Budowa geologiczna regionu Krakowa

Abstract

GEOLOGICAL STRUCTURE OF THE CRACOW REGION, SOUTH POLAND Summary Deposits composing the Cracow region represent a time span extending from the Precambrian through the Holocene. Clastic deposits of the Caledonian structural stage were laid down in a NW-SE trending depression, which was subsequently transformed into the Cracovide fold zone (Fig. 1). The Variscan structural stage, represented by carbonate Devonian and Lower Carboniferous deposits, as well as by clastic Upper Carboniferous sediments, was also deformed within a zone showing the similar orientation. Numerous intrusions and extrusions of volcanic rocks belonged to this stage. The Alpine stage is composed of the Permian, Jurassic, Cretaceous and Miocene deposits. The Upper Jurassic and Upper Cretaceous periods are represented by epicontinental carbonate deposits. During the Laramian orogeny, boundaries of tectonic structures revealed the same orientation as those of the Hercynian stage. During Paleogene times, however, a remarkable change took place, leading to the formation of W-E trending tensional faults (Fig. 1). A similar pattern persisted in the Miocene. Dominant features of the Tertiary tectonics in the Cracow region are horsts built up from Jurassic and Cretaceous deposits, separated by grabens filled with Miocene clays. The impact of thrusting of the Carpathian nappes, protruding from the south onto sub-Miocene basement in that area, was in significant. Both in Paleogene and Pliocene times, planation surfaces and diversified erosional morphology were being formed. In the Quaternary, in turn, repeated cycles of accumulation and dissection of alluvial covers, as well as within loess covers thenselves took places.