Fig. 4

Lithologies of the Série Rousse. a Typical glossy metallic grey appearance of the schistosity surfaces of the Série Rousse calcschists; Meina pass [2′599′280/1′105′330], Hérens valley. b Alternating grey calcitic marble and russet calcschist levels in the Série Rousse; dolomitic clasts are visible in the same outcrop; Rochers du Bouc [2′595′210/1′099′620], Dix valley. c Centimetric clasts in the Série Rousse, mainly formed by dolomites (pencil), limestones and minor quartzschists (out of the picture); Pic d’Artsinol [2′598′780/1′107′050]. d Microscopic aspect of a quartzitic marble from the base of the Série Rousse. CL: cathodoluminescence; PPL: plane polarized light. Well sorted rounded detrital quartz grains appear in violet in CL; dolomitic grains show mauve to dull orange colors; overgrowth (probably burial) cements are bright orange; zoning and/or dark rims are discordant with respect to the twinning (PPL) and could represent original variations of Mn²⁺ incorporation; Pic d’Artsinol [2′599′170/1′108′585]. e Dark levels of calcschists, calcitic marbles and dolomitic breccia (close-up picture) from the Série Rousse; La Tour [2′605′440/1′104′770], Hérens valley. f Rhombohedral automorph mineral observed in various thin sections of dark micritic calcitic marbles of the Série Rousse. Raman spectra indicate feldspar; Pic d’Artsinol [2′598′700/1′108′400]. Similar rhombohedron resulting from the silicification of automorph dolomite crystals are described in dark micrites of the “mid”-Cretaceous Joux Verte Fm. of the Breccia nappe (Dall’Agnolo 1997). g Dark non-carbonated schists outcropping 20 m above the base of the Série Rousse at La Vieille [2′602′800/1′105′540], Hérens valley