Original paper

Balacita Piedmont. A model of formation and evolution

Boengiu, Sandu; Avram, Sorin

Abstract

The geological structure, the evolution and its implications in the formation of the piedmont emphasize the pre-piedmont phase and the piedmont phase. Two distinct overlapped units can be recognized in the geological structure of this piedmont, namely the basement of the Wallachian Platform made up of Precambrian, Palaeozoic, and Mesozoic deposit which were definitively consolidated by the end of the Cretaceous, and the Neozoic overlying strata (Cenozoic).The formation of the piedmont dates back to the Romanian age (Piacenzian-Gelasian), when sands and fine gravels from Gornoviţa platform were deposited by the Pelendavian transgression (MN16a). They were deposited through numerous deltas at the mouths of the rivers that came from the Southern Carpathians, the Transdanubian Carpathians, and from the Stara Planina; thus, the shore of the lake continuously increased in height and gradually forced the shores to reach the areas the deposited materials came from.In order to obtain a clear image of the Quaternary evolution of this piedmont, it has to be taken into account the neotectonic movements occurred during the Wallachian phase, which started in the Late Pliocene and continued in the Early Pleistocene, as well as their effects upon the studied area.The Pasadena neotectonic phase manifested through the raising of the piedmont deposits Northwestwards within the Bălăciţa Piedmont. There also occurred the reactivation of the Motru fault and of the faults that limits the raised area Balş - Optaşi; all these led to the gradual movement of the Olt eastwards and of the Jiu westwards. The slide of the Danube southwards has to be attributed to this neotectonic phase as well, as it developed during several thousands of years.

Keywords

neotectonic phasepiedmont evolutionbalacita piedmont