 2020. Variations of the trace fossil Zoophycos with respect to paleoenvironment and sequence stratigraphy in the Mississippian Mobarak Formation, northern Iran. Palaeogeography, Palaeoclimatology, Palaeoecology, 109 p.
-Brenckle, P.L., Gaetani, M., Angiolini, L. and Bahrammanesh, M., 2009. Refinements in biostratigraphy, chronostratigraphy, and paleogeography of the Mississippian (Lower Carboniferous) Mobarak Formation, Alborz Mountains, Iran. GeoArabia, v. 14(3), p. 43-78.
-Falahatgar, M. and Mosaddeg, H., 2012. Microfacies and palaeoenvironments of the Lower Carboniferous Mobarak Formation in the Kiyasar section, Northern Iran, Acta Geologica Sinica, v. 86, p. 141-162.‏
-Frauenstein, F., Veizer, J., Beukes, N., Van Niekerk, H.S. and Coetzee, L.L., 2009. Transvaal Supergroup carbonates: Implications for Paleoproterozoic δ18O and δ13C records, Precambrian Research, v. 175, p. 149-160.
-Haq, B.U. and Schutter, S.R., 2008. A chronology of Paleozoic sea-level changes, Science, v. 322, p. 64-68.
-Hoefs, J., 2009. Stable Isotope Geochemistry, 6rd Edition, Springer-Verlag, Berlin, 208 p.
-Kietzmann, D.A., Palma, R.M., Riccardi, A.C., Martín-Chivelet, J. and López-Gómez, J., 2014. Sedimentology and sequence stratigraphy of a Tithonian-Valanginian carbonate ramp (Vaca Muerta Formation): A misunderstood exceptional source rock in the Southern Mendoza area of the Neuquén Basin, Argentina. Sediment. Geol, v. 302, p. 64-86.
-Lee, H.S. and Chough, S.K., 2011. Depositional processes of the Zhushadong and Mantou formations (Early to Middle Cambrian), Shandong Province, China: Roles of archipelago and mixed carbonate siliciclastic sedimentation on cycle genesis during initial flooding of the North China Platform. Sedimentology, v. 58(6), p. 1530-1572.
-Muttoni, G., Mattei, M., Balini, M., Zanchi, A., Gaetani, M. and Berra, F., 2009. The drift history of Iran from the Ordovician to the Triassic. In: Brunet, M.F., Wilmsen, M., Granath, J.W. (Eds.), South Caspian to Central Iran Basins. Geological Society, London, Special Publications, v. 312, p. 7-29.
-Osleger, D. and Read, J.F., 1991. Relation of eustasy to stacking patterns of meter-scale carbonate cycles, late Cambrian, USA. J Sediment Pet, v. 61(7), p. 1225-1252.
-Palma, R.M., López-Gómez, J. and Piethé, R.D., 2007. Oxfordian ramp system (La Manga Formation) in the Bardas Blancas area (Mendoza Province) Neuquén Basin, Argentina: Facies and depositional sequences. Sedimentary Geology, v. 195(3-4), p. 113-134.
-Veizer, J., Ala, D. and Azmy, K., 1999. 87Sr/86Sr, δ13C and δ18O evolution of Phanerozoic seawater. Chem Geol, v. 79, p. 351-343.
-Zandkarimi, K., Vachard, D., Najafian, B., Mosaddegh, H. and Ehteshami‐Moinabadi, M., 2019. Mississippian lithofacies and foraminiferal biozonation of the Alborz Mountains, Iran: Implications for regional geology. Geological Journal, v. 54(3), p. 1480-1504.