CLIMATIC SIGNIFICANCE OF GRAIN SIZE PARAMETERS OF THE WET AEOLIAN SEDIMENTARY FILLING OF SEBKHA MHABEUL, SOUTHEAST TUNISIA: CONTRIBUTION OF THE GENETIC APPROACH

This paper aims to investigate the climatic signals within the wet aeolian sedimentary deposits of sebkha Mhabeul. The descriptive grain size distribution (mean, mode, median) was not enough to better visualize the climatic variability. The here proposed genetic approach highlighted the individualization of the four climatic stages through the primary and secondary modes and the ratio between them. Humid climatic phases are associated with higher values of secondary mode. Arid climatic stages are characterized by higher values of the primary mode. As convolution of the two previous parameters, the ratio increases due to arid climatic phases. During the arid periods of WP and Medieval Climatic Anomaly (MCA) values of the ratio are high whereas during the wet period of the Little Ice Age (LIA) values are lower. In doing so, the genetic approach is proposed as better tool to the investigation of the sedimentary environments than the descriptive one.