(a) E1* sample with a brownish matrix revealing the presence of goethite and (b, c) PPL and XPL of the polygenic breccia with different clasts (serpentinite, chromitite, amphibolite). Micritic and sparitic calcite can be distinguished in the XPL image. (d) XPL image of the carbonated border of a clast and the micritic calcite and residual serpentine in the matrix. (e, f) Images acquired in cathodoluminescence of a carbonated border of a serpentinite clast and authigenic calcite in the matrix. cal: calcite; goe: goethite; spt: serpentine.