Timing of depositional regime changes during the Late Cretaceous evolution of the Southern Pontides (Ankara, Central Anatolia, Turkey)

During the Cretaceous, vast amounts of marine sediments were deposited along the south-facing active margin of the Eurasia. A stratigraphic section of 91 m was analyzed for planktonic foraminifera (75 samples), with the aim of establishing a refined biostratigraphy of Cenomanian-Campanian deposits in Central Anatolia. A biostratigraphic framework comprising nine biozones was established. In ascending order, the Rotalipora cushmani, Whiteinella archaeocretacea and Helvetoglobotruncana helvetica zones were defined in the uppermost Cenomanian-Turonian interval. The lack of Coniacian index markers suggests the existence of a hiatus for this interval. In the upper part of the section, the Dicarinella asymetrica, Globotruncanita elevata, Contusotruncana plummerae, Globotruncanella havanensis and Globotruncana aegyptiaca zones were identified for the Santonian and Campanian deposits. The presence of Gansserina gansseri, Globotruncanita angulata, G. conica and G. pettersi in the uppermost part of the section shows that the section ends at the base of the Gansserina gansseri Zone, indicating uppermost Campanian. The planktonic foraminifera biozonation framework provides strong evidence for the timing of the depositional history of the active continental margin that developed south of the Pontides. These phases are mainly the formation of olistostromes of pre-Santonian age, following condensed carbonate deposition during the Santonian and finally the switch from forearc deposition to the formation of a thick sequence of siliciclastic succession starting in the Campanian.


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During Late Jurassic-Early Cretaceous the Pontides were the site of a wide carbonate platform facing the Tethys ocean in the south. In the western Pontides the Upper Jurassic-Lower Cretaceous shallow marine carbonates abut the Tethyan Izmir-Ankara suture with no evidence for platform margin deposits. The Sivrihisar klippe 50 km south of the Izmir-Ankara suture preserves a record of the missing platform margin. In the Upper Jurassic-Lower Cretaceous carbonates exposed in this Sivrihisar klippe, two coeval bu...
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Ninety-one percent of calcareous foraminiferal genera became extinct during the end-Permian mass extinction. The Early Triassic Epoch was a survival phase characterized by a short-lived proliferation of disaster forms and then I prolonged interval of low diversity. The orders Miliolida and Lagenida experienced limited taxonomic re-diversification in Early and Late Anisian time, respectively. All fusulinoidean fusulinides became extinct in Late Permian time, and only two non-fusulinoidean genera persisted in...
End-Permian mass extinction of lagenide foraminifers in the Southern Alps (Northern Italy)
Groves, John R.; Rettori, Roberto; Payne, Jonathan L.; Boyce, Matthew D.; Altıner, Demir (Cambridge University Press (CUP), 2007-05-01)
The Permian-Triassic boundary, examined at two sections in the Southern Alps, occurs similar to 1.0 to 1.5 m above the base of the Tesero Oolite Member of the Werfen Formation in a depositionally continuous sequence of inner neritic carbonates. Lagenide foraminifers from the boundary interval comprise 27 species in 15 genera plus additional unidentified taxa, most of which became extinct during the end-Permian crisis. The only survivors were "Nodosaria" elabugae and unidentified species in Geillitzina and N...
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The sedimentology and cyclic stratigraphy of palaeokarst structures in Aptian peritidal carbonate successions are interpreted using field and laboratory microfacies analyses of closely spaced samples from measured outcrop stratigraphic sections in southwest Turkey. Cycles displaying shallowing-upward metre-scale cyclicity are generally composed of lime mudstones/wackestones/packestones at the bottom and stromatolites or lime mudstones with charophytes and ostracods at the top. Subaerial exposure structures ...
Quantitative analysis of planktonic foraminifera across the Cretaceous-Paleogene transition and observations on the extinction horizon, Haymana Basin, Turkey
Karabeyoğlu, Uygar; Altıner, Sevinç; Altıner, Demir (Elsevier BV, 2019-12-01)
The Haymana Basin, Turkey, hosts complete record of sedimentation across the Cretaceous-Paleogene (K-Pg) boundary. To examine the K-Pg boundary transition and delineate the bioevents, two consecutive sections (UH and UKHB) were measured and sampled at high resolution. Three biozones were established: Plummerita hantkeninoides, P0 and P alpha. A detailed quantitative study on planktonic foraminifera was carried out for the P. hantkeninoides and the P0 zones for 63 150 mu m and >150 mu m size fractions. Resul...
Citation Formats
N. Sariaslan, S. Altıner, and D. Altıner, “Timing of depositional regime changes during the Late Cretaceous evolution of the Southern Pontides (Ankara, Central Anatolia, Turkey),” CRETACEOUS RESEARCH, pp. 0–0, 2020, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/40919.