Genesis and tectonic significance of the Kuda ophiolites in western Kunlun Mountains, Xinjiang

The Kuda ophiolites hosted on the northern side of the Kangxiwar strike-slip fault in western Kunlun Mountains, Xinjiang are made up of dismembered metamorphic peridotites, cumulate rocks and massive pillow basalts, and overlain by the variegated pyroclastic rocks and clastic rocks with turbidites. The Sinian to Early Ordovician is interpreted as the major periods for the formation of the oceanic basin for the Kuda ophiolites, and the emplacement of the ophiolites may represent the important records for the plate motion in the study area during the Late Proterozoic to the Early Palaeozoic. The chemical characteristics show that the Kuda peridotites occur in the abyssal mantle peridotite fields, and have lower CaO, Al₂O₃ and FeO^T contents than those in the primitive mantle. The mineralogical characteristics of the peridotites and geochemical signatures of the basalts indicate that the Kuda ophiolites have seen about 30% of partial melting of the peridotites, and recorded the tectonic transition from the mid-oceanic ridge to the subduction zone, similar to those of the Yarlung Zangbo suture zone.