Marginal Glacial Deposits in the Southwestern Part of the Kola Peninsula

A. A. Vashkov; O. Yu. Nosova

摘要

Three belts of marginal glacial deposits have been found in the southwestern part of the Kola Peninsula. They are consistent with three retreat phases of the Scandinavian Ice Sheet in the Late Pleistocene. Clast fabric analysis and lithological investigation of the glacial deposits and morphometric analysis of the glacial relief have made it possible to identify the imbricate-overthrust and folded glaciodislocations in the marginal ice complexes. Regularities in the arrangement of the marginal glacial deposits in the region have been defined by morphometric study of the present relief. The imbricate-overthrust glaciodislocations have been found in the structure of the first and second belts of the marginal glacial deposits. They correspond to single large ridges or massifs with parallel ridge landforms. Particular fragments occur as low ridges with gla-ciofolds in their cores composed of loose bedrock. The third belt of marginal glacial deposits consists of moraines of marginal folds and rare imbricate moraines interbedding with fluvioglacial deposits. In the present relief, this belt consists of ridge-hilly and hilly forms, and its characteristic feature is deltaic fluvioglacial deposits at the distal end of eskers. According to the clast fabric analysis and structural study of the glaciodislocations, the glacier was moving mainly along the White Sea basin eastwards during the generation phases of the first and second belts. At the time of formation of the third belt, the active glacier was advancing south and southeastwards. Each glacier retreat phase was accompanied by short-term oscillatory readvances. In the White Sea basin and on the moraine plain, glacier degradation was fast and areal in nature. Frontal deglaci-ation was characteristic for the convergence areas of the marginal glacial complexes. The new data on the structure of the glacial deposits, the structural study and clast fabric analysis of glaciodislocations implemented for the first time, and morphometric description of landforms have made it possible to reconstruct the dynamics of the last glacier cover in one of the key areas of the Kola region.

Marginal Glacial Deposits in the Southwestern Part of the Kola Peninsula

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