Palaeoenvironmental interpretation of a Pleistocene alluvial succession incentral Poland: sedimentary facies analysis as a tool for palaeoclimatic inferences

A Pleistocene valley-fill alluvial succession deposited in the Kleszczow Gr aben. central Poland, has been studied in the Belchatow openpit mine. The s uccession. palynologically documented to represent the Drenthe/ Warthe inte rstadial, consists of three alluvial complexes whose component lithofacies associations indicate a fluvial system evolving front temperate-climate mea ndering river to transitional-type shallow braided network, to periglacial well-developed braided river influenced by aeolian sand supply. The study s uggests that the abundance of fine-grained overbank deposits. occurrence of peats/palaeosols and fining-upward cyclothems are diagnostic attributes of perennial meandering river alluvium. which may indicate temperate climatic conditions. Periglacial braided river alluvium is recognizable by an admix ture of wind-derived sand grains with aeolian surface textures and by the o ccurrence of ice-wedge features, indicative of cold climatic conditions. Th e distinction between the two basic types of alluvium is aided by the analy sis of architectural elements and palaeocurrent directional data. The study demonstrates that sedimentological facies analysis can be a useful tool fo r the recognition of palaeoclimatic changes in Pleistocene alluvial success ions.