Depositional systems and cyclicity in the intracratonic Early Jurassic basin in Poland

Abstract

A number of depositional systems and sub-systems have been recognized within the Lower Jurassic clastic deposits of the Polish Lowlands. These are: fluvial, deltaic, swampy (with swampy-lacustrine and swampy-lagoonal sub-systems) and siliciclastic shelf system (with shallower and deeper shelf sub-systems -the former includes brackish shelf facies). On the basis of their vertical succession and lateral changes, the Lower Jurassic sediments have been subdivided into five transgressive-regressive cycles. The lower-most deposits are included into the regressive phase of the last Triassic cycle. These cycles have been compared with the eustatic curves of B. U. Haq et al. (1988) and A. Hallam (1988).