Interpretation of the gravity and magnetic anomalies of the Cappadocia region, Central Turkey

Abstract

The Cappadocia region, located in Central Turkey, is characterized by widespread lava flows and volcanoclastic deposits dating from Miocene to Quaternary. Gravity and aeromagnetic anomalies of the region appear to present similar high and low amplitude regions, although the aeromagnetic anomalies exhibit a rather complex pattern which is thought to be caused by remanent magnetization. The low-pass filtered aeromagnetic map shows a deep-seated magnetic anomaly which may be linked to the widespread volcanic activity at the surface. The pseudogravity transformation of the upward continued anomaly has been constructed. The pseudogravity anomaly demonstrates some form of clockwise rotation. This anomaly was modelled by means of a three-dimensional method. The top and bottom of the body are at 6.3km and 11km (including the flight height) from the ground surface, respectively. This deep body is ellipsoidal and extends along an E-W direction, which is in line with the regional stress direction deduced from GPS measurements. A new mobilistic dynamo-tectonic system appears to explain the body's E-W elongation. The modelled body may be the source for the inferred geothermal energy of the region. Magnetic measurements were carried out on oriented rock samples collected from outcrops of ignimbrites and basalts, providing directions and intensities of remanent magnetization, susceptibilities and Koeningsberger (Q) ratios. Standard deviations of remanent directions of the Natural Remanent Magnetization (NRM) display a wide scatter implying unreliability of the surface data. Reduction to pole (RTP) transformation of magnetic anomalies was successful with the induced magnetization angle despite the complex pattern of magnetic anomalies.