CONTRIBUTION OF MULTIVARIATE GEOCHEMICAL ANALYSIS AND MINERALOGICAL STUDY IN THE CHARACTERIZATION OF SEDIMENTS - THE MIOCENE-PLIOCENE BOUNDARY IN THE SORBAS BASIN (SE SPAIN)

A mineralogical study and multivariant geochemical analysis have been carried out to determine the sedimentation processes and the influence of surrounding rocks on sediments. Analyses were made on the clay fra ction of sediments and on bulk samples of rocks from nearby reliefs in the Sorbas Basin (SE Spain). Source rocks were identified by statisti cal analysis of trace elements and by comparison of the crystallograph ic parameters of phyllosilicates in sediments and supposed sources. Pa laeoenvironmental conditions are recorded by specific elements in the clay minerals. The study of the B and Mg content and of the different types of smectites and palygorskite found in distinct areas has permit ted a description of these conditions for this Basin. In this way, dif ferent types of deposition environment, showing varying degrees of con finement and influence from marine or continental water, have been dis tinguished.