Reconstitution of the groundwater palaeoflow of Kessarat cave, Antelias valley, Lebanon : A geomorphological approach in palaeohydrological records analysi

Poster, International Quaternary Association Congress (INQUA), Bern, SwizerlandSeveral studies on karst systems and geomorphology has been initiated in Lebanon recently by EDYTEM laboratory UMR 5204-CNRS, France in collaboration with Saint Joseph University of Beirut. One of these researches aims at reconstituting: i) speleogenic evolution based on geomorphologic indicators, ii) karstogenesis reconstitution related with the downcutting of the Mediterranean hydrographic network (Antelias and Kelb river), iii) palaeogeographical reconstitution of these tow valleys. Tow caves have been chosen in each valley and a morphogenic analysis has been completed in each cave with a geomorphologic approach. One of the main caves studied, downstream Antelias valley, is Kessarat cave with its underground river and its 4.6 km gallery development. After the morphogenic study of the cave, a 7.6 m. height section has been completed in the Jonction gallery on a sand slope deposit. Observations as well as grain size and morphoscopic analysis on sand layers have lead us to reconstitute the deposit dynamics and the palaeoflows of the underground river such as velocity variations and flows directions. These results helped us to identify some aspects of the geomorphological environments of the Kessarat underground river. These results have been demonstrated within the karstic context and the morphogenesis scenarios of Kessarat cave