Quaternary tectonostratigraphic evolution of the Vlora Basin, south-western Albania

The Vlora Bay is a roughly north-west–south-east-oriented tectonic depression located at the collision zone between the Apulian Foreland and the Albano-Hellenic Chain in south-western Albania. The bay exhibits a triangular-shaped geometry, which is the result of different tectonic phases that occurred mostly between the end of the Neogene and the Quaternary. The bay consists of two distinct physiographic sections: a shallow water marine offshore area and a recently emerged onshore sector. Along the onshore sector, Pleistocene clastic sediments filling the Pleistocene Vlora Basin crop out due to the recent uplift phases. The sedimentological and stratigraphic organization of the Vlora Basin deposits and the role played by Quaternary tectonic structures in their deposition are the main topics of this paper. A detailed field survey, supported by a geoelectrical survey, reveals a series of unconformity-bounded stratigraphic units deposited in two north-west–south-east-oriented subbasins. The two subbasins are separated by an intrabasinal, fault-bounded, pre-Quaternary morpho-structural high and are mainly filled by shallow marine to continental deposits. A detailed structural analysis shows different tectonic phases affecting the area during the Pleistocene. Additionally, the geophysical survey facilitates the reconstruction of the deep structure of the basin and provides a better definition of the basin margins. Based on both geological and geophysical data, a tectonostratigraphic evolutionary model is proposed for the Vlora Basin Pleistocene sedimentary infill. This model consists of three phases of sedimentation that were essentially controlled by fault activity and by the progressive uplift of the area.