The Texture Of Ophiolite Ocean Crust In YZSZ,Xigaze,Tibet

Ophilite in Xigaze well preserved of YZSZ was concerned as the remnants of New-Tethys.In this study,the samples we found in Deji accord with the definition of boninite,of which the Si O₂(wt%)>53%,Ti O₂(wt%)<0.5%,Mg O(wt%)>8%.The samples in Deji lack Olivine Phenocryst and have Pl Phenocryst,the REE diagrame show N-MORB trends which is differ to the U-shape of REE diagrame of IBM boninite.In terms of main and trace elements,the samples basalts-dolerite and emplacements of mantle found in different place have same source region,and stem from single parental megama.These conservative element sensitive to dehydration patial melting of slab like Zr?Hf?Nb?Ta and Th have clear relevance with unconservative Y and Yb.Which indicate there is no dehydration patial melting of slab during the formation of the ophiolite oecean crust,which means the ophiolite oecean crust come into being in MOR,not in SSZ.In LLDS,the clear relevance between Mg#and Mg O?TFe O suggest the crytalization of Olivine.Incompatible elements Ni and Cr paimarily preserved in Olivine and Spinel.the clear relevance between Mg#and Ni?Cr suggest the crytalization and diffrentiation of Olivine and spinel.Ca O?Al₂O₃?Na₂O were primarily preserved in Pl and Cpx.Al₂O₃ and Na₂O were irrelevant to Mg#shows the absence of accumulation was due to the early end of the crytalization of Pl and Cpx...