Longshore Sediment Transport in Lake Ladoga Based on Analyses of the Heavy Mineral Fraction of Sand in Coastal Sediments

Abstract—

In order to identify the directions of transport of coastal sediments of Lake Ladoga, heavy mineral fraction was extracted from sand samples collected on all types of its shores. The mineral composition, size and roundness of particles − features characterising the degree of reworking of coastal sediments − were assessed under a microscopic analysis. We identified 4 clusters with similar degrees of reworking of the source material, which, based on the results of the factor analysis, were ranked by relative transport distance from insignificant to very significant. The maximum number of samples with small transport distances was found on the northern shores of the lake, which can be explained by the location of bedrock shores − the main sources of clastic material in the lake. Samples with maximum transport distances are relatively evenly distributed along all shores of the lake. The analysis of the results showed that on all shore reaches there is a transport of heavy fraction of bottom sediments in a certain direction: on the southern shore – to the west, on the western shore – to the north, on the northern shore – to the east and on the eastern shore – to the south-east. This allows us to conclude that there is a long-term trend of coastal sediment transport along the shores of Lake Ladoga in a clockwise direction.