Xinjiang ALeTunKunDuo Ophiolitic Melange of Geochemical Characteristics and Formation Environment

The ophiolitic melange is consisted of gabbro, plagiogranite and volcanic lava, lacking of metamorphic peridotite, ultramafic cumulate rock and diabase dike unit. The standardized distribution pattern of REE chondrite in gabbro and basic lava of ophiolitic melange, and trace elements of the primitive mantle is nearly flat. There is loss or slight loss in light rare earth, which is similar to the transitional tectonic settings of island arc(IAB) and spreading ridge(MORB), indicating that the ophiolites is probably formed in the fore-arc expansion environment of incipient arc at the bottom of SSZ Oceanic basin.