STRATIGRAPHY OF THE TECTONOSTRATIGRAPHIC UNITS AROUND HADIM-BOZKIR-TAŞKENT REGION (NORTHERN PART OF THE CENTRAL TAURIDES, TURKEY)

Abstract

The region studied shows the typical geological features of the Central Taurides and includes several tectonic units with distinctive stratigraphic, structural and metamorphic feature. These units are from base upward the Geyik Dağı, Aladağ, Bolkar dağı and Bozkır units. The Geyik Dağı Unit, which lies tectonically at the base of all the other units, and hence forms relative autochthonous, is constituted of Lower Paleozoc carbonate and clastic rocks, Upper Mesozoic-Lower Tertiary shelf type carbonate and an olistostromal flysch of Lutetian age. The Aladağ and Bolkar Dağı units comprise Upper Devonian-Upper Cretaceous carbonates and clastic rocks and Senonian olistostromal flysch. Although these two units have some apparent similarities, they also exhibit distinct differences in the stratigraphy, lithology and depositional environment. Both the Aladağ and Bolkar Dağı units form flat-lying nappes over the Lutetian flysch of the Geyik Dağı unit. The Bozkır Unit is a large-melange constituted of blocks and slices of TriassicCretaceous basinal, continental margin and minor platform deposits, basic submarine volcanic rocks, diabase, serpentinite etc. It includes blocks of a single lithology as large tectonic slices made up of several rock-stratigraphic units reflecting basinal deposition over an extensive period. It is believed that during the Late Maastrichtian- Illerdian (Late Paleocene-Early Eocene) a narrow oceanic basin, represented by the Dipsiz G6I Ophiolitic Melange of ophiolite cherty pelagic limestone with basic volcanic intercalations and calsiturbidites, existed between the Geyik dağı and Aladağ units. Dipsiz G6I Ophiolitic Melange occurs as tectonic slices of various thicknesses above the chaotic Lutetian flysch of the Geyik dağı unit and above the allochthonous Aladağ and Bolkar dağı units. A palinspastic reconstruction for the Early Triassic-Senonian period, based on the tectonic and stratigraphic relations between the different units, would place the Geyik dağı Unit in the south and Aladağ, Bolkar Dağı and Bozkır units gradually northward. Such a reconstruction would range from a platform in the south to an oceanic basin in the north. Following the closure of this oceanic basin during the Late Senonian, which may be called as the North Tethyan Ocean, the Bozkır Unit internally sliced and was emplaced over the Bolkar Dağı units was closed during the Lutetian. Following this closure, the Bolkar Dağı and Aladağ units with their tectonic cover of the Bozkır unit were emplaced over the Geyik Dağı unit.