Sedimentary-exalative features in Cu-mineralized sandstones at the base of the Miocene: the example of Pala Mantedda (NW Sardinia, Italy)

Prospecting in the northern part of Sardinia, within a N-S-trending tectonic trough has led to the discovery of a number of mineralized sections in the terrigenous sediments that were produced during a Miocene marine transgression. The mineralization occurs at the contact between pyroclastics and clastic sediments and consists of sulphide phases in chalcedony representing the surficial deposition of exhalative fluids connected to the Tertiary volcanism. The source of metals was probably of both hydrothermal and sinsedimentary origin.