Individual particle analysis of Western Mediterranean sediment cores, Rhône suspended matter and Sahara aerosols — investigation of inputs to the sediments

Abstract

Individual particle analysis using electron probe X-ray microanalysis was performed on sediment cores from the Gulf of Lions (Western Mediterranean Sea), on atmospheric aerosols sampled in Corsica and originating from Northern Africa, and on Rhône suspended matter. Cluster analysis was done to yield major particle types and kriging spatial analysis was applied to obtain the distributions of the particle types in the sediment surface layers. For three sediment cores, the depth profiles of particle groups were examined. The predominant particle types composing the sediment material in the Gulf of Lions were found to be Si-rich particles (quartz and biogenic silicate), aluminosilicate minerals (illite, kaolinite, chlorite) and Ca-rich particles (aragonite, calcite, high-Mg calcite). During the diagenesis, dissolution and crystallization processes occurred, yielding the substitution of quartz and Si-rich particles by calcium carbonates in deeper sediment layers. Only a small amount of Fe-S-rich (pyrite) particles was found in the analyzed sediments. An evident impact of Rhône derived and offshore eroded material was noticed in the sedimentation area investigated. Yet, the input of Northern Africa aerosols to the sediment vicinity was not so evidently noticeable from these results.