Characteristics of early Paleozoic granite-pegmatite and associated lithium-beryllium mineralization in the Tugeman area, Altun orogenic system, northwestern China

We discovered that biotite granite is associated with biotite–oligoclase–microcline pegmatite and gneisses biotite granite is associated with two–mica microcline–albite pegmatite in Tugman area. A combined study of the field investigation, petrography, geochronology, and major-trace element of granite and pegmatite was performed in this study. The results indicate that pegmatites can be formed during both highly fractionated and less-evolved stages of granite formation, but only highly differentiated granites are favorable for the Li and/or Be mineralization; The Tugeman granites formed during the late Cambrian–Middle Ordovician (500–440  Ma) and can be divided into three groups related to the northward subduction of the Central Altun Ocean crust at 520–490 Ma, the closure of the Central Altun Ocean at 490–480 Ma, and post-collisional extension inducing by slab break-off and delamination at 480–440 Ma.