LITOFACJE OSADÓW ŚRODKOWEGO I PÓŹNEGO HOLOCENU MIERZEI WIŚLANEJ NA ODCINKU PRZEBRNO-PIASKI

Abstract

LITOFACIES OF THE MIDDLE AND LATE HOLOCENE SEDIMENTS IN THE PRZEBRNO-PIASKI SEGMENT OF THE VISTULA SPITAbstract. Holocene sediments of the Vistula Bar are represented at the bottom by fluvial Preboreal-Early Atlantic sands. They are overlain by a thin layer of biogenic-mineral deposits. The upper part of the Holocene section is represented by barrier marine sediments deposited during the Late Atlantic-Subatlantic period. These barrier marine sediments were subjected to granulometric and cluster analyses in order to distinguish three lithofacies and consistently six subfacies: A (A1, A2), B (B1, B2), and C (C1, C2). Following the parameters of Folk and Ward (1957) and types of deposits (C-M diagram) presented by Passega-Byramie (1964,1969), lithodynamic processes that affected the origin of the subfacies were interpreted. A spatial configuration of these subfacies reflects long-term changes of water reservoir's hydrodynamics, which control depositional processes in each zone of the sea floor due to sea-level variability. The changes in the spatial facies pattern are in good agreement with palaeogeographic development of the Baltic Sea during the Middle and Late Holocene. The subfacies analysis is supported by radiocarbon dating.