Geological Features and Lithostratigraphy of Eocene-Oligocene Magmatic Rocks in the Dededağ Area-Biga Peninsula, NW Turkey

In NW Anatolia, Eocene-Oligocene post-collisional magmatism continued over long intervals. In this study, the aim is to reveal the lithostratigraphic position and geochemical characteristics of volcanic rocks outcropping southeast of Lapseki (Çanakkale) in NW Anatolia. The magmatic rocks that comprise the topic of this study can be classified lithostratigraphically into 6 different units in the region. In the Eocene period, there are calc-alkaline Laledağ granodiorite and Beyçayır volcanic rocks with andesite and dacite composition and intermediate character, and also Kızıldam volcanic rocks with alkaline and basic character (basaltic trachyandesite, trachybasalt). Furthermore, in the Oligocene period, calc-alkaline volcanism starting with Dededağ volcanics, which have dacite and rhyolite composition and acidic-intermediate character, continued with the Kırcalar volcanics consisting of basalt and basaltic andesite, and the Harmancık volcanics ranging from basalt to rhyolite. The Çamyayla Pluton intruded into Oligocene volcanic rocks in the region. In this study, the geochemical data proved that magmatic units have alkaline and calc-alkaline character in the Eocene-Oligocene period. Alkaline lavas in the region are classified as high K and shoshonitic and calc-alkaline lavas are medium-high-K.