Rola obszaru krakowskiego w sedymentacji osadów górnej jury Wyżyny Krakowsko-Częstochowskiej

Abstract

A ROLE OF THE CRACOVIAN REGION IN THE LATE JURASSIC SEDIMENTATION OF THE CRACOW-CZÊSTOCHOWA UPLAND (SOUTHERN POLAND). Summary During the Late Jurassic the Cracow region showed specific features different from the neighboring areas. These are the following: (i) lower thickness of preserved Upper Jurassic strata (about 250 m in eastern part and much less in western part) compared to that in northern parts of the Cracow-Częstochowa Upland, and (ii) distinct lithologic differences. The main feature that enables to identify the so-called “Cracovian Sedimentary District” from the northern regions of the Cracow-Częstochowa Upland, is the intensive development of massive facies which commenced between the early and middle Oxfordian. The unique position of the Cracovian region is highlighted by a low subsidence during the Late Jurassic resulted from the presence of low-density granitoid mass in the basement. Uncompensated by subsidence sedimentation was brought about by a distinct elevation on a carbonate ramp that formed in the Cracovian region during the Oxfordian. This environment particularly favored the development of carbonate buildups. An intensive, aggradational growth of these uncompensated by subsidence structures led to formation of elevated barrier separating the shelf margin from the open ocean.