MOHO DEPTH IN THE SOUTH CASPIAN BASIN ESTIMATED FROM GRAVITY FIELD DATA AND LOCATION OF HYDROCARBON RESERVOIRS

The South Caspian Basin (SCB) is a geologically complex and diverse region of significant scientific interest due to its hydrocarbon resources and intricate crustal structure. This study provides an updated interpretation of the SCB’s crustal configuration using gravity-derived data, with particular emphasis on delineating Moho depth and the influence of its variations on petroleum basins. The crustal structure of the basin is assessed using Bouguer gravity anomalies, incorporating terrestrial and marine gravity measurements, and processed with spectral analysis methods. Power spectrum analysis was applied to estimate the depths of subsurface mass distributions affecting the gravity field, enabling separation of regional and residual anomalies and providing an initial reference depth of Moho. These results served as input for Parker–Oldenburg inversion, an iterative Fourier-based technique used to model the Moho surface by minimizing discrepancies between observed and calculated gravity anomalies. The integrated approach reveals substantial lateral variations in Moho depth, ranging from approximately 42 km in the Absheron–Prebalkhan zone to about 29 km in the central SCB. Analysis of spatial correlations indicates that oil and gas reservoirs are primarily located in areas where the Moho surface is deeper and along gradient zones marking abrupt depth changes. These findings enhance understanding of the complex tectonic evolution of the SCB and provide valuable constraints for predicting potential hydrocarbon locations in this tectonically active and data-scarce region.