رخداد غیرهوازی اقیانوسی مرز سنومانین – تورونین در خاور حوضه کپه‎داغ (برش امیرآباد) با تأکید بر اجتماعات نانوفسیلی

نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانشجوی دکترا، گروه زمین‎شناسی، دانشکده علوم زمین، دانشگاه شهید بهشتی، تهران، ایران

2 دانشیار، گروه زمین‎شناسی، دانشکده علوم زمین، دانشگاه شهید بهشتی، تهران، ایران

3 استادیار، گروه زمین‎شناسی، دانشگاه پیام نور مشهد، مشهد، ایران

چکیده

در این مطالعه رسوبات مرز سازندهای آیتامیر و آبدراز در برش امیرآباد در خاور منطقه کپه‌داغ بررسی شدند. بر پایه نانوفسیل‌های آهکی برای این محدوده، بر پایه زیست‌زون‌بندی NC، سن آلبین پسین تا تورونین پسین تعیین شده است. شواهد بسیاری مانند تغییرات پالئواکولوژیکی و تغییر در میزان تدفین کربن آلی، ثبت رخداد غیر هوازی اقیانوسی مرز سنومانین- تورونین (OAE2) را در رسوبات مربوط به این بخش تأیید می‌کند. رخدادهای غیرهوازی بیشتر در اثر افزایش حاصلخیزی و تولید رخ می‌دهند که این شرایط بیشتر با افزایش تدفین کربن آلی در رسوبات همراه است. مطالعات پالئواکولوژیکی در طول توالی امیرآباد، شامل کاهش فراوانی جنس‌های Broinsonia و Biscutum در رسوبات مربوط به ابتدای سنومانین پسین و افزایش جنس Watznaueria در این محدوده زمانی است که شرایط محیطی الیگوتروف را پیشنهاد می‌کند. در بخش انتهایی سنومانین پسین و مرز سنومانین- تورونین با افزایش فراوانی نسبی گونه‌های شاخص آب‌های سطحی مغذی مانند جنس Biscutum و افزایش شاخص حاصلخیزی (Biscutum+Zeugrhabdotus)/Watznaueria حاکمیت شرایط محیطی یوتروف را محتمل می‌کند. حضور نداشتن جنس Nannoconus که در شرایط غیرهوازی غایب است نیز می‌تواند از نشانه‌های محیطی ثبت OAE2 باشد. با درنظر گرفتن میزان کربن آلی کل موجود در رسوبات که در محدوده تعیین شده روند افزایشی دارد و نشانه‎های پالئواکولوژیکی یاد شده، ثبت رخداد غیرهوازی اقیانوسی سنومانین پسین در رسوبات برش امیرآباد در خاور منطقه کپه‌داغ قطعی به نظر می‌رسد. این رخداد جهانی اگر چه در مناطق مختلفی در شیل‌های سیاه اقیانوسی گزارش شده؛ ولی در مقاطع بسیاری، به‎ویژه در خاور حوضه تتیس، در رسوبات مربوط به آب‌های کم‎ژرفا نیز به ثبت رسیده است. توالی رسوبات شیلی- مارنی منطقه کپه‌داغ را می‌توان در ادامه روند جهانی آن و  به عنوان خاوری‌ترین منطقه از حوضه تتیس نام برد که شرایط غیر هوازی اقیانوسی سنومانین پسین OAE2 در حوضه‌ای به نسبت کم‌ژرفا رخ داده است.

کلیدواژه‌ها


عنوان مقاله [English]

The Cenomanian – Turonian boundary oceanic anoxic event in East of Kopet-dagh basin (Amirabad section) with emphasis on calcareous nannofossils

نویسندگان [English]

  • N Mousavi 1
  • A L.Kani 2
  • A Mosavinia 3
1 Ph.D. Student, Department of Geology, Faculty of Earth Science, Shahid Beheshti University, Tehran, Iran
2 Associate Professor, Department of Geology, Faculty of Earth Science, Shahid Beheshti University, Tehran, Iran
3 Assistant Professor, Department of Geology, Payame Noor University, Mashhad, Iran
چکیده [English]

