Middle-Late Eocene marine record of the Biga Peninsula, NW Anatolia, Turkey

• Published in: Geologica acta Vol. 16; no. 2; p. 163
• Main Authors: Ozcan, E, Okay, A.I, Burkan, K.A, Yucel, A.O, Ozcan, Z
• Format: Journal Article
• Language: English
• Published: Geologica Acta 01-06-2018; Universitat de Barcelona (UB), Geociències Barcelona (Geo3BCN), Institut de Diagnosi Ambiental i Estudis de l'Aigua (IDAEA), Universitat Autònoma de Barcelona (UAB)
• Subjects: Aquatic ecological zones; Biga Peninsula; Biostratigraphy; Carbonates; Eocene; Larger Benthic Foraminifera (LBF); Metamorphic rocks; Relative dating (Chronology); Stratigraphy
• ISSN: 1695-6133; 1696-5728
• DOI: 10.1344/GeologicaActa2018.16.2.4

The Eocene shallow marine deposits marking the first marine incursion in the Biga Peninsula (NW Turkey) after the collision of the Sakarya and Anatolide-Tauride plates were investigated based on paleontological, litho- and chrono-stratigraphic data. Larger Benthic Foraminifera (LBF) from patchily distributed outcrops were studied in order to i) revise the stratigraphy of Eocene shallow marine units, and ii) establish a modern biostratigraphic setting and a correlation scheme. The Sevketiye Formation (Fm.) is herein defined as a predominantly shallow marine clastic deposit with subordinate carbonates overlying the Samlica metamorphic rocks, and passing laterally to the Sogucak Fm., a carbonate unit that is widely represented in the Thrace Basin. The record of alveolinids, primitive developmental stages of heterosteginids, and orthophragminids in the Sevketiye Fm. suggests that this formation is part of the Shallow Benthic Zones (SBZ) 16c/17 (Late Lutetianc/Early Bartonian), SBZ17c/18 and SBZ19A (Early Bartonian/earliest Priabonian). The Sogucak Fm., which overlies the Eocene volcanics, on the other hand, yielded advanced developmental stages of heterosteginids, Spiroclypeus sp. and Nummulites fabianii lineages, implying a younger marine incursion during the Late Eocene (earliest Priabonian; SBZ19A). A drastic shift in the depositional regime is marked amid Priabonian by the deposition of deep-marine clastics and volcanoclastics of the Ceylan Fm. In conclusion, the Eocene Sea transgressed first Gokgeada (in the Aegean Sea) during the Late Lutetian, then reached the Biga and Gelibolu peninsulas in the Bartonian, and finally led to the widespread deposition of carbonate and siliciclastic rocks in the Biga Peninsula and the Thrace Basin during the Late Bartonian and Priabonian. KEYWORDS Larger Benthic Foraminifera (LBF). Stratigraphy. Biostratigraphy. Biga Peninsula. Eocene.