Sedimentary environments...

Sedimentary environments of Pleistocene glacigenic deposits of crevasse accumulation in eastern Poland


Research problem. Pleistocene glacigenic sediments of crevasse accumulation are marked in Polish Detailed Geological Maps, however they are still weakly recognized in glacigenic relief of Poland. They were rarely documented in the literature, and interpreted as supraglacial filling of ice crevasses with glacifluvial or glaciolacustrine deposits. The examined deposits were assigned to eskers or kames, but only a few researchers made a research on sedimentary environments of their deposits.

Similarly to polish research, in the international ones, Pleistocene, glacigenic sediments of crevasse accumulation was firstly interpreted as fillings of stagnant ice crevasses. They were educed from eskers and recognized as crevasse fillings on the base of morphological, geological and location conditions. Later, similarly to Poland, features of these sediments were interpreted as kames. Nowadays, forms of crevasse accumulation are distinguished only in today-glaciated landscapes. However, they have utterly different morphological and geological characteristics from so-called Pleistocene crevasse forms, especially contrary deposits, i.e. glacial till. It results from their deposition in different ice dynamic state crevasses i.e. surging ice.

Aim of research. Lack of detailed recognition of Pleistocene deposits of glacigenic crevasse accumulation, and consequently principles of distinguishing these forms of crevasse accumulation within Pleistocene glacigenic relief encourage to detailed research, in which the main aim is documentation of types of sedimentary environments. It will allow to make their genetic interpretation and defining Pleistocene crevasse accumulation forms. Lack of such definition pose a gap in geomorphological research, causing various interpretations of crevasse accumulation forms.

Expected effect. An expected result of research is distinguishing types of Pleistocene, sedimentary environments of crevasse deposits, and palaeoenvironmental and palaeogeographical conditions of their development. In consequences, assignment to Pleistocene glacial forms and argument to distinguishing crevasse accumulation forms in Pleistocene glacial relief, marked on Polish Detailed Geological Maps.