Geochemistry And Formation Environment Of The Wushifeng Mountain Ophiolite In The Region Of TuoTuoHe River,Qinghai

The WuShiFeng Mountain Ophiolite in the region of TuoTuoHe River, Qinghai which is new place will bestudied in this paper. The type of rocks and age are conformed basing on detailed regional geological surveyand Geochemistry. The background of tectonic and mineralization are also discussed simultaneously. The timeof initial cracking and evolution of the ancient Tethys and the Northward extension of The JinSha river suturezone are analyzed Combining with previous data.The WuShiFeng Mountain Ophiolite with low level research located in the Ulan Ulla-the Jinsha Riversuture zone is between north QiangTang plate and Bayankala plate. Serpentinized Iherzolite is the mainlithology of metaperidotite.The differentiation of magma is instructed by mafic index. The mafic magma hashigh degree of fraction crystallization with the mafic index63in gabbro. Low degree of Si and Mg is thebasalts characteristic, low degree of crystallinity instructed by mafic index higher than original magma. Thecontent of K is extraordinary high as a result of disseminating of seawater.The samples are all fall into thebasalte zone in the TAS diagram of basalte. And in Zr/TiO₂-Nb/Y discrimination diagram, most of the samplesfall into the alkaline basalts and andesites/basalt transition area.The content of rare elements in metaperidotites are higher than Chondrite. Rare earth distribution patternfor light rare earth is enrichment with right model, due to experiencing strongly partial melting action and thenMetasomatized by fluid. Trace elements are higher than the original mantle, showing rich mantle feature. Rareearth elements of Gabbro and wall of dykes have slightly enrichment with right distribution mode. Originalmantle normalized trace elements distribution patterns instruct enrichment of Sr, K, Rb, Ba（LILE）, and havingN-MORB geochemical characteristic. The content of REE in basaltes are also in the high level. Rare earthelements is rich in light rare earth with right mode with no Ce, Eu abnormal basicly. The characteristics of thisunit are similar with E-MORB. The results of original mantle normalized for basalts show that the degree ofhigh field elements （Nb and Ta, Zr, Hf） is low, enrich Sr, Rb, Ba （LILE）. N-MORB normalized trace elementsdistribution pattern for basalts shows the "slight uplift" type with the characteristic of basalte in the plate.The characteristics of MORB and IAT can be instructed through analyzing the major and trace elements ofbasaltes in WuShiFeng mountain ophiolite. Two characteristics, MORB and SSZ are indicated by the contentand ratio of inactive elements, such as Th and Ta, La and Ta. But the MORB characteristic is the main position.It formed in the Mid-Ocean Ridge environment prompted by the field geological features and geochemicalcharacteristics of the WuShiFeng mountain ophiolite.Paleo-Tethys in the region of TuoTuoHe River was archipelagic ocean pattern basing on the combinationof rocks and radiolarian assemblages and comparison of the time with the provisional regional. ThePaleo-Tethys opened in Early Carboniferous and closed in Late Permian as a result of Yangtze plate wedgingthe westward oblique subduction. The Jinsha River northward extension should be subject to the Yushu areaand turned westbound extention to the Hoh Xil region. According to remote sensing to interpret the results ofthe survey area and the actual localization profile measurement analysis, and finally initially identified the WuShi Feng in the southeast region has the effect of Cu, Ni, Co and Zn mineralization. Further work need to bedone.