FINDINGS OF THE PRE-DNIPRO FOSSIL MOLLUSCAN FAUNA IN WESTERN UKRAINE

Abstract

Over the past two decades, we have been studying a wide range of Quaternary sediments in western Ukraine in close cooperation with Ukrainian and Polish scientists. The sediments often contain paleofaunal remains such as bones of large and small mammals, mollusk shells and ostracods. During the period of research, we have discovered and studied more than 30 locations of molluscan fauna. Most of them date back to the Upper Pleistocene. Contrarily, there are few sites that would represent the fauna that inhabited the study area before the Dnipro glaciation. The same can be noted by analyzing the results of research by predecessors, in particular M. Kunytsia and I. Melnychuk, authors of the Geological Atlas of Galicia. We found molluscan fauna in six points. Two of the identified locations, namely Kalynivka and Liuboml, are located within the Volyn Polissia and are confined to the sediments between the Tiligulian moraine and Dnipro glacial and water-glacial deposits. Three more sections are located in Podillia. These include the Medzhybizh section (located on the left bank of the Southern Bug River to the west of the village of the same name), the Skala Podilska (discovered within the Burdiakivskyi special quarry on the northern outskirts of the Mezhyhirtsi (an outcrop on the left bank of the Dniester downstream near the confluence of the Hnyla Lypa River). The last one is found the Halych section, which reveals the structure of the ancient (fifth) Dniester terrace near the confluence of the Lukva River. The issue of detailed stratification and correlation of the studied sections remains challenging. This is due to the long-time influence of denudation factors such as glacial exhumation, slope processes, etc., as well as the different history of development of the territory under study. Molluscan fauna represents both warm (interglacial) and cold (glacial) conditions. The oldest fauna was found in the sediments of the Shyrokyne climatolith (Skala Podilska section) and represents warm interglacial conditions. It was also possible to identify fauna from loess formations, which indicates the dominance of cold arctic-boreal-alpine conditions in the accumulation of loess material in the early Pleistocene (MIS 20). Keywords: malacofauna; Pleistocene; climatolith; loess; alluvium.