Characteristics and Tectonic Environment of Larelaxin Granite Plutons in Ritu County, Tibet

As a component in the Qiangtang granite district of the Tanggula-Dongda mountain granite zone, Lare-laxin Granite Plutons mainly contain such rock types as biotite hornblende diorite, biotite hornblende quartz dio-rite, biotite hornblende quartz monzonite , biotite granodiorite, biotite adamellite, biotite granite. And Larelaxin Granite Plutons are of such geochemical characteristics as being rich in Si, K, being depleted in Ti, Mg, Fe, Ca, and ACNK 1.1, and patterns of REE distribution standardized by chondrite inclining right in V-shape, being rich in LREE and relatively depleted in HREE and Eu. They were formed in Early Cretaceous Period as poly-syn-collisional syntectic granites.