In this study the succession comprising Aitamir and Abderaz Formation boundary is investigated along Amir Abad section in eastern Koppeh-Dagh region. Based on Calcareous nannofossils and NC biozonation scheme, Late Albian to Late Turonian time of deposition is estimated for the measured succession. There is some evidence such as paleoecological changes and increase in organic carbon burial, enabling recognition of the Cenomanian – Turonian Oceanic Anoxic Event (OAE2) in this section. Anoxic events often occur as a result of high productivity leading to increased burial of organic matter. Paleoecological trends recorded including decrease in abundance of Broinsonia spp. and Biscutum spp. and increase in Watznaueria spp. at the beginning of the late Cenomanian interval suggest prevalence of oligotrophic condition during this interval of time. In the late Late Cenomanian and Cenomanian-Turonian boundary intervals, the increase in relative abundance of surface water high fertility markers such as Biscutum spp. and the increase of fertility index i.e. (Biscutum+Zeugrhabdotus)/Watznaueria, point to  amore eutrophic condition. The absence of Nannoconus spp., which are not seen in anoxic conditions, is another evidence of OAE2. The rising trend of total organic carbon content in the Late Cenomanian part of the sedimentary succession and the mentioned paleoecological evidences, suggest presence of Late Cenomanian Oceanic Anoxic Event in eastern Koppeh-Dagh. Although this global event is mostly reported from oceanic black shales, in some sections especially in the east of Tethys, it is sometimes recorded in shallow water sediments. Shale and marl succession in Koppeh-Dagh region can be considered as the continuation of their global trend in the eastern-most part of the Tethyan realm where the Late Cenomanian Oceanic Anoxic Event (OAE2) has occurred in a rather shallow environment of deposition.

کلیدواژه‌ها [English]

  • Abderaz Formation
  • Aitamir Formation
  • Calcareous Nannofossils
  • Koppeh-Dagh
  • OAE2

افشارحرب، ع.، ١٣٧٣- زمین‌شناسی ایران، زمین‌شناسی کپه‌داغ، سازمان زمین‌شناسی کشور، ٢٧۵ص.

رئیس‌السادات، ن. و محبوبی، ا.، 1389- بررسی ایزوتوپ‌های پایدار کربن و اکسیژن در سازندهایسرچشمه و سنگانه در غرب حوضه کپه‌داغ، نشریه علمی- پژوهشی رخساره‌های رسوبی، دوره 3، ش. 2، صص. 88 تا 98.

عقیقی، ر.، موسوی حرمی، ر. ، محبوبی، ا. و خانه‌باد، م.، 1392- محیط رسوبی رسوبات مخلوط آواری- کربناته سازند آیتامیر (ناحیه بزنگان- شرق حوضه کپه‌داغ)، سی و دومین گردهمایی و نخستین کنگره بین‌المللی تخصصی علوم زمین، سازمان زمین‌شناسی و اکتشافات معدنی کشور.

فروغی، ف. و صادقی، ع.،  1385- بیوستراتیگرافی سازند آبدراز در مقطع چینه شناسی روستای طاهرآباد ( شرق حوضه کپه‎داغ) بر مبنای فرامینیفرهای پلانکتونی- سازمان زمین‌شناسی و اکتشافات معدنی ایران. ش 4، صص. 47 تا 63 .

ماهانی‌پور، ا.، رییس‌السادات، ن. و لطفعلی کنی، ا.، 1391الف- بررسی رخداد غیرهوازی اقیانوسی آپتین پیشین بر اساس نانوفسیل‌های آهکی و آمونیت‌ها در غرب منطقه کپه‌داغ. پژوهشهای چینه‌نگاری و رسوب‌شناسی، ش. ٤٧، صص. 83 تا 96.

ماهانی‌پور، ا.، لطفعلی کنی، ا. و آدابی، م.، 1391ب- چینه‌نگاری ایزوتوپ کربن رسوبات آپتین زیرین غرب منطقه کپه داغ در ایران(برش تکل‌کوه). فصلنامه زمین‌شناسی ایران، ش. 24، صص. 67  تا 78.

