SELTENENG OPHIOLITE AND ITS TECTONIC SIGNIFICANCE IN SHANSHAN,OF XINJIANG

Ophiolite formation in Serneng region was constituted of serpentine,gabbro,basalt and corresponding tuff.It ultramafic component was similar to the average of lherzolite in China,F/M was 8.03～9.74,and ∑REE was 1.26×10-6～4.69×10-6.Its gabbro was low in Si,high in Mg,low in K and Rb-Sr: K2O 0.17%～0.29%,Rb 2.41×10-6～3.41×10-6,Sr 82×10-6～163×10-6. Its basalt falled in the mid-oceanic ridge basalt area in the major components of F1-F2-F3 figure and Ti-Y figure. MORB normalized trace element figure of gabbro and basalt was similar to the almost horizontal line of MORB. All these features showed that Serneng ophiolite was different from Huangshan-type Cu-Ni-bearing mafic-ultramafic complex of Xinjiang in nature. They also indicated this ophiolite occurred in ocean basin,but not back-arc basin. Serneng ophiolite,Qiategali ophiolite and Kangnan ophiolite comprised Katayoulu ophiolite belt,as the vestiges of north Tianshan ocean in Carboniferous. This belt was also the sutured line of Jueluotage structural belt and Haerlike-Yilianhabierga structural belt in its north.