Cenomanian–Turonian drowning of the Arabian Carbonate Platform, the İnişdere section, Adıyaman, SE Turkey

Abstract

The Cenomanian–Turonian carbonate ramp in the Adıyaman Region of SE Turkey (Northern Arabian Platform) records an abrupt shift from benthic carbonate deposits to pelagic deposits near the Cenomanian–Turonian boundary event (CTBE) in the İnişdere stratigraphic section and surrounding borehole sections. A positive δ13C excursion of up to 2.15% is recorded in carbonate and organic carbon deposited around the CTBE and provides evidence of a direct link between the CTBE and oceanic anoxic events and the demise of the shallow carbonate production in the Derdere Formation. The microfacies analyses, biostratigraphic dating and palaeoenvironmental interpretations suggest that the platform was drowned near the CTBE as a result of changing environmental conditions. The microfacies indicating significant deepening show a contemporaneity to equivalent surfaces globally and thus strongly support an isochronous formation of Cenomanian–Turonian facies by eustatic sea-level changes. Anoxia spreading over the platform drastically reduced the carbonate production as observed in the studied sections and, therefore, resulted in a reduction in carbonate accumulation rates. Regional/local subsidence and a coeval sea-level rise during the late Cenomanian to early Turonian interval were the cause of the drowning of the platform, including regional anoxia at the northern Arabian platform linked to the Cenomanian–Turonian oceanic anoxic event (OAE2).

Micropalaeontology, biostratigraphy, and depositional setting of the mid-Cretaceous Derdere Formation at Derik, Mardin, south-eastern Turkey

“…Here, the authors were able to demonstrate that, at this locality at least, the base of the Karababa Formation corresponds to the Cenomanian-Turonian Boundary Event, where anoxia and sea level rise contribute to the demise of the Derdere carbonate platform. Carbon isotope stratigraphy at Türkoglu (Mülayim et al, 2019b) supports this notion. In the Karababa Formation, constraint is provided by planktonic foraminifera, calcareous nannofossils, and carbon isotope data and demonstrates that despite a number of suggestions in the literature that the Derdere Formation extends into the Turonian (see paragraphs above), this is in fact unlikely.…”

“…The lower part of the formation is organic carbon-rich (Demirel and Guneri, 2000;Demirel et al, 2001), deposited in relatively deep water, and passes up into a shallowing-upwards sequence of lagoonal and tidal-flat carbonates (Çelikdemir et al, 1991). Mülayim et al (2019b) considered the Derdere Formation at Türkoglu (also some distance to the north-west of Derik) to be as old as early Cenomanian based on the presence (not illustrated) of Ovalveolina maccagnoae De Castro.…”

Sequence Stratigraphy, Palaeogeography and Petroleum Plays of the Cenomanian – Turonian Succession of the Arabian Plate: An Updated Synthesis

“…In southeast Turkey, the Karababa-A Member spans the Turonian based on biostratigraphy and carbon isotopes (Mülayim et al, 2020). The Karababa-A Member is an organic-rich carbonate with average TOC of 1.4 wt.% (Demirel and Guneri, 2000) and was deposited within an intrashelf basin or restricted lagoon environment (Çelikdemir et al, 1991) (see Fig.…”

Two types of hyperthermal events in the Mesozoic-Cenozoic: Environmental impacts, biotic effects, and driving mechanisms

“…For the OAE1a, the demise of carbonate platforms was accompanied by the occurrence of a condensed interval and hardgrounds in the northern Tethys margin (Skelton and Gili, 2012), whereas deposition continued and strata rich in Lithocodium-Bacinella and or orbitolinid are deposited in the southern Tethys margin (Husinec et al, 2012). For OAE2, the demise of carbonate platforms only occurred in the Pyrenees area, northern Spain (Drzewiecki and Simo, 1997), western Croatia (Korbar et al, 2012) and southeastern Turkey (Mülayim et al, 2019).…”