Abstract.

"The early Toarcian of the Early Jurassic saw a long-term positive carbon-isotope excursion (CIE) abruptly interrupted by a significant negative excursion (nCIE), associated with rapid global warming and an oceanic anoxic event (T-OAE, ∼183 Ma). However, the detailed processes and mechanisms behind widespread ocean deoxygenation are unclear. Here, we present high-resolution carbonate-associated sulfate sulfur-isotope [...]".

Source: Science Direct
Authors: Zhong Han et al.
DOI: https://doi.org/10.1016/j.epsl.2023.118404

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Abstract.

"This study provides a detailed examination of a condensed Cenomanian-Turonian (C-T) succession of two sections (Dokan Dam and Khalakan) in the Kurdistan Region, Northeastern Iraq, based on biostratigraphy (calcareous nannofossils and planktic foraminifera), carbon and oxygen isotope geochemistry, and facies analysis. The C/T boundary in this region is characterized by a hiatus noticeable due to the absence of the Globigerinelloides benthonensis and Dicarinella hagni subzones and the lack of positive carbon isotope excursion (CIE) peak b during the Oceanic Anoxic Event 2 (OAE2). [...]".

Source: Science Direct
Authors: Fadhil A. Lawa et al.
DOI: https://doi.org/10.1016/j.jafrearsci.2023.105064

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Abstract.

"Oceanic anoxic events (OAEs) represent discrete intervals of decreased marine oxygen concentrations often associated with volcanism, enhanced organic carbon burial coupled with positive δ13C excursions, and significant biotic turnover. Cretaceous OAE 2 (ca. 94 Mya) is especially notable for globally-distributed changes in calcareous invertebrate and plankton populations. While the presence of organic-rich facies is consistent with locally anoxic environments in many cases, determining the global extent of anoxia is more problematic. [...]".

Source: Science Direct
Authors: Joseph T. Kulenguski et al.
DOI: https://doi.org/10.1016/j.palaeo.2023.111756

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Full title: "Paleoenvironmental significance of the carbon isotope record across the Cenomanian–Turonian transition and the Oceanic Anoxic Event 2 (OAE2) in the southeastern Neotethys, Zagros, Iran"

Abstract.

"A high–resolution carbon isotope record of pelagic carbonates (δ13Ccarb) from the Zagros Mountains, Iran, documents a 1.8‰ positive carbon isotope excursion (CIE) in the southeastern Neotethys during the Cenomanian–Turonian transition, corresponding to Ocean Anoxic Event (OAE2). The succession is controlled by biostratigraphy that includes the Rotalipora cushmani [...]".

Source: Science Direct
Authors: Borhan Bagherpour et al.
DOI: https://doi.org/10.1016/j.cretres.2023.105574

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Abstract.

"Sea-level changes exert an important control on oceanic circulation and climate evolution. Researchers have proposed that sea-level rise favored accumulation of sediments enriched in organic carbon during oceanic anoxic events (OAEs), although high-frequency sea-level changes and their controlling mechanism have remained poorly constrained. Here we present a detailed sedimentological and geochemical study on Aptian (Lower Cretaceous) shallow-water carbonates of the Dariyan Formation exposed in the Zagros fold belt of southern Iran. [...]".

Source: Science Direct
Authors: Yiwei Xu et al.
DOI: https://doi.org/10.1016/j.gloplacha.2023.104236

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Abstract.

"The Cretaceous Oceanic Anoxic Event 2 (OAE2) is a greenhouse episode of severe marine anoxia at the Cenomanian-Turonian boundary. This time interval is characterized by rising sea surface temperature, enhanced marine biological productivity, and widespread occurrence of organic-rich black shales. With an export of biological production to the deep ocean, organisms consume vast amounts of oxygen and subsequently utilize nitrate and sulfate as electron acceptors in organic matter degradation, thereby affecting biogeochemical cycles of nitrogen and sulfur. [...]".

Source: Science Direct
Authors: Ruixiang Zhai et al.
DOI: https://doi.org/10.1016/j.gloplacha.2023.104182

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Abstract.

"At Site U1516 (Mentelle Basin, southeast Indian Ocean, offshore western Australia), the International Ocean Discovery Program (IODP) Expedition 369 recovered an almost complete pelagic record of the Upper Cretaceous, including the Oceanic Anoxic Event 2 (OAE 2). To better understand paleoenvironmental changes across OAE 2, 32 samples were analysed for benthic foraminiferal abundance data that represent one of the few benthic foraminiferal datasets spanning the OAE 2 in the southern high latitudes. [...]".

Source: Science Direct
Authors: Erik Wolfgring et al.
DOI: https://doi.org/10.1016/j.cretres.2023.105555

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Abstract.

"This paper reviews global records of anoxic events of the Middle Devonian – earliest Mississippian, as well as the possible triggers and controls of these events. These “anoxic events” are complex multistage paleoenvironmental disturbances manifested in multiple proxies, which we showcase with the Horn River Group (HRG) – a succession of basinal organic-rich shales and cherts deposited during the latest Eifelian – earliest Late Frasnian(∼386–373 My ago) on the western continental margin of Laurentia near the paleo-equator. [...]".

Source: Science Direct
Authors: Pavel Kabanov et al.
DOI: https://doi.org/10.1016/j.earscirev.2023.104415

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Abstract. 

"Oceanic Anoxic Events (OAEs) are important geological events that may be analogues to future climate-driven deoxygenation of our oceans. Much of the global ocean experienced anoxic conditions during the Cenomanian–Turonian OAE (OAE2; ∼94 Ma), whereas the Western Interior Seaway (WIS) experienced oxygenation at this time. Here, organic geochemical and palynological data generated from Cenomanian–Turonian age sediments from five sites in the WIS are used to investigate changing redox and ecological conditions across differing palaeoenvironments and palaeolatitudes. [...]".

Source: Science Direct
Authors: Libby J. Robinson et al.
DOI: https://doi.org/10.1016/j.palaeo.2023.111496

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Abstract. 

"Oceanic anoxic events (OAEs) are considered as periods of oxygen deficiency in many oceans; accompanied by accumulation of organic-rich black shales. Mesozoic anoxic events were recognized based on the presence of black shales that are rich in organic matter. The most significant anoxic events during the Mesozoic are the Early Toarcian, the Early Aptian, and the Cenomanian–Turonian. The less significant events are the Valanginian-Hauterivian, the Hauterivian-Barremian, the Aptian-Albian, the Late Albian, the Albian-Cenomanian, and the Coniacian-Santonian. [...]".

Source: Springer Nature
Authors: Tarek Anan & Adam El-Shahat 
DOI: https://doi.org/10.1007/978-3-030-95637-0_7

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