Lithological and geomorphological indicators of glacial genesis of the upper Quaternary strata in the lower courses of the Nadym River.

Analysing the genesis of Quaternary sediments is important for understanding the glaciation history and development of marine sediments in the northern part of the Western Siberia. The key features of sedimentation and landform formation have been characterized for the first time in an example of a lithological column from the lower sources of the Nadym River. A comprehensive analysis was performed on the lithological, petrographic, and geomorphological data from the upper stratum of Quaternary sediments of the column. Based on the shape and morphology of quartz grains, some features of glacial processes for some layers of the studied sections were identified and analysed with special attention to the environmental history. A petrographic study of the boulder samples was carried out, which showed that the majority of samples are boulders of glacial origin according to their shape and texture. For the first time, digital terrain models were applied to study of the key plot where the lithological column is situated, which made it possible to identify the specific terrain areas that were most likely formed by glaciation. It is suggested that extensive lacustrine-alluvial plains existed in the Nadym River Basin, which was represented by postglacial sites. Such a concept provides a lithological basis for understanding the reasons for the formation of the present and recently formed environments and landforms. Therefore, it could be possible that local glaciation in the region of the Nadym River's lower course had an effect on the formation of the stratification of the layers of Quaternary origin. [ABSTRACT FROM AUTHOR]