Structural setting of Gabbros in the Ağaçören Granitoid: Implications from Geological and Geophysical (Resistivity) Data

Abstract

Gabbro blocks are locally exposed in the Ağaçören granitoid which is located to the east of Lake Tuz. Similar Gabbro blocks are also observed in the other granitoid introsions od the Central natolian crystalline Complex but their structural relation with the granitic rocks, which are the dominant lithology in the granitoids, is not well defined in the field. This study, directed towards the determinati9on of the structural relationships between granite and gabbro, is concerned with the geological studies and geophysical surveys carried out to obtain apparent resistivity values at Kapak Tepe and Havuzkoyağı Sırtı which are located in the central part of Ağaçören granitoid. The measurements, with 400meter electrode spacing, were taken at atotal of 6 stations using Schlumberger Vertical Electrical Sounding method. The resistivity contour diagrams (pseudo-sections) obtained using the apperent resistivity data, reveal that the gabbros exposed in these areas are not roof-pendants but introsive bodies continuing at depth. In parts of the study area the gradual transition of gabbro to a dioritic composition towards the granite contact, the sinisoidal contact traced between granite and diorite and the mineralogical and textural features observed along this contact suggest that the granite and gabbro are coeval intrusions an that the observed features occured when both intrusions were at magmatic stage.