محبوبی، ا. و محمدیان، ح.، ١٣۹١- ارتباط افق‌های پرفسیل (shell beds) و اثرفسیل‌های آلبین- سنومانین سازند آیتامیر در تاقدیس امیرآباد- شمال شرق مشهد، پژوهشهای چینه‌نگاری و رسوب‌شناسی، ش. ٤٧، صص. 1 تا ٢٤.

 Arthur, M. A., Dean, W. A. and Pratt, L. M., 1988- Geochemical and climatic effects of increased marine organic burial at the Cenomanian/Turonian boundary. Nature 335, 714-717.

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

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

Bown, P. R., 1998- Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publications Series. Chapman and Hall/Kluwer Academic Publishers, pp. 16–28.

Bralower, T. J., 1988- Calcareous nannofossil biostratigraphy and assemblages of the Cenomanian-Turonian boundary interval: implications for the origin and timing of oceanic anoxia. Paleoceanography 3, 275–316. DOI: 10.1029/PA003i003p00275

Bralower, T. J., Leckie, R. M., Sliter, W. V. and Thierstein, H. R., 1995- An integrated Cretaceous timescale: in Berggren, W. A., Kent, D. V., Aubry, M. -P., and Hardenbol, J., eds., Geochronology Time Scales and Global Stratigraphic Correlation, Society of Economic Paleontologists and Mineralogists, Special Publication, v. 54, p. 65-79.

Burnett, J. A., Gallagher, L. T., Hampton, M. J., 1998- Upper Cretaceous. In: Bown, P.R. (Ed.), Calcareous nannofossil biostratigraphy. British Micropalaeontological Society Publications Series. Chapman and Hall/Kluwer Academic Publishers, pp. 132–199.

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, pp. 132–199.

Clarke, L. J. and Jenkyns, H. C., 1999- New oxygen isotope evidence for long-term Cretaceous climatic change in the Southern Hemisphere. Geology 27, 699-702. DOI: 10.1130/0091-7613(1999)​027​2.3.CO;2

Coccioni, R., Erba, E. and Premoli Silva, I., 1992- Barremian– Aptian calcareous plankton biostratigraphy from the Gorgo a Cerbara section (Marche, central Italy) and implications for plankton evolution. Cretaceous Research. 13, 517– 537.

Corbett, M. J. and Watkins, D. K., 2013- Calcareous Nannofossil Paleoecology of the mid-Cretaceous Western Interior Seaway and Evidence of Oligotrophic Surface Waters during OAE2. Palaeogeography, Palaeoclimatology, Palaeoecology, 392. 510-523. DOI: 10.1016/j.palaeo.2013.10.007.

Davis, H. R., Byers, C. W. and Pratt, L.M., 1989- Depositional mechanisms and organic matter in Mowry Shale, (Cretaceous) Wyoming. American Association of Petroleum Geologist 73, 1103–1116.

Dodsworth, P., 2004- The palynology of the Cenomanian-Turonian (Cretaceous) boundary succession at Aksudere in Crimea, Ukraine, Palynology 28, 129-141. DOI: http://dx.DOI.org/10.2113/28.1.129.

Elrick, M., Molina-Garza, R., Duncan, R. and Snow, L., 2008- C-isotope stratigraphy and paleoenvironmental changes across OAE2 (mid-Cretaceous) from shallow-water platform carbonates of southern Mexico. Earth and Planetary Science Letters, 1-12. DOI: 10.1016/j.epsl.2008.10.020

El-Sabbagh, A. M., Tantawy, A. Keller, G., Khozyem, H., Spangenberg, J., Adatte, T. and Gertsch, B., 2011- Stratigraphy of the Cenomanian-Turonian Oceanic Anoxic Event OAE2 in shallow shelf sequences of NE Egypt. Cretaceous Research 32,705-722.DOI: 10.1016/j.cretres.2011.04.006

Erba, E., 1994- Nannofossils and superplumes: the early Aptian ‘‘nannoconid crisis’’. Paleoceanography 9, 483–501.

