GEOCHEMICAL CHARACTERISTICS OF GRANITOIDS ALONG THE WESTERN MARGIN OF THE CENTRAL ANATOLIAN CRYSTALLINE COMPLEX AND THEIR TECTONIC IMPLICATIONS

The closely related assemblage of igneous and metamorphic rocks that lie within a triangular area approximately bounded by the Tuzgolu Fault, the Ecemis Fault and the Izmir-Ankara-Erzincan Suture and between the lines connecting Ankara, Sivas and Nigde is called the Central Anatolian Crystalline Complex (CACC). The granitoids cropping out within the CACC can be divided areally into three groups: (1) a large number of individual small plutons which form an arcuate set and curve from NE-SW to NW-SE and extend from Sulakyurt to Nigde along the western margin; (2) a relatively narrow and smaller set of disconnected plutons extending from Sivas to Camardi along the eastern margin; and (3) a very large batholith along the northern margin exposed around Yozgat. This study deals only with the first group of rocks. Geochemical data have been used to classify the granitoids, to determine their chemical characteristics, and to estimate the possible source regions and tectonic environment of magma generation and emplacement. The geochemical data indicate that these western margin granitoids range in composition from monzonitic to granitic-granodioritic varieties, belong to the alumina-cafemic and cafemic associations and possess either a metaluminous or peraluminous character. All granitoid types display features which may indicate the presence of both S- and I-type igneous rocks. Interpretation of the trace element data suggests a syn-collisional to late/post-collisional tectonic setting and a continental crustal source for the granitoids.