La chronologie IRSL des séquences lœssiques de l'est de la Roumanie

Résumé Fr En

La méthode de datation IRSL sur feldspaths alcalins (40-60μm) est appliquée aux lœss du Pléistocène supérieur et moyen récent (

The IRSL dating method is applied to alkali feldspar grains (40‑60μm) from Upper and Middle Pleistocene (< 300 ka) loess deposits from two loessic sequences, at Mostistea and Mircea Voda, in southeastern Romania, following the previous IRSL investigation of the Tuzla loessic section performed by Balescu et al. (2003), within the same area. The IRSL ages corrected for fading, support the assignment of the three upper loess horizons (L1, L2 and L3) to the last three Pleistocene glaciations (MIS 2 to 4, MIS 6, MIS 8) and confirm that the Last Interglacial soil (MIS 5e), whose chrono- stratigraphic position was still debated, corresponds to pedocomplex S1. These IRSL data result in a long chronology contrasting with the previous short chronology proposed by Conea (1969), who assigned S1 and S2 pedocomplexes to Last Glacial interstadials. As a consequence, the chronology of the Middle Palaeolithic open air sites of Romania, so far restricted to the Last Glacial cycle, strongly requires reconsideration. Finally, these IRSL results confirm that the transition from humid to drier interglacial conditions reflected in the development of the first chernozem pedocomplex (S2) within the loessic sequences, took place in southeastern Romania during MIS 7.