The internal geometry and lithofacies pattern of the Upper Cretaceous-Danian sequence in the Polish Lowlands

Abstract

The paper presents a set of maps illustrating the internal geometry of the Upper Cretaceous-Danian sedimentary sequence in the Polish Lowlands. Qualitative lithofacies are used for reconstructions with the dominant lithofacies component and accessory components indicated. The following maps are produced: (1) base Upper Cretaceous structural map; (2) Upper Cretaceous (including Danian) thickness map; (3) thickness map of succession K3 (Cenomanian–lower Turonian, excluding the upper Albian cycle K3-I, which is the lowermost cycle of succession K3, but formally belongs to the Lower Cretaceous); (4) succession K4 (upper Turonian–Danian) thickness map. The maps of successions K3 and K4 illustrate the post-inversion geometry of the basin for the pre-inversion (Cenomanian–lower Turonian) and syn-inversion (upper Turonian–Danian) successions. Thickness analysis shows an increasing difference in subsidence rate during the Late Cretaceous between the areas extending on the two sides of the present-day Mid-Polish Swell. Much higher subsidence rates during deposition of succession K4 occurred in the area extending to the SW of the swell. The maximum subsidence zone migrated with time from the Pomeranian and Kujavian segments towards the Kujavian and Lublin segments. The lithofacies pattern is presented in seven maps constructed for individual eustatically and tectonically controlled cycles: K3-II–K3-III (early Cenomanian–early late Cenomanian), K3-IV (latest Cenomanian–early Turonian), K4-I (late Turonian–Coniacian), K4-II (Santonian–earliest Campanian), K4-III (late early Campanian–earliest Maastrichtian), K4-IV–K4-V (late early Maastrichtian–late Maastrichtian) and Pc-I (Danian–?earliest Selandian).