| This dissertation is object on Tangbale ophiolitic in Western Junggar, Xinjiang. Systemic researching the character of ophiolitic of rock combination, petrology, formtive age,petrochemistry, geochemistry, tectonic setting, tectonic significance and so on.(1)Tangbale ophiolitic distribute the southwest of Junggar basin, kazakhstan-Junggar plate Tangbale-Kalamaili Paleozoic complex trench arc zone, the width is about 4 to 8km, consist of kind of ultrabasicrock, has a complete sequence of ophiolite.(2)The position of serpentinite is lowest as matrix, gabbro,diabase and basalt accumulate on the serpentinite, and siliceousrock cover with basalt. contact relation between each sequence was fault because of structural demolished.(3)The gabbro, a sequence of ophiolitic, LA-ICP-MS zircon U-Pb dating shows that ages are disperse and young, stand for tectothermal event or metamorphic age, which can't stand the gabbro's true formation age. so synthesize former formation data, consider that Tangbale ophiolitic was formed about 447Ma-531Ma, belong to Cambrian-Ordovician.(4)The basalts from the Tangbale ophiolitic display tholeiitic in composition with enrichment in LILEs (e.g., Rb, K and Ba), depletion in HFSEs (e.g., Nb, Ti, Zr and Hf) and weak or no Eu anomalies, depletion Nb, Ta generally, geochemistry character show Tangbale ophiolitic formed in back-arc basin setting。(5)Insusceptible elements, such as Zr, Nb and Y, are employed to discriminate the nature of magma source of depleted mantle.(6)This study and previous work constrains north westward subduction model in the West Junggar for the Cambrian-Ordovician.
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