Mechanizmy sedymentacji cyklicznej osadów trzeciorzędowych w zapadliskach przedpola Sudetów

Abstract

MECHANISMS OF CYCLIC SEDIMENTATION OF TERTIARY SEDIMENTS IN DEPRESSIONS IN THE SUDETIC FORELAND Summary Several tectonic basins have developed in northern and western part of the Sudetic Foreland. They are filled with Tertiary brown-coal formation with clearly marked sedimentary cyclicity. Several sedimentary megacycles have been distinguished within the basin deposits. They appear mainly connected with allocyclic mechanisms, as tectonic movements and subsidence of basin bottom. The beginning of every megacycle corresponded one of tectonic phases of the Late-Alpine epoch. The second-order sedimentary cycles may be traced in each megacycle. The Markov transition analysis confirmed asymmetry of simple fraction cycles. The first-order Markov transition scheme has used mostly for this analysis - another types of the cycles are visible rarely. There are reversed fractional cycles, connected with deltaic sediments, and simple cycles matching the second-order Markov transition scheme. The subsidence was the most important mechanism here stimulating the second-order cyclic sedimentation. This one was connected with deposition of the very thick peat series and their internal compaction. For the most part this subsidence was compensated with the fluvial, deltaic and phytogenic deposition.