Geology and Hydrocarbon Resources of the Outer Carpathians, Poland, Slovakia, and Ukraine<subtitle>General Geology</subtitle>

Abstract

The purpose of this chapter is to provide the general overview of the stratigraphy and tectonics of the Polish, Ukrainian, and adjacent parts of the Slovakian Outer Carpathians. The Polish and Ukrainian Outer Carpathians form the north and northeastern part of the Carpathians that expand from the Olza River on the Polish–Czech border to the Ukrainian–Romanian border. Traditionally, the Northern Carpathians are subdivided into an older range, known as the Inner Carpathians, and the younger ones, known as the Outer Carpathians. These ranges are separated by a narrow, strongly tectonized belt, the Pieniny Klippen Belt. The Outer Carpathians are made up of a stack of nappes and thrust sheets showing a different lithostratigraphy and tectonic structures. Generally, each Outer Carpathian nappe represented separate or partly separate sedimentary subbasin. In these subbasins, enormous continuous sequence of flysch-type sediments was deposited; their thickness locally exceeds 6 km (3.7 mi). The sedimentation spanned between the Late Jurassic and early Miocene. During the folding and overthrusting, sedimentary sequences were uprooted, and generally, only sediments from the central parts of basins are preserved. The Outer Carpathian nappes are overthrust on each other and on the North European platform and its Miocene–Paleocene cover. In the western part, overthrust plane is relatively flat and becomes more and more steep eastward. Boreholes and seismic data indicate a minimal distance of the overthrust of 60–80 km (37–50 mi). The evolution of the Northern Outer Carpathian Flysch basins shows several tectonostratigraphic stages. The first period (Early Jurassic–Kimmeridgian) began from the incipient stage of rifting and formation of local basins. The next stage (Tithonian–Early Cretaceous) is characterized by rapid subsidence of local basins where calcareous flysch sedimentation started. The third period (Late Cretaceous–early Miocene) is characterized by compression movements, appearance of intensive turbiditic sedimentation, and increased rate of subsidence in the basins.