ON THE FORMATION MECHANISM OF POSTRIFT INTRACONTINENTAL SEDIMENTARY BASINS AND THE THERMAL CONDITIONS OF OIL AND GAS GENERATION

Abstract

The analysis of geological and geophysical data on Late-Cenezoic rift zones indicates that the anomalous mantle occurring in asthenospheric upwellings beneath these rift zones has a relatively low density, this being conditioned only by its heating and partial melting. After the crystallization of the liquid phase and cooling, this material becomes more dense than the mantle part of the lithosphere beneath the adjacent regions, which leads to isostatic subsidence of the crustal surface and to formation of postrift sedimentary basins. Numerical modelling of this process shows that the theoretical curve of basin subsidence is in line with empiral data. The theoretical reconstruction of paleogeotherms indicates the important role of the sedimentary infill of paleorifts in oil and gas generation.