PALEORECONSTRUCTION OF THE LATE CAMBRIAN STRUCTURE OF THE IGARKA-KHETA PERICRATONIC SUBSIDENCE IN CONNECTION WITH EVALUATION OF PETROLEUM POTENTIAL PROSPECTS

V. S. Staroseltsev

Structure of the Igarka-Kheta pericratonic subsidence delineated by the author together with V. M. Lebedev in 1967 is specified taking into account recent results of the CDP-2D seismic survey. The analysis of total and strata thicknesses alterations of Middle Cambrian-Lower Carboniferous deposits in the Igarka-Norilsk region was supplemented with a considering of the Upper Cambrian deposition conditions on variously oriented seismic profiles of the Khantaiskaya area. Such analysis serves as a basis for distinguishing the Igarka-Kheta pericratonic subsidence. Changes in inclinations of Upper Cambrian clinoform deposits reflect the configuration of the Igarka-Kheta subsidence southern edge depending on spatial orientation of seismic profiles. The eastern and northern borders the Igarka-Kheta subsidence are defined more exactly as a result of the Kystykhtakhskaya deep well drilling. The key guidelines for evaluation of petroleum potential prospects of positive structures adjacent to subsidence are stated on the grounds of changes in the paleostructural pattern of the Igarka-Kheta pericratonic subsidence in Late Cambrian and regularities of zonal distribution of Devonian salts.

Key words: pericratonic subsidence, isopachytes, salt fluid trap, petroleum potential prospects.

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