THE RIVER DNIESTER VALLEY, A LONG RECORD OF LATE-CENOZOIC FLUVIAL EVOLUTION WITHIN THE EASTERN CARPATHIAN FORELAND AND EAST EUROPEAN PLATFORM MARGIN

Abstract

The Dniester valley is a spectacular example of a degrading bedrock fluvial system at the contact between the East European platform and the Carpathian orogen. This study is based upon a combined lithofacies-architecture-morphological study. The complex approach replaces an erstwhile conventional pure geomorphological one, eliminating the shortcomings and inaccuracies, providing a more justified stratigraphy and extended version of the valley evolution. The history of the valley and associated fluvial systems (alluvial fans, delta, coastal alluvial plains) occurred at the end of the Miocene and continued through the Pliocene-Quaternary (11–12 Myr). It unfolded against the background of the retreat of the Eastern Paratethys sea, including the ‘foreland’ and ‘cratonic’ periods and their seven stages. The spatial organisation of the river’s drainage networks, sedimentary environments, fluvial styles and landforms changed gradually during these intervals and experienced rapid reorganisation when they were replaced. All this left characteristic features within the valley’s four established plain reaches. The tectonic control on these changes through flexural deformation and accelerated uplift/tilt within the platform was decisive while the impact of climatic changes remained problematic. The issues of the river terraces correlation, base-level oscillations, influence of the rock’s erodibility and non-fluvial processes are also considered.