Investigation of structure styllious and the crustal structure of the eastern pontides orogenic belt with geophysical methods

Investigation of Structure Styllious and the Crustal Structure of the Eastern Pontides Orogenic Belt with Geophysical Methods The Eastern Pontide active continental margin extending along the Black Sea coast comprises of the three sub-tectonic unites based on their lithology and facies associations, from north to south, as the northern zone, the southern zone and the axial zone. Left lateral movement of the Arabian-African plates with respect to Eurasia plate and opening of Atlantic Ocean controlled the geologic evolution of the Eastern Pontides. In this area NE, NW and E-W trending fault systems separate these three zones and play an important role in active tectonic of the Eastern Pontides. In this study, the tectonic structure, Moho topography and depth of Curie point of the region were tried to determine. To find out the fault systems that control the tectonics of these three different zones of the Eastern Pontides, the horizontal gradient map of the gravity data was prepared. A number of lineaments are seen on the horizontal gradient map of the gravity anomaly data. It is deduced that these lineaments trending E-W, NE and NW directions must separate the major structural zones of continental crust of Eastern Pontides. To estimate the crustal s tincture of the region, the power spectrum method, a statistical approaching technique, was used. This method provides a relationship between spectrum of the anomalies and the depth of sources in the frequency domain. The Power spectrum method was applied to bouguer gravity and magnetic data of the Eastern Pontide Orogenic Belt, respectively, to determine the Moho and Curie point depth. In the Eastern Pontides, the depth of Moho varies from 35.6 km to 45.1 km. On the other hand, it is determined that the Curie point depth changes between 17.4 and 31.2 km. The gravity inversion method was also used to investigate the Moho surface. It is determined that there is a good agreement between the depths obtained from power spectra analysis and depth of the Moho estimated from the gravity inversion. KeyWords :Eastern Pontides, Gravity, Magnetic, Crust Structure, Moho, Conrad, Crystalline Basement, Curie Point Depth, Tectonic Structure, Gravity Inversion