The Absolute Age First Determination of the 3rd Terrace Deposits from Transilvania, Using Optically Stimulated Luminescence Method

For determining the absolute age of the terrace deposits, a geomorphosite located on the left side of Someşul Mare river, southeast of Rebrişoara was selected, which includes a fragment of the tread of the 3<sup>rd</sup> terrace (20-21 m relative altitude) and the cuesta slope, facing north the Făgetului Hills. The question regarding the age of fluvial terraces has been long debated in Romanian geomorphological literature age since the beginning of the 20<sup>th</sup> century. Many geomorphologists have carried out studies wherein the question of the age of the terraces, both inside the Carpathian curvature and outside, was raised. Most of the studies carried out for the terraces on the rivers of the Transylvanian Basin indicated the age of the 3<sup>rd</sup> terrace as Wurmian. Until recently, most assumptions related to the age of the terraces were based on the correlation between terraces and/or by dating the paleontological fossils discovered in the terrace deposits. Recent studies, on the other hand, use high-precision methods to determine the ages of terrace formations. Researchers, use methods like the Infrared-stimulated luminescence dating (IRSL) and SAR-OSL (Optically Stimulated Luminescence). Within this context, the present study focuses on the attempt to determine the age of the 3<sup>rd</sup> terrace in the corridor of the Someșul Mare river. In the alluvial formations of this terrace, two geologic drillings were carried out from where several samples were collected. They were subjected to OSL analysis at the Luminescence Dating Laboratory, Department of Geoinformatics, Physical and Environmental Geography, University of Szeged, Hungary. The results showed an older age of the 3<sup>rd</sup> terrace than it has been believed until now.