Geology of the Sivas-Erzincan Tertiary Basin

Abstract

The Tertiary basin situated between Sivas and Erzincan in Eastern Anatolia display complex sedimentary and tectonic features. Munzur limestones lie to the south of the basin whereas, in the northwest lies the Karaçayır formation. Intrusion of the Refahiye ophiolitic complex took place between Lower Campanian-Lower Maastrichtian and are overlain unconformably by Upper Maastrichtian aged neritic carbonate sediments. These carbonates conformably pass into Paleocene- Eocene aged deep-sea sediments with olistostromal flysch characteristics. Oligo-Miocene and Lower-Middle Miocene aged elastics and carbonates unconformably cover the older units. Afore said elastics and carbonates were deposited in marine, lagunar and continental environmental conditions and the environs in the region are transitional laterally and vertically with each other. Upper Miocene aged evaporitic elastics unconformably cover the lower units. Plio-Quatemary is represented by continental deposits. Lateral movement of the Refahiye ophiolitic complex intruded in the region between Lower Campanian-Lower Maastrichtian took place intermittently and repeated few times with interruptions. As a result of lateral movement (transfer) of the Refahiye ophiolitic complex, a large pan of the Eocene aged Gülandere formation was thrusted over itself in north-south direction and pan of it was enclosed by the ophiolitic complex lower beds were thrusted over the Oligo- Miocene and Lower-Middle Miocene aged units, thus forming overturned folds with East-West strike. During Neotectonic period strike-slip faults of Tecer and Düzyayla were formed.