Thermal structure of the crust in Inner East Anatolia from aeromagnetic and gravity data

Abstract

Inner East Anatolia has many hot spring outcomes. In this study, the relationship between the thermal structure and hot spring outcomes is investigated. The residual aeromagnetic and gravity anomalies of the Inner East Anatolia, surveyed by the Mineral Research and Exploration (MTA) of Turkey, show complexities. The magnetic data were analyzed to produce Curie point depth estimates. The depth of magnetic dipole was calculated by azimuthally averaged power spectrum method for the whole area. The Curie point depth (CPD) map covering the Inner East Anatolia has been produced. The Curie point depths of the region between Sivas and Malatya vary from 16.5 to 18.7km. Values of heat flow were calculated according to continental geotherm from the model. The heat flow values vary between 89 and 99mWm−2. Heat flow values are incorporated with surface heat flow values. Gravity anomalies were modeled by means of a three-dimensional method. The deepest part of the basin (12–14km), determined from the 3D model, are located below the settlement of Hafik and to the south of Zara towns. Two-dimensional cross sections produced from the basin depths, Curie values and MOHO depths. Based on the analysis of magnetic, gravity anomalies, thermal structures and geology, it seems likely that the hot springs are not related to rising asthenosphere, in the regions of shallow CPDs (∼16.5km), and mostly hot springs are related to faulting systems in Inner East Anatolia.