Tectonic structure of the Yamal-Gydan region: update on the result of integrated interpretation of geological and geophysical data
Integrated interpretation of potential fields and seismic data allowed detailing a tectonic scheme of the pre-Jurassic basal complex and sedimentary cover within the Yamal-Gydan region. Structure of the supposed Permian and Triassic above-rift troughs is updated. There are no indications of the considerable tectonic tension typical of rifting. This suggests the deeper occurrence of the Earth’s crust tension zones. Pulling apart was insignificant, while downwarping caused by the lithosphere cooling and weighing following the rifting had very large amplitudes. All this provided accumulation of superthick Permian and Triassic deposits (mostly of post-rift origin). Downwarping continued throughout the Mesozoic and was concentrated along the rift zones. As a result, large uplifts of the sedimentary cover were formed. Deep-seated lineaments mapped in the basal complex are the tectonic blocks boundaries, reverse faults, thrusts, and other inhomogeneities of the basement. In the course of the Mesozoic cover development, all the structure-forming motions occurred along these lineaments. According to many researches, these deep-seated lineaments control the position of linear waste mantle and productive zones at the top of the pre-Jurassic basal complex. The presented structural scheme of pre-Jurassic basal complex may serve as a basis for heat flow calibration when creating a model of petroleum system.