Erba, E., 2004- Calcareous nannofossils and Mesozoic anoxic events. Marine Micropaleontology 52, 85–106. DOI: 10.1016/ j.marmicro.2004.04.007

Erbacher, J., Friedrich, O., Wilson, P. A., Birch, H. and Mutterlose, J., 2005- Stable organic carbon isotope stratigraphy across Oceanic Anoxic Event 2 of Demerara Rise, Western Tropical Atlantic. Geochemistry, Geophysics & Geosystems 6, 1-9. DOI:10.1029/2004GC000850.

Erbacher, J., Huber, B. T., Norris, R. D. and Markey, M., 2001- Increased thermohaline stratification as a possible cause for an ocean anoxic event in the Cretaceous period. Nature 409, 325-327. DOI: 10.1038/35053041

Erbacher, J., Thurow, S. and Littke, R., 1996- Evolution patterns of radiolaria and organic matter variations: A new approach to identify sea-level changes in mid-Cretaceous pelagic environments Geology, 24, 499-502. DOI: 10.1130/0091-7613(1996)0242.3.CO;2.

Forster, A., Schouten, S., Baas, M. and Sinninghe Damsté, J. S., 2007- Mid-Cretaceous (Albian-Santonian) sea surface temperature record of the tropical Atlantic Ocean. Geology 35, 919-922. DOI: 10.1130/G23874A.1.

Friedrich, O., Erbacher, J. and Mutterlose, J., 2006- Paleoenvironmental changes across the Cenomanian/Turonian Boundary Event (Oceanic Anoxic Event 2) as indicated by benthic foraminifera from the Demerara Rise (ODP Leg 207). Revue de la micropaleontology 49, 121-139.

Gale, A. S., Jenkyns, H. C., Kennedy, W. J. and Corfield, R. M., 1993- Chemostratigraphy versus biostratigraphy: data from around the Cenomanian–Turonian boundary. Jornal of the Geological Society 150, 29-32. DOI: 10.1144/gsjgs.150.1.0029.

Gale, A. S., Smith, A. B., Monks, N. E. A., Young, J. A., Howard, A., Wray. D. S. and Huggett, J. M., 2000- Marine biodiversity through the Late Cenomanian–Early Turonian: palaeoceanographic controls and sequence stratigraphic biases. Journal of the Geological Society of London 150, 29-32.

Gertsch, B., Adatte, T., Keller, G., Tantawy, A. A., Berner, Z., Mort, H. P. and Fleitmann, D., 2010- Middle and late Cenomanian Oceanic Anoxic Events in shallow and deeper shelf environments of NW Morocco. Sedimentology 57, 1430e1462. DOI: 10.1111/j.1365-3091.2010.01151.x.

Gradstein, F. M., Ogg, J. G. and Hilgen, F. J., 2012- On The Geologic Time Scale. Newsletters on Stratigraphy 45 (2) , p. 171 – 188 . DOI : 10.1127/0078-0421/2012/0020.

Haq, B. U., Hardenbol, J. and Vail, P. R., 1987- Chronology of fluctuating sea levels since the Triassic. Science 235, 1156-1167. DOI: 10.1126/science.235.4793.1156.

Hardas, P. and Mutterlose, J., 2006- Calcareous nannofossil biostratigraphy of the Cenomanian/Turonian boundary interval of ODP Leg 207 at the Demerara Rise. Revue de la micropaleontology 49, 165-179.

Hardas, P. and Mutterlose, J., 2007- Calcareous nannofossil assemblages of Oceanic Anoxic Event 2 in the equatorial Atlantic: Evidence of an eutrophication event. Marine Micropaleontology 66, 52–69.

Hardas, P., Mutterlose, J., Friedrich, O. and Erbacher, J., 2008- A major biotic event in the middle Cenomanian equatorial Atlantic. In: Hardas, P. (Ed.) 2008, The response of  calcareous nannofossils to Oceanic Anoxic Event 2 and the Middle Cenomanian Event in the tropical Atlantic: Biostratigraphy and palaeoceanographic implications, pp. 84-129.

Herrle, J. O. and Mutterlose, J., 2003- Calcareous nannofossils from the Aptian–Lower Albian of southeast France: palaeoecological and biostratigraphic implications. Cretaceous Research 24, 1-22. DOI:10.1016/S0195-6671(03)00023-5.

