Determination of the Crustal and Thermal Structure of the Erzurum-Horasan-Pasinler Basins (Eastern Turkiye) Using Gravity and Magnetic Data

Abstract

The Erzurum-Horasan-Pasinler basin, which surrounds Miocene rocks, is oriented approximately E-W and is located in Eastern Anatolia (Turkiye). East Anatolia, where ophiolitic and young volcanic rocks are widespread, is situated in the Alpine-Himalayan fold-thrust fault belt. The NW-SE trending North Anatolian Transform Fault Zone and the NE-SW trending East Anatolian Transform Fault Zone, formed by the compressional regime of East Anatolia, control the main tectonics of the study region. While the Moho and Conrad depths of the study region are 43.0 and 20.9 km, respectively, the average sedimentary thickness has been determined to be 5.2 km by using the power spectrum method. On the other hand, it is found that the depth of the Moho in the region varies from 41.0 to 44.5 km and the depth of the Conrad discontinuity varies between 22 and 26 km, as computed using empirical equations. The basement of the sedimentary layer is calculated to be 6 km by using inversion results applied to the residual gravity data. The Curie point depth and average heat flow value in this region are calculated as 18.0 km and 89.1 m Wm(-2), respectively. Geotherm calculations reveal that the Moho temperature is 1,028.0 A degrees C based on the crustal model. The high heat flow values obtained are attributed to tectonic activities and melting of the lithospheric mantle caused by upwelling of the asthenosphere.