Palaeoenvironment reconstruction and planktonic foraminiferal assemblages of Campanian (Cretaceous) carbonate succession, Cayrba area (Trabzon, NE Turkey)


Turk-Oz E., Ozyurt M.

CARBONATES AND EVAPORITES, cilt.34, ss.419-431, 2019 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 34 Konu: 2
  • Basım Tarihi: 2019
  • Doi Numarası: 10.1007/s13146-017-0413-y
  • Dergi Adı: CARBONATES AND EVAPORITES
  • Sayfa Sayıları: ss.419-431

Özet

The Campanian (Cretaceous) carbonate succession, which belongs to the uppermost part of the Mesozoic sequence in the Eastern Pontides (NE Turkey), is mainly composed of Globotruncana-bearing grey and red pelagic limestones. One of the most typical outcrops of the succession is located in the Cayrbaarea (NE Turkey) and it was studied with a combined sedimentological and palaeontological approach. Three microfacies types were identified and interpreted based on petrographic analysis of the depositional textures and fauna. They are (1) allochthonous bioclastic-calcispheral packstone/wackestone microfacies (MF-1), (2) calcispheral packstone/wackestone microfacies (MF-2), and (3) pelagic foraminiferal mudstone/wackestone microfacies (MF-3). These microfacies types correspond to slope, deep self and basin environments, respectively. Based on the planktonic foraminiferal assemblages, including Globotruncana cf. arca (Cushman), Globotruncana arca (Cushman), Globotruncana sp., Whiteinella sp., Archaeoglobigerina sp., Archaeoglobigerina blowi (Pessagno), Globotruncana lineiana (d'Orbigny), Whiteinella sp., Archaeoglobigerina cretacea (d'Orbigny), the age of the pelagic carbonate succession is Campanian. Microfacies and palaeontological characteristics of the studied section suggest that they were deposited in a slope to basin environment. The progressive deepening of the environment is probably caused by the vertical movement of the syn-sedimentary extensional tectonic regime. Moreover, a carbonate platform environment adjacent to the deep-marine environment is inferred to exist during the earliest Campanian because of the presence of rare allochthonous neritic skeletal components in the lower part of the section.