Direction of the Aalenian transgression in the area of the Mid-Polish Trough

Jolanta Świdrowska

Abstract


The hitherto existing arguments for three different directions of the Aalenian transgression have been analysed in the paper. An explanation that the transgression followed due to downwarp movements along faults bordering the trough was further a basis for creation of theoretical suggestions on the direction of transgression. Palaeogeographic conditions in the neighbourhood of two presumed straits: the south-eastern and western ones - have been discussed. The following features are discussed: a possible marine connection, intensity of subsidence, lability of the adjacent denudation areas, presence of open-sea nectonic fauna, presence of Ca/Mg carbonates in cement of deposits and the geotectonic similarity to the situation in the Toarcian. Based on these data, it has been concluded that the Aalenian sea entered the area of the Mid-Polish Trough through a depression formed in the foreland of the Bohemian Massif.


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