Development of relief of the Velyky Lukavets River valley near Starunia palaeontological site (Carpathian region, Ukraine)

Abstract

In Quaternary sediments filling the Velyky Lukavets River valley, at the abandoned ozokerite mine (= Ropyshche) in Starunia, perfectly preserved carcasses of large mammals were discovered in the first half of the 20th century. The study area includes a fragment of the valley between Molotkiv and Starunia, and its close vicinity. The area belongs to several morphostructural and geomorphic units of the Outer Eastern Carpathians and the Carpathian Foreland. The asymmetric, subsequent valley is a part of the Mizhbystrytska Upland, where flattened ridges and flat bulges represent fragments of planation surfaces: the upper (the Krasna level), elevated 170 m above the valley bottom and linked with the Late Pliocene, and the lower one (the Loyova level), rising at 100 m and linked with the Eopleistocene. Several flat surfaces are visible on valley slopes, probably representing river terraces formed before the Late Pleistocene. The valley attained its maximum depth during the Eemian Interglacial (OIS 5e). In the Ropyshche area, probably three terrace steps built of Weichselian and Holocene sediments (OIS 5d - 1) were developed, but their top surfaces are almost completely destroyed by mining operations. The recent, meandering river bed follows the zones of decreased cohesiveness of rocks resulting from mining activity and is becoming somewhat deepened during inundations. The transported material is mostly coarse-clastic one. The two latter factors may suggest that the river is underloaded due to declining agriculture and decreasing intensity of outwash. The top surface of the sub-Quaternary basement is deformed by subsidence and collapse of mine workings, but the relief of valley bottom allows for further exploration for remnants of large mammals not only in the Ropyscche area but along the whole studied segment of the valley, as well.