PRECARPATHIAN AND TRANSCARPATHIAN LANDFORM EVOLUTION IN THE PLIOCENE-PLEOSTOCENE AND AT EARLY STAGES

Abstract

The Sarmatian-Pannonian and Pontian-Pliocene stages are most important in the landform evolution of the Inner Precarpathians and Solotvyn basin. Due to the intense elevations in the upper Miocene, the Precarpathian Sea was pushed to the east and northeast. On the land freed from the sea, a hydrographic network was created, and rivers moved along the retreating sea in Northeast and Southeast directions. Original river valleys were of diagonal and inline outflow directions unlike modern transverse valleys. The Pontian-Pliocene is associated with the final phase of Carpathian and Precarpathian tectogenesis, and the proof is the undisturbed Pliocene denudation surface (Hofstein, 1985) or the upper denudation level (Teisseyre, 1933). The Solotvyno basin had continental regime before the Mukachevo basin had, so the Solotvyno basin got denudation and denudation-accumulative surfaces formed. These include the oldest denudation “Kichersky Level” researched by H. Alferyev (1948), which is believed to date to the early Pannonian. Younger denudation and denudation-accumulative surfaces are consistent with the Precarpathian and Transcarpathian regions. In the Precarpathian region, most authors distinguished two denudation-accumulative surfaces (terraces) – Krasna and Loyeva, and in the Transcarpathian, three – Dilotska, Boronyavska and Shardynska. In the Precarpathian region, they first identified pediments (Kravchuk, 1971), dating back to the Pliocene – early Pleistocene. Subsequently, I. Hofstein suggested that they should be dated the late Pliocene by analogy with the Transcarpathian pediments of Ye. Mazur (1963), but he did not deny that their formation continued in the Pleistocene. The prolonged weakening of the elevation in the early Pleistocene led to the predominance of lateral erosion, expansion of valley bottoms, and intense erosion of ancient terraces (denudation-accumulating surfaces). The analysis of terrace complexes in the Precarpathians and Transcarpathians makes it possible to determine the average heights of the Pliocene-Pleistocene elevations, which confirms the synchronicity of the landform evolution in these regions. Key words: denudation and denudation-accumulative surfaces; terraces; pediments; Pliocene-Pleistocene elevation; Precarpathians; Transcarpathians.