Kame or moraine? A sedimentological study of a glaciomarginal landform at Niedźwiedziny (Great Polish Lowland)

Abstract

A sedimentary succession in a gravel pit at Niedźwiedziny was investigated in order to determine its origin: kame or moraine. The gravel pit is located in an isolated hill of approx. 600 m long and 250–400 m wide. The succession is built of glaciofluvial deposits: a sandy/gravelly unit in the lower and middle parts, overlain by diamicton. Five lithofacies have been distinguished, which represent two facies associations: (1) a fluvial association evolving from a high-energy to a transitional to a shallow braided river on an alluvial fan, and (2) an association of cohesive deposits representing a glacigenic mass flow. The interpretation is based mainly on palaeocurrent data and differs from conclusions by earlier investigators. The ice-marginal zone is characterised by a large variety of glaciomarginal forms. Their sedimentology, morphology and palaeogeography are determined by successive phases of deglaciation. The re -sults of the present study show that the character of the deglaciation in the study area changed with time from frontal to areal deglaciation.