The latest Cretaceous-Early Tertiary Ulukisla Basin, S. Turkey : sedimentation and tectonics of an evolving Tethyan suture zone

• Main Author: Clark, Matthew
• Published: University of Edinburgh 2002
• Subjects: 551.7
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.643199

The Upper Cretaceous (Maastrichtian) to Upper Eocene Ulukisla Basin in representative of the sedimentary and tectonic evolution of extensive Early Tertiary basins in central Anatolia, including the Tuzgölü and Sarkisla Basins. These basins lie along the proposed Inner Tauride Ocean suture zone between two microcontinental units in central Anatolia (Turkey), the Tauride Block and Nigde-Kirsehir Massif. Investigation of the Ulukisla Basin shed light on processes of microcontinental collision and ocean basin suturing of Neo-Tethys, which hopefully, will be applicable to other zones of continental collision (e.g. central Tibet). The Ulukisla Basin overlies a Late Cretaceous ophiolitic mélange located between the Bolkar Carbonate Platform to the south and the Nigde-Kirsehir metamorphic massif to the north. The basin stratigraphy records successive phases of transgression, subsidence, volcanism, evaporite deposition, deformation and uplift. The nature of these events can be interpreted by assessment of the lithostratigraphy in terms of sedimentary facies, biostratigraphy, structural geology and volcanic geochemistry. Further characterisation of the basin-history was achieved by analysis of sedimentary structures, construction of subsidence curves and provenance studies. Transgression in the Ulukisla Basin, during the Maastrichtian, followed by large-scale subsidence, is evidenced by shallow-marine sedimentation and subsequent deposition of unstable slope facies and turbidites. The basin succession includes c. 2 km of Upper Palaeocene-Lower Eocene basaltic to andesitic submarine pillow lavas, lava flows, volcaniclastics and intercalated limestones. Whole-rock XRF chemical analysis indicates a within plate-origin, with a marked subduction influence (e.g. relative Nb depletion). Uplift and closure of the basin are recorded by evaporite deposition, widespread compressional deformation and a regional unconformity. The subsidence curves are consistent with an extensional (or trans-tensional) basin terminated by uplift.