STRUCTURAL ARCHITECTURE AND TECTONIC EVOLUTION OF THE LATEST MESOZOIC AND CENOZOIC ULUKISLA SUCCESSOR BASIN IN SOUTH-CENTRAL TURKEY

The E-W-trending Ulukisla basin in south-central Turkey occurs between the Central Anatolian Crystalline Complex (CACC) to the north and the Tauride carbonate platform (TCP) to the south. It contains 2 to 5 km-thick, uppermost Cretaceous to Miocene-Pleistocene strata intercalated with Eocene volcanic and intrusive rocks. The uppermost Cretaceous through Eocene sedimentary rocks consist mainly of an upward shallowing sequence of clastic units (sandstone, siltstone & shale). The Eocene sequence starts with deep marine turbidites and is transitional upwards into continental Oligocene sandstone, shale and lignites. There is an upward transition from Lower Oligocene shallow marine, deltaic deposits to Upper Oligocene-Miocene evaporite and terrestrial deposits, indicating a complete stratigraphic record of a successor basin. The Eocene and Oligocene strata in the southern part of the basin display north-vergent thrust faults and folds that accommodated collision-induced shortening, whereas those in the central and northern parts show extensional normal faults. Extensional deformation in the UB strata was coeval with the extrusion of basaltic, andesitic and trachytic volcanics and the emplacement of monzonitic stocks, dikes and plutons. We interpret the Eocene magmatism and associated extensional deformation in the UB to have resulted from slab breakoff. The Ulukisla depocenter initially developed as a post-collisional relict basin between the CACC and TCP in the latest Mesozoic-early Cenozoic and then evolved into a terrestrial basin in the late Tertiary. Thus, the UB developed first via thrust loading and then by tectonic subsidence. The basin geometry, sediment sources, and regional tectonic controls on basin formation hence changed with time.