Oscylacje transgresywne morza doggerskiego między Gorzowem Wielkopolskim i Zakrzewem

Jerzy Znosko




A revision of the Middle Jurassic stratigraphy in the sections from Gorzów Wielkopolski to Zakrzewo has demonstrated that some thin sandstone beds occur between the Liass and transgressive upper Kujavian (Vesoulian). The sandstone beds belong to the zone Stephanocreas humphriesianum of the Upper Bajocian, and to the zone Parkinsonia subarietis of the Middle Kujavian. These beds represent some post-erosional, previously wide and thicker cover of Bajocian and Middle Kujavian deposits.
The area between Gorzów Wielkopolski and Zakrzewo, belonged at the Aalenian, Bajocian, Lower Kujavian and Middle Kujavian times to the marginal zone of the basin.
The well examined secttions of the Middle Jurassic deposits in the area of Częstochowa, in the Kujawy region, and within the area in study, allow us to determine the following development of booth sedimentation and erosion:

Aalenian – marine ingression; continuation of sedimentation within the basin

Lower and Middle Bojocian – regression in the marginal parts of the basin; erosion of the Aalenian deposits

Upper Bojocian – transgression in the marginal zones and revival of sedimentation

Lower Kujavian – regression in marginal zones ; erosion of the Upper Bajocian deposits, at places also of the rests of the Aalenian deposits;

Middle Kujavian (zones Parkinsonia subarietis and Parkinsonia parkinsoni) – transgression in marginal zones and revival of sedimentation

Middle Kujavian (zone Parkinsonia schloenbachi) – regression in marginal zones, erosion of the deposits of the zones P. parkinsoni and P. subarietis, et places also of the older deposits of Middle Jurassic age (naturally if they were not removed previously). At that time, the Upper Liassic series were probably eroded
Upper Kujavian (zone Parkinsonia ferruginea) – wide transgression in marginal zones and revival of sedimentation;

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