Investigation of Crustal Thickness in Eastern Anatolia Using Gravity, Magnetic and Topographic Data

Abstract

The tectonic regime of Eastern Anatolia is determined by the Arabia-Eurasia continent-continent collision. Several dynamic models have been proposed to characterize the collision zone and its geodynamic structure. In this study, change in crustal thickness has been investigated using gravity, magnetic and topographic data of the region. In the first stage, two-dimensional low-pass filter and upward analytical continuation techniques were applied to the Bouguer gravity data of the region to investigate the behavior of the regional gravity anomalies. Next the moving window power spectrum method was used, and changes in the probable structural depths from 38 to 52 km were determined. The changes in crustal thickness where free air gravity and magnetic data have inversely correlated and the type of the anomaly resources were investigated applying the Euler deconvolution method to Bouguer gravity data. The obtained depth values are consistent with the results obtained using the power spectrum method. It was determined that the types of anomaly resources are different in the west and east of the 40°E longitude. Finally, using the obtained findings from this study and seismic velocity models proposed for this region by previous studies, a probable two-dimensional crust model was constituted.

Vertical and Horizantal Analysis of Crustal Structure in Eastern Anatolia Region

“…Additionally, the reasons of the negative amplitude parts obtained in figure 5 may be originated from the crustal problematic area (between the depth 20 km and 40 km) which was represented by Türkelli et al (2003), Zor et al (2003), Pamukçu et al (2007), Keskin et al (2003Keskin et al ( , 2007Keskin et al ( ), fiengör et al (2003, Pamukçu and Ak盤 (2011) in figure 7.…”

“…In the area between NAFZ and EAFZ near 100000 meter latitude, the structure transition in figure 4, the negative amplitude closures in figure 5 and the regions show high seismic activity in figure 6 were determined as the area which showed decreasing crustal thickness (Pamukçu et al, 2007), decreasing S-wave velocity , decreasing Curie depths and increasing heat flow (Pamukçu et al, 2014). Additionally, Pamukçu et al (2007) pointed out that in their Euler deconvolution study results, the 1400000 meter longitude was a border and the lithospheric structures may be different in west and east sides of this border.…”

“…Besides, the structures in convergence systems are involved in one of the tectonic component such as plateaus, suture zones, lithospheric flexures on the fore-plate, the deformation zones on the fore-plate/ back-plate, orogenic collapse/tension zones and the structures are formed with the uplifting of topography. The tectonic components for Eastern Anatolian region were examined in details in the studies of Al-Lazki et al, 2003;Gök et al, 2003;Türkelli et al, 2003;Sandvol et al, 2003a,b;Zor et al, 2003Zor et al, , fiengör et al, 2003Keskin, 2003;Pamukçu et al, 2007;Pamukçu and Ak盤, 2011;Pamukçu et al, 2014.…”

“…In these studies generally, it was emphasized that the large-scale shortining and thickening in the crust was started by the tension of the Arabian-Anatolian Plates convergence. The new approaches were presented by the studies (Al-Lazki et al, 2003;Gök et al, 2003;Türkelli et al, 2003;Sandvol et al, 2003a,b;Zor et al, 2003;fiengör et al, 2003;Keskin, 2003, Pamukçu et al, 2007Pamukçu and Ak盤, 2011;Pamukçu et al, 2014) realized after 2001 in Eastern Anatolia. In these new models, it was pointed out that the crustal thickening was not in the mentioned scale in previous studies (Rotstein and Kafka, 1982;McKenzie, 1972McKenzie, , 1976Dewey et al, 1986;Pearce et al, 1990).…”

“…In these new models, it was pointed out that the crustal thickening was not in the mentioned scale in previous studies (Rotstein and Kafka, 1982;McKenzie, 1972McKenzie, , 1976Dewey et al, 1986;Pearce et al, 1990). Pamukçu et al (2007) determined the crustal thickness and the model of the region by using gravity data. Pamukçu and Ak盤 (2011) calculated the effective elastic thickness for explaining the mechanism of the topography which compensates the crustal thickness.…”