Türkiye Jeoloji Bülteni

Geology and Structural Evolution of the Divriği-Sivas Region

Abstract: The investigated area is situated to the north of the Eastern Taurus and in the south of the Sivas basin,among Divriği-Sincan and Kangal towns. In this study, it has been aimed to define structural evolution of theregion in the light of main geological characteristics.The basement of the area is represented by a mosaic that is made up of Lower Paleozoic clastic rocks,Upper P ale ozoic-Mesozoic platform type carbonates of the Taurus Relative autochton, allocthons units of UpperCretaceous ophiolitic melange and Jurassic Ophiolitic Suite. The Maastrichtian-Quaternary cover overlies themosaic uncomfortably. The lowermost of the cover starts with a poligenic conglomerate of the Maastrichtian volcano-sedimentary sequence.In the Paleocene, Divriği Granitoides intruded the basement tectonic units and also the Maastrichtianvolcano-sedimentary sequence, as well. In the following, from lower to upper levels, Eocene shallow marinedeposits, Upper Oligocene-Lower/Middle Miocene lacustrine to fluvial rocks, Upper Miocene-Lower Pliocenefluvial to lacustrine deposits, Upper Pliocene-Quternary fluvial elastics to volcanics, alluvium and terracedeposits overlie unconformably the older rock units, respectivelyIn the studied area, Pre-Maastrichtian paleotectonic structures are mainly represented by the overthrustsplunging to the north. Along these overthrusts, allocthonous units obducted the Taurus Relative Autochton.Maastrichtian-Lower Pliocene transitional tectonic structures are represented by the folded systems in the NNWSSE trending to the north, in the NE-SW trending to the south of the region. On the basis of this setting, NEESSW compression is dominant to the north, NW-SE compression is dominant to the south of NE-SW trending riseof the basement rocks, which is made up of paleotectonic units. Upper Pliocene-Quternary Neotectonics structures are represented by conjugate NE-SW and NW-SE trending faults and N-S trending normal faults whose lateral slips is not more than 1 km.On the basis of main geological data presented above, it is suggested that ophiolites and ophioliticmelange of the region moved from north to south, and obducted over the Taurus Relative Autochton. The emplacement of the allocthonous units had been completed before Maastrictian time, and the granitoides had been intruded the region after paleotectonic period.Maastrichtian-Lower Pliocene cover has been folded under the control of the compression in differenttrending processes. In the end of transitional tectonic period, paleotectonic units outcroped along NE-SWtrending rise of the basement rocks in the middle of the study area.Upper Pliocene-Quaternary units of the Neotectonic period have not been folded and NW-SE trendingright lateral and NE-SW trending left lateral conjugate faults and N-S trending normal faults occurred under thecontrol of N-S directing compression. These structures have formed in accordance with the neotectonic processes representing North Anatolian Fault (NAF) and East Anatolian Fault (EAF) systems.