Kartowanie wyników badań petrograficznych osadów górnego czerwonego spągowca z obszaru Pomorza Zachodniego

Abstract

MAPPING OF RESULTS OF PETROGRAPHIC STUDIES ON THE ROTLIEGEND IN WESTERN POMERANIA Summary The paper presents lithofacies characteristics of the Upper Rotliegend, in the section of which two diastrophic- sedimentary megacycles may be differentiated (4): an older - Drawsko Fm., and younger - Noteć Fm. The studies involved petrographic analyses of core material from several dozens drillings. The most important properties of these formations were plotted in classification triangles (Figs. 1-3 - Drawsko Fm., and Figs. 5-7 - Noteć Fm.). Subsequently, arithmetic means of the properties were calculated for individual drillings and maps of regional variability of the properties compiled (Figs. 4, 8-13). The maps of content and composition of lithoclasts (Figs. 4, 8, 9) make possible drawing some conclusions concerning location and structure of areas subjected to denudation and acting as sources of detrital material for origin of the studied rocks, as well as intensity of resedimentation processes. Conditions of sedimentation of sandstones are defined by content of silt- and clay-size material in these rocks (Fig. 1 O). Figure 11 shows distribution of sediments characterized by the highest and lowest values of the coefficient of primary structural maturity, and Fig. 13 - such distribution of values of the coefficient of secondary maturity. The highest contents of components of chemical origin in sandstones (Fig. 12) appear related to activity of post-volcanic hydrothermal solutions. The attempt to compile results of numerous petrographic analyses in the form of maps, presented here, is of the regional type. The selected properties of rocks and their interrelations are important for reconstructions of paleogeography of the relevant formations and make possible more accurate evaluations of collector properties of the clastic rocks.