The paleoreconstruction of sedimentation conditions at Beshpagirskoe deposit of the Stavropol Krai based on the results of pebble morphology investigation

Abstract

The morphology of pebbles provides important information for lithological-facial and paleogeographic constructions. The shape of the pebbles carries quite a variety of information about the geological processes of the distant past. Today, there is a large number of foreign and domestic studies devoted to the material and granulometric composition of psephites, while much less attention is paid to the morphological characteristics. Although very often it is the shape of the pebbles that can unambiguously resolve the issues of determining their genesis. Debris shape analysis includes the degree of contour rounding or roundness and the ratio of the three axial dimensions of the pebble: length, width and thickness. Based on the ratio of linear dimensions, judgments were made about the genesis of deposits, the direction of flow, the possibility of redeposition. The most popular are two factors: the shape factor of the fragment and the isometric factor. Conclusions: the end result of the genesis of the pebble material of the Beshpagirskiy quarry is the river alluvium of the ancient river network, subsequently rounded and polished in the coastal delta zone of the Sarmatian Sea. The flat-topped uplift of the Stavropol arch in the middle–upper Sarmatian can be considered the source of the supply of coarse-grained material. The research is of great interest for the search for mineral deposits.