Herrle, J. O., Pross, J., Friedrich, O., Kößler, P. and Hemleben, C., 2003- Forcing mechanisms for mid-Cretaceous black shale formation; evidence from the Upper Aptian and Lower Albian of the Vocontian Basin (SE France). Palaeogeography, Palaeoclimatology, Palaeoecology, 190, 399-426. DOI:10.1016/S0031-0182(02)00616-8.

Hetzel, A., Böttcher, M. E., Wortmann, U. G. and Brumsack, H. J., 2009- Paleo-redox conditions during OAE 2 reflected in Demerara Rise sediment geochemistry (ODP leg 207). Palaeogeography, Palaeoclimatology, Palaeoecology 273, 302–328.

Holbourn, A. and Kuhnt, W., 2002- Cenomanian-Turonian palaeoceanographic change on the Kerguelen Plateau: a comparison with Northern Hemisphere records. Cretaceous Research, 23, 333-349. DOI: 10.1006/cres.2002.1008.

Huber, B. T., Leckie, R. M., Norris, R. D., Bralower, T. J. and CoBabe, E., 1999- Foraminiferal assemblage and stable isotopic change across the Cenomanian-Turonian boundary in the subtropical North Atlantic. Journal of Foraminiferal Research. 29:392-417.

Huc, A. Y., 1988- Aspects of depositional processes of organic matter in sedimentary basins. In: Mattavelli, L. and Novelli, L. (eds), Advances in organic geochemistry 13, 263–272.

Jenkyns, H. C., 1999- Jenkyns, H.C., 1999. Mesozoic anoxic events and palaeoclimate. Zentralblatt fur Geologie und Paläontologie, Teil I, 1997, 943-949.

Jenkyns, H. C., Forster, A., Schouten, S. and Sinninghe-Damste, J. S., 2004- High temperatures in the Late Cretaceous Arctic Ocean. Nature 432, 888-892. DOI:10.1038/nature03143.

Keller, G., Adatte, T., Berner, Z., Chellai, E. H. and Stueben, 2008- Oceanic events and biotic effects of the Cenomanian-Turonian anoxic event,Tarfaya Basin, Morocco. Cretaceous Research 29, 976-994.DOI: 10.1016/j.cretres.2008.05.020.

Kessels, K., Mutterlose, J. and Ruffel, A., 2003- Calcareous nannofossils from late Jurassic sediments of the Volga Basin (Russian Platform): evidence for productivity-controlled black shale deposition. International Journal of Earth Sciences 92, 743-757. DOI: 10.1007/s00531-003-0343-x.

Kolonic, S., Sinninghe Damsté, J. S., Böttcher, M. E., Kuypers, M. M. M., Kuhnt, W., Beckmann, B., Scheeder, G. and Wagner, T., 2002- Geochemical characterization of Cenomanian/Turonian black shales from the Tarfaya Basin (SW Morocco), relationships between palaeoenvironmental conditions and early sulphurization of sedimentary organic matter. Journal of petroleum Geology 25, 325-350.

Kuypers, M. M. M., Pancost, R. D., NNijenhuis, I. A. and Sinnighe Damste, J. S., 2002- Enhanced productivity led to increased organic carbon burial in the euxinic North Atlantic basin during the late Cenomanian oceanic anoxic event. Paleoceanography 17, PA1051, DOI: 10.1029/2000PA000569.

Lamolda, M. A. and Gorostidi, A., 1996- Calcareous nannofossils at the Cenomanian–Turonian Boundary Event in the Ganuza section, Northern Spain. Memoir Geological Society of India 37, 251-265.

Lamolda, M. A., Gorostidi, A., Paul, C. R. C., 1994- Quantitative estimates of calcareous nannofossil changes across the Plenus Marls (latest Cenomanian), Dover, England: implications for the generation of the Cenomanian-Turonian Boundary Event. Cretaceous Research 15, 143-161.

Leary, P. N., Carson, G. A., Cooper, M. K. E., Hart, M. B., Horne, D., Jarvis, I., Rosenfeld, A. and Tocher, B. A., 1989- The biotic response to the late Cenomanian oceanic anoxic event; integrated evidence from Dover, SE England. Journal of the Geological Society, London 146, 311-317. DOI: 10.1144/gsjgs.146.2.031.

