Benthonic foraminiferal assemblages and microfacies analysis of Paleocene-Eocene carbonate rocks in the Kastamonu region, Northern Turkey

摘要

The Kastamonu region, NW Turkey, is known for its rich foraminiferal marine biota and variety of deposits from Paleocene to Eocene times. The focus of this study is on the foraminiferal assemblages and microfacies analysis of the sediments. Usually Paleocene shallow water limestones overlie Maastrichtian rocks conformably. They are characterized by benthic foraminifera such as Laffitteina mengaudi (Astre) Anomalina sp., Eponides sp., Rotalia sp., Mississippina sp., Haurenidae in the lower strata and numerous rotaliid such as Pseudocuvillierina sireli Inan, Rotalia perovalis Terquem, R. trochidiformis (Lamarck), Kathina selveri Smout, Kathina major Smout, Smoutina? subspherica (Sirel), Miscellanea primitiva Rahaghi in the upper strata. The Eocene clayey limestones, limestones and marls, which generally conformably overlie the Paleocene, are commonly characterized by benthic foraminifera of Orbitolites complanatus Lamarck, Asterigerina rotula (Kaufmann), Gyroidinella magna (Le Calvez), Fabiania cassis (Oppenheim), Nummulites minervensis Schaub, Nummulites burdigalensis de la Harpe, Nummulites millecaput Boubee, Assilina placentula (Deshayes), Assilina exponens (Sowerby). Microfacies analyses of the Paleocene-Eocene carbonate rocks were carried out with respect to the distribution of depositional components and biota. The Danian, Selandian and Thanetian units are characterized by reefal (organic buildup), shelf lagoon, shelf and tidal flat paleoenvironments. The Ilerdian units are represented by reefal and shelf lagoon environments, while the Cuisian units are characterized by shelf lagoon and deep shelf settings. The Lutetian units indicate platform margin through fore-slope to deep marine shelf paleoenvironments.