COMPARATIVE ANALYSIS OF THE GEOLOGICAL STRUCTURE, SEDIMENTATION CONDITIONS, AND PETROLEUM POTENTIAL OF THE MESOPOTAMIAN AND TEREK-CASPIAN FOREDEEPS

Abstract

The formation of foredeeps in the Alpine Orogenic Belt was related to convergence of the Eurasian and African-Arabian continental blocks. The Arabian Plate existed in the Mesozoic as the southern passive margin of the Tethys Ocean. In contrast, the Scythian Plate with the Terek-Caspian Foredeep in the southern part was situated in the rear zone of a complex transitional zone that included marginal volcanic arcs and marginal seas. Although the composition of Mesozoic-Cenozoic rocks in both regions is significantly different (carbonate-terrigenous composition in the Terek-Caspian Foredeep and evaporite-carbonate composition in the Mesopotamian one), they demonstrate obvious similar features. Diapirism is typical of both foredeeps: deformation of salts in the Persian Gulf area; deformation of clays and, possibly, salts in the Terek Depression; and presence of the principal oil pools in fractured and porous-fractured carbonate reservoirs. The significantly higher oil/gas-bearing (hereafter, petroleum) potential of the Mesopotamian Foredeep is related to the presence of evaporites, as regional screens for fluids at several levels of the section.