Geological and Tectonic Significance of Aqiang Ophiolitic Tectonic Melange in Southern Yutian, West Kunlun

In recent years, a set of metamorphic peridotite, serpentinite, metagabbro, diabase, basalt and other rock assemblages with ophiolite characteristics have been newly mapped in Aqiang of Southern Yutian, West Kunlun. Among them, the metamorphic peridotite and serpentine have the characteristics of low SiO₂, high MgO and low REE. Most samples of gabbro, diabase and basalt are characterized by low K₂O<1% and TiO₂≈1.5%. The characteristics of rare earth elements and trace elements are similar to those of N-MORB and E-MORB. Comprehensive analysis shows that the ophiolite occurs in a large-scale ocean basin and belongs to mantle plume(P) origin.The average weighted ages of the dating samples are(545.5±9.1)Ma and(440.0±4.8)Ma, which confirm that the formation age is in Cambrian-Ordovician. The Qimanyute ophiolite melange in the adjacent western area is also the geological records of the Early Paleozoic ocean-continent transition events in the central and northern Kunlun block.The study is of great significance to the tectonic evolution of the west Kunlun.