THE GEOCHEMICAL INHERITANCE FROM WEATHERED BASEMENTS TO DETRITIC BASINS: A CASE STUDY IN SARDINIA, ITALY

Prospecting studies in the tectonic trough that extends from S to N in Sardinia, have led to the discovery of mineralized formations in the basal terrigenous sedimentary rocks of a Miocene transgression. The mineralised assemblage consists of copper sulfides and oxides, suggesting fluctuations of redox conditions in near-shore, neutral to high-pH environments. Both clastic materials and metals came from Tertiary volcanic edificies where the weathering and erosion processes affecting the basement under ancient climates influenced the nature of sedimentary supply. Evidence of transport, composition of pore waters, pH-Eh conditions during diagenesis and concentration of metals enabled to a construction of the mineralizing process.