Türkiye Jeoloji Bülteni

An Example for the for Eland-Inter Montane Basin Development at the Eastern Tauride Carbonate Platform: Akdere Basin, Gurun-SW Sivas (Turkey)

Abstract: The area is Located at the northeastren section of the Eastern Taurus Mountains which is a part of theAnatolide-Toride platform. The Akdere basin presented in this paper is a typical example of a foreland-intermontanebasin. In general, foreland basins, resulting from the downward warping of the crust overlain by huge allochthonousunits (nappes) are of compressional in origin.The Akdere basin is surrounded by allochthonous units at its northern and southern margins. Thus, it differs fromthe similar compressional basins.Major unit exposed in the Akdere basin is the Middle Jurassic-Tertiary Geyikdağı rock assemblage. It consists offour lithostraüğraphic units, namely the Yüceyurt, Yanıktepe, Akdere and Demiroluk formations, The Yüceyurt formation (Middle Jurassic-Cenomanian) consists of platform facies such as dolomite, dolomitic limestone, foraminifer-algaepellet-intraclast-bearing mudstone and wackestones, The Yanıktepe formation is composed of rudist boundstonepackstone facies (Santonian-Campanian). The Akdere formation (Campanian-Paleocene-Lower Eocene) is composed ofsemi-pelagic facies, some carbonate fan deposit such as microbreccias turbidite of pelagic nature, pebble-bearing mudstones, calcarenite and channel cast conglomerate/breccia are also observed. The Demiroluk formation of Middle Eocene(Lutetian) age is composed of polygenic conglomerate/breccia, pebble bearing sandstones and marls. Facies changes inthe platform carbonates were resulted from lilting. In the same way, the fan deposits in the basin were accumulated under the control of a synsedimentary fault.The Akdere basin was formed an four stages. These are Middle Jurassic-Cenomanian stable platform stage, Turonian - Late Santonian flexural uplift and erosion, Late Santonian-Paleocene dismemberment of platform and formation ofa foreland-intermontane basin, and finally, Early Eocene deepening of the Akdere basin.