The Messinian salinity crisis onset in Albania: An integrated approach by bio-magnetostratigraphy and rock magnetic analyses

Abstract

We carried out an integrated stratigraphic study aiming the identification of the onset of the Messinian salinity crisis (MSC) in the Peri-Adriatic Depression, a region forming the northern front of the Albanides fold-and-thrust belt. The onset was identified in the Kavaje area within an interval of euxinic shales representing a time-equivalent deposit of the Primary Lower Gypsum of stage 1 of the MSC, recognized elsewhere in the Mediterranean realm (CIESM, 2008). This interpretation is supported by the integration of magneto-stratigraphic (base of Gilbert chron) and bio-stratigraphic data (last influx of T. multiloba; last occurrence of foraminifera) calibrated with precessional cyclicity recognized in the pre-evaporitic sediments by rock magnetic analyses. Detailed sedimentological observations revealed that the overlying Gips-Sharrë Gypsum unit consists of chaotic and clastic evaporites floored by a regional-scale erosional surface. Their 87Sr/86Sr values (0.708937 to 0.708967) are typical of stages 1–2 of the MSC. Consequently, their assignment to the Resedimented Lower Gypsum unit is here proposed. The halite deposits, that have been intercepted by boreholes above the Gips-Sharrë Gypsum unit, have been also framed in the RLG. Our results confirm the applicability of the MSC 3-stage model (CIESM, 2008) also in the eastern side of the Adriatic Sea.