Leckie, R. M., Bralower, T. J. and Cashman, R., 2002- Oceanic anoxic events and plankton evolution: Biotic response to tectonic forcing during the mid-Cretaceous. Paleoceanography 17, 3, DOI:10.1029/2001PA000623.

Linnert, C. and Mutterlose, J., 2008- Kalkige Nannofossilien des Untercampans (Oberkreide) von Buldern. (Stadt Dümen; NRW). Geologie Paläontologie Westfalen 71, 77-101.

Linnert, C., Mutterlose, J. and Erbacher, J., 2010- Calcareous nannofossils of the Cenomanian/Turonian boundary interval from the Boreal Realm (Wunstorf, northwest Germany). Marine Micropaleontology 74, 38-58. DOI: 10.1016/j.marmicro.2009.12.002.

Linnert, C., Mutterlose, J. and Herrle, J. O., 2011a- Late Cretaceous (Cenomanian- Maastrichtian) calcareous nannofossils from Goban Spur (DSDP Sites 549, 551): Implications for the palaeoceanography of the proto North Atlantic. Palaeogeography, Palaeoclimatology, Palaeoecology 299, 507-528. DOI: 10.1016/j.palaeo.2010.12.001

Linnert, C., Mutterlose, J. and Mortimore, R., 2011b- Calcareous nannofossils from Eastbourne (Southeastern England) and the Paleoceanography of the Cenomanian-Turonian boundary interval. Palaios 26, 298-313. DOI: 10.2110/palo.2010.p10-130r.

Mahanipour, A., Mutterlose, J., Kani, A. and Adabi, M. H., 2011- Palaeoecology and biostratigraphy of early Cretaceous (Aptian) calcareous nannofossils and the d13Ccarb isotope record from NE Iran. Cretaceous Research 32, 331-356. DOI: 10.1016/j.cretres.2011.01.006.

Melinte-Dobrinescu, M. C. and Bojar, A. V., 2008- Biostratigraphic and isotopic record of the Cenomanian-Turonian deposits in the Ohaba-Ponor section (SW Haţeg, Romania). Cretaceous Research 29, 1024-1034. DOI: 10.1016/j.cretres.2008.05.018.

Miller, K. G., Wright, J. D. and Browning, J. V., 2005- Visions of ice sheets in a greenhouse world. Marine Geology 217, 215-231. DOI: 10.1016/j.margeo.2005.02.007.

Mort, H. P., Adatte, T., Keller, G., Bartels, D., Follmi, K. B., Steinmann, P., Berner, Z. and Chellai, E. H., 2008- Organiccarbon deposition and phosphorus accumulation during Oceanic Anoxic Event 2 in Tarfaya, Morocco. Cretaceous Res. 29, 1008–1023. DOI:10.1016/j.cretres.2008.05.026.

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

Mutterlose, J., 1989- Temperature controlled migration of calcareous nannofloras in the NW European Aptian, mCrux, J. A., and van Heck, S. E. (Eds.). Nannofossils and their applications. Ellis Horwood Limited, Chichester (England), pp.327-339.

Mutterlose, J., Bornemann, A. and Herrle, O., 2005- Mesozoic calcareous nannofossils – state of the art. Palaontologische Zeitschrift, 79/1, 113–133.

Paul, C. R. C., Lamolda, M. A., Mitchell, S. F., Vaziri, M. R., Gorostidi, A. and Marshall, J. D., 1999- The Cenomanian-Turonian boundary at Eastbourne (Sussex, UK): a proposed European reference section. Palaeogeography, Palaeoclimatology, Palaeoecology 150, 83–121. DOI: 10.1016/S0031-0182(99)00009-7.

Pedersen, T. F. and Calvert, S. E., 1990- Anoxia vs. productivity: What controls the formation of organic-carbon-rich sediments and sedimentary rocks? American Association of Petroleum Geologists Bulletin 74, 454-466.

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

Premoli Silva, I., Erba, E., Salvini, G., Locatelli, C. and Verga, D., 1999- Biotic changes in Cretaceous oceanic anoxic events of the Tethys. Journal of Foraminiferal Research 29, 352–370.

