Platinum-Group Element Analyses of Serpentinites in the Eastern Central Alps, from Davos (Switzerland) to the Valmalenco (Italy)

摘要: Serpentinite occurrences in the Pennine nappes of eastern Central Alps (between Davos, Switzerland and Valmalenco, Italy) display varying metamorphic grades from north to south. In they consist Mesozoic ophiolitic lherzolite tectonite south form a (pre-)Mesozoic ultramafic complex. Samples both types were analysed for Pd, Pt, Rh, Ru Ir, some cases also Cr, Cu, Co Ni. Mean values are 3 ppb Pd 15ppb Pt; Ir below detection limits 1, 20 100ppb, respectively. Low contents may be related low degree partial melting, which is reflected by abundance chrome-spinel; ratio Pt probably typical ‘alpine’ peridotites Alps. A relatively homogeneous platinum-group element pattern serpentinites lack any correlation with mineralogy, petrography, or geochemical features most likely an inherited mantle sources percentage melting but might redistribution connection serpentinization regional metamorphism.