Warunki geologiczne występowania węglowodorów w osadach ordowiku i syluru syneklizy perybałtyckiej na tle jej rozwoju

Abstract

GEOLOGICAL CONDITIONS OF OCCURRENCE OF HYDROCARBONS IN ORDOVICIAN AND SILURIAN DEPOSITS FROM THE PERIBALTIC SYNECLIZE IN THE CONTEXT OF ITS DEVELOPMENT Summary Variable thickness of Lower Paleozoic sedimentary cover over vast areas of Peribaltic syneclize and its margins indicates remarkable and differentiated mobility of Precambrian Platform basement, That mobility was expressed primarily in broad-radial downwarpings of crystalline substratum, commonly taking place during periods of acceleration of tectonic movements. Moreover, disjunctive tectonics was marked, resulting in characteristic changes in lithofacial development and thickness of deposits over some smaller areas. Formation of local structures over the area of Lower Paleozoic syneclize has always been related to repeated disjunctive disturbances, since it involves a reaction on every stage of acceleration of tectonic movements. History of formation structures of block of type began in the early Cambrian, but essential phase of their development appear to be related to synorogenic Variscan activity. The role of faults and other zones of tectonic discontinuity, commonly submeridionally or subparallely oriented was also significant. These zones facilitated migration of hydrocarbons form deeper to shallower parts of Lower Paleozoic basin. All principal instances of oil occurrence in Peribaltic syneclize were recorded in the proximity of dislocations. In the complex of Ordovician-Silurian deposits from the eastern part of the syneclize, lumpy limestones of the Lower Llandoverian age are the only possible hydrocarbon collectors. Oil tarps of the lithological type, complicated by faults, are expected here.