The article analyzes the latest seismic data obtained during detailed seismic surveys in the development area of the Tyuysky, East Tyuysky and Biavashsky post-sedimentary trough-like troughs (“small grabens”), previously identified within the Republic of Bashkortostan on the northern slope of the Bashkir arch and in the Annunciation basin. The oil prospecting areas of the considered “small grabens” acquired after the discovery in the 1960-1980s. of the last century on the southeastern outskirts of the ancient East European platform with new oil and gas accumulation zones controlled by sedimentary grave-like troughs in terrigenous Devonian. Unlike the latter, post-sedimentary trough-like troughs are distributed along the section from Riphean-Vendian to Middle Carboniferous deposits (Vereiskian horizon), which corresponds to their geological characteristics as post-sedimentary disjunctive structures. It is shown that the interpretation of the seismic record indicates the phased development of the post-sedimentary trough-like troughs. In the Riphean-Vendian and Upper Paleozoic, semi-regional post-sedimentation micro-grabens resumed upon activation of tectonic phases as distinct disjunctives, whose morphological features weakened up the section. At the last - Vereiskian - stage, a shallow (2-3 km wide) shallow deflection was formed with a disjunctive western side and a flexure-like plicative eastern one. The oil-controlling role of post-sedimentary trough-like troughs has so far been proved only fragmentarily, but the latest seismic data allow us to detail their structure, the dynamics of their development and the influence of the conditions of their phased transformation on the formation of potential hydrocarbon traps.
The work demonstrates methodological techniques that allow using the capabilities of modern seismic packages, including obtaining information on the geomorphology of post-sedimentary trough-like troughs cavities in time.
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