Roth, P. H. and Krumbach, K. R., 1986- Middle Cretaceous calcareous nannofossil biogeography and preservation in the Atlantic and Indian Oceans: implications for paleoceanography. Marine Micropaleontology 10, 235-266. DOI: 10.1016/0377-8398(86)90031-9.

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, pp. 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., et al. (Eds.), Initial Reports of the Deep Sea Drilling Project, vol. 76, pp. 587-621. DOI: 10.2973/dsdp.proc.76.125.1983.

Schlanger, S. O. and Jenkyns, H. C., 1976- Cretaceous Oceanic Anoxic Events: Causes and Consequences. Geologie en Mijnbouw 55 (3-4), 179-184. http://ora.ox.ac.uk/objects/uuid:0921605b-4793-43df-889d-7b896790de62.

Sinninghe Damsté, J. S., Bentum E. C., Reichart, G. J., Pross, J. and Schouten, S., 2010- A CO2 decrease-driven cooling and increased latitudinal temperature gradient during the mid-Cretaceous Oceanic Anoxic Event 2. Earth and Planetary Science Letters 293, 97–103. DOI: 10.1016/j.epsl.2010.02.027.

Snow, L. J., Duncan, R. A. and Bralower, T. J., 2005- Trace element abundances in the Rock Canyon Anticline, Pueblo, Colorado, marine sedimentary section and their relationship to carribean plateau construction and oxygen anoxic event 2. Paleoceanography 20,PA3005, 14 p. DOI:10.1029/2004PA001093.

Stein, R., 1991- Accumulation of Organic Carbon in Marine Sediments Results from the Deep Sea Drilling Project/Ocean Drilling Program (DSDP/ODP). Springer-Verlag Berlin Heidelberg. DOI: 10.1007/BFb0010382.

Tiraboschi, D., Erba, E. and Jenkyns, H. J., 2009- Origin of rhythmic Albian black shales (Piobbico core, central Italy): Calcareous nannofossil quantitative and statistical analyses and paleoceanographic reconstructions, Paleoceanography 24, PA2222, DOI: 10.1029/2008PA001670.

Turgeon, S. C. and Creaser, R. A., 2008- Cretaceous oceanic anoxic event 2 triggered by massive magmatic episode. Nature 454, 323-326. DOI :10.1038/nature07076.

Tyson, R. V., 1995- Sedimentary organic matter: organic facies and palynofacies. Chapman & Hall, Science. 615 pp.

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

Voigt, S., Aurag, A., Leis, F. and Kaplan, U., 2007- Late Cenomanian to Middle Turonian high- resolution carbon isotope stratigraphy: New data from the Münsterland. Cretaceous Basin, Germany. Earth an Planetary Science Letters 253, 196-210. DOI: 10.1016/j.epsl.2006.10.026.

Voigt, S., Erbacher, J., Mutterlose, J., Weiss, W., Westerhold, T., Wiese, F., Wilmsen, M. and Wonik, T., 2008- The Cenomanian-Turonian of the Wunstorf section (North Germany): global stratigraphic reference section and new orbital time scale for Oceanic Anoxic Event 2. Newsletters on Stratigraphy 43 (1), 65-89. DOI: 10.1127/0078-0421/2008/0043-0065.

Voigt, S., Gale, A. S. and Flogel, S., 2004- Midlatitude shelf seas in the Cenomanian-Turonian greenhouse world: Temperature evolution and North Atlantic circulation. Paeoceanography 19, PA4020, DOI:10. 1029/2004PA001015.

Watkins, D. K., 1989- Nannoplankton productivity fluctuations and rhythmically-bedded pelagic carbonates of the Greenhorn Limestone (upper Cretaceous). Palaeogeography, Palaeoclimatology, Palaeoecology 74, 75-86. DOI: 10.1016/0031-0182(89)90020-5.

Williams, J. R. and Bralower, T. J., 1995- Nannofossil assemblages, fine fraction stable isotopes, and the paleoceanography of the Valanginian-Barremian (Early Cretaceous) North Sea Basin. Paleoceanography 10 (4), 815-839. DOI. 10.1029/95PA00977.