Platinum-group elements for the Kudi ophiolite, western Kunlun

The analyses of PGE characteristics for the Kudi ophiolite, western Kunlun, are reported in this note. The Ir-depleted anomalous ancient upper mantle represented by the Kudi mantle peridotites had been percolated and mixed by remelted oceanic crust material from a supra-subduction zone, leaving the rocks relatively enriched in Pd. The PGE contents in the Kudi cumulate pyro xenites and gabbros vary from 2.4 to 23.94 ng/g, and the highest values are in pyroxenites. The Pd/Ir ratios increase from the pyroxenites to the gabb ros. The PGE patterns for the Kudi cumulate rocks are steeply positively sl oped. The Pd enrichment in these rocks is similar to that in pyroxenites fr om the Thetford ophiolite and the Troodos ophiolite. The Kudi diabase and b asalts have low PGE contents and positively sloped PGE patterns, and are co mparable with the upper pillow lavas from the Troodos ophiolite, indicative of the environment of back-are spreading center in a supra-subduction zone .