The Plio–Pleistocene Demise of the East Carpathian Foreland Fluvial System and Arrival of the Paleo-Danube To The Black Sea

Abstract

This paper studies the Porat Formation (Fm.), which was deposited along the NE margin of the Dacian Basin part of the East Carpathian foreland (ECF) during the Pliocene and Early Pleistocene. We use a review of stratigraphic data in combination with lithofacies and sedimentary architecture analysis to interpret the Porat Fm. as a large sandy alluvial basin infill with an aggradational structure, consisting of cyclic successions of shallow sandy high-energy braided rivers. Aggradation of the Porat Fan was governed by subsidence of the Dacian Basin, along with a northerly supply of water and sediment from the Carpathians. Along the southern margin of the area the fan entered the Reni–Izmail-Trough, which formed the periodically active gateway between the Black Sea and Dacian basins. Along this trough, the Porat Fm. is developed in a different facies, discerned as the Dolynske Member (Mb. 1), which accumulated in the channel of a large river interpreted as the paleo-Danube. According to mammal stratigraphy of the Porat Fm. this continental-scale river had reached the area by the Gelasian to early Calabrian. The Porat alluvial infill indicates a stable water supply from the Carpathians, which explains the ecologically mixed fauna in its deposits: moistened forested alluvial plain-valleys were present between the zonally semi-arid steppe interfluves. The Porat Fm. and the previously studied late Miocene Balta Fm. are key elements for further in-depth study of the terrestrial evolution (tectonic–sedimentary–relief) of the ECF and north-western Black Sea coastal regions.

An integrative approach highlights the discrepancy in the genetic, phenotypic, and presumptive taxonomic structure of Phoxinus (Actinopterygii, Leuciscidae, Phoxininae) in Bulgaria

“…For example, the paleohydrology of the Lower Danube is very complex, and this section of the river basin is relatively young in its modern configuration. The Miocene basins of central and southeastern Europe (Pannonian and Dacian), which once contained the Paratethys Sea with their own independent river drainages, were progressively filled with sediments during the Neogene and transformed into the catchment area of the proto‐Danube and finally that of the modern Danube, starting from the mid‐to‐late Miocene and ending during the regional Romanian stage, around 4.15–1.8 Ma (De Leeuw et al, 2017, 2020; Krézsek & Olariu, 2021; Magyar et al, 2013; Matoshko et al, 2019). Therefore, the scattered mosaic occurrence of P. csikii could be a result of the paleohistory of independent rivers on the western and northern slopes of the Balkan Mountains, which underwent significant rearrangements during the Plio‐Pleistocene to reorient their drainages (e.g., Osam and Yantra) toward the Lower Danube (Angelova, 2003a).…”

Early–Middle Pleistocene Magnetostratigraphic and Rock Magnetic Records of the Dolynske Section (Lower Danube, Ukraine) and Their Application to the Correlation of Loess–Palaeosol Sequences in Eastern and South-Eastern Europe

“…Currently, we have not reached any Late Pleistocene deposits at Dolynske. The alluvial deposits and mammal fauna of the Dolynske area were studied extensively [217,218]. The so-called Porat Formation, a large sandy alluvial basin developed in different facies, is discerned as the Dolynske Member, which accumulated in the channel of a large river interpreted as the palaeo-Danube.…”

“…The so-called Porat Formation, a large sandy alluvial basin developed in different facies, is discerned as the Dolynske Member, which accumulated in the channel of a large river interpreted as the palaeo-Danube. According to mammal stratigraphy of the Porat Formation, this continental-scale river had reached the area by the Gelasian age to the early Calabrian age [218].…”

From the Eastern Paratethys to the Pontocaspian basins

“…In its evolution, the Dacian Basin went through three main stages: 1) The late middle Miocene-mid-late Miocene interval with brackish to polyhaline water environments and the most extensive connectivity with the Euxinian (Black Sea) Basin (Palcu et al, 2017); 2) The mid-late Miocene-mid-Pliocene interval with changing salinity from brackish to freshwater and restricted connectivity with the Euxinian Basin (Stoica et al, 2013); 3) The mid-Pliocene-Pleistocene interval, in which the basin became overfilled and accumulated fluvial and limnic deposits (Jipa and Olariu, 2009;van Baak et al, 2015b;Jorissen et al, 2018;Matoshko et al, 2019).…”