Enrichment of Mantle‐derived Fluids in the Formation Process of Granitoids: Evidence from the Himalayan Granitoids around Kunjirap in the Western Qinghai‐Tibet Plateau

Abstract Taking the Himalayan granitoids around Kunjirap in the western Qinghai‐Tibet plateau as an example, the authors present in this paper the characteristics of the granitoids rich in mantle‐derived fluid components and discuss their rock‐forming mechanism. The research results indicate that the rock assemblage of the studied granitoids involves diopside syenite‐diopside granite‐biotite (monzonitic) granite, consisting mainly of K‐feldspar, oligoclase, quartz, iron‐phlogolite, diopside and edenite. The rocks are rich in mantle‐derived fluid components of volatiles including F, alkali metal elements such as K, Na, Rb, Sr and Ba, and radiogenic heat‐producing elements such as U and Th. They were generated by the influx of mantle‐derived fluids into the lower crust to give rise to partial melting during the lithosphere thinning in the Qinghai‐Tibet plateau.