Türkiye Jeoloji Bülteni

The importance of Block Movements İn Structural Evolution of the Northern Part of Central Taurus

Abstract: The area discussed lies in the northern part of the central TaurusMountains, which form part of the Taurus orogenic belt. It contains thesurroundings of Hadim ,and Bozkır cities. The lithological units of Paleozoic ,and younger ages, deposited in different basins, are now in faultedcontact. The Hadim ,and Geyikdağı units are autochthonous, while theSouth Central Anatolia ,and the Central Taurus units are allochthonous.Evidence shows that the allochthonous South Central Anatolia Unit camefrom south central Anatolia. This unit has great litological affinity to themetamorphic Paleozoic rock which occur widespread to the north of thearea discussed, in south central Anatolia. Further, folds in the underiyingautochthonous Hadim Unit, which is in fault contact with the overlingSouth Central Anatolia Unit, suggest again transport of the latter unit. Theauthor proposes that the allochthonous Central Taurus Unit -named byBlumenthal the «Hadim nappe» / «Palaezoic of Hadim» - is as a wholenot a nappe but has moved both in northerly ,and southerly direction. Thepresence of the folds ,and reverse faults which have developed near thefault contacts ,and the stratigraphic correlation with nearby stratigraphieunits both to the south ,and north substantiate this proposal. The HadimUnit which aiso includes Cambrian ,and Ordovician sediments was deposited in a basin flanked by the afore mentioned allochthonous units.The Geyikdağı autochthonous unit which lies to the south of the CentralTaurus Unit does not fall within the framework of this paper. All units arecut by thrust faults dipping NE. Both the transport of the allochthonousunits ,and the development of thrust faults occurred within post-Lutetian ,and pre-Miocene time interval. The transport of the allochthonous Central Taurus Unit took place after the transport of the South Central Anatolia Unit; but evidence for different times of transport of different units hasnot been found. At least since the Upper Devonian vertical block movements were dominant in the structural evolution. The disconformities between different lithological units are mostly not angular in character, ,andrepresent thus evidence for vertical novement. It is proposed that verticalblock movements produced gravitational spreading ,and are the cause ofthe lateral shifts of the allochthonous units. This proposal depends on theabsence of big folds with horizontal axial planes, on the absence of overturning both in the South Central Anatolia Unit which travelled a longdistance ,and in Central Taurus Unit which shows movements both to thesouth ,and to the north, ,and on the position of the big thrust fault bounding the Central Taurus Unit to the north.