Sedymentacja środkowego dewonu w regionie łysogórskim (profil Świętomarz-Śniadka)

Abstract

SEDIMENTATION OF THE MIDDLE DEVONIAN IN THE ŁYSOG6RY REGION (ŚWIĘTOMARZ-ŚNIADKA SECTION) Summary The described section represents one of longest studied, key localities of the Middle Devonian developed in clay- mudstone-carbonate Łysogóry facies in northern part of the Holy Cross Mts. The obtained data made it possible to subdivide Middle Devonian strata into 4 formations and 5 members which were subsequently correlated with units earlier distinguished in another key section - Grzegorzowice-Skały section (35; see Fig. 1 ). The conodont record reveals presence of the lowermost part of the ensensis Zone within the middle member of the Skała Formation (Sitka coral-crinoid limestone). The Eifelian-Givetian boundary passes either within these strata or the overlaying Sierżawa Member. The sedimentological analysis showed that all the studied strata belong to epicontinental facies varying from shallow littoral zone to deeper subtidal. It should be noted that the present analysis failed to give support for graywacke or flysch character of the Świętomarz Formation. In contrary to some earlier views (6, 36, 51 ), the unit does not represent any geosynclinal facies but it rather reflects a stage of silicoclastic (noncarbonate) shelf sedimentation developing under conditions of activation of eastern land area as a source of terrigenous material, presumably due to some climatic changes.