Timing of granite pegmatite-type high-purity quartz deposit in the Eastern Qinling, China: constraints from in-situ LA-ICP-MS trace analyses of quartz and monazite U–Pb dating

Eastern Qinling, China is one of the important rare metal metallogenic provinces with extensively distributed granite pegmatite dikes. The No. 5 granite pegmatite intruded into the granitic gneiss of the Qinling Group, and the major minerals are quartz(39.8%),K-feldspar(18.8%), albite(36.3%), muscovite(3.4%), and garnet(1.1%). Monazite U–Pb isotopic dating indicates that the No. 5 pegmatite from the Eastern Qinling was emplaced at ca. 420.2 ± 2.2 Ma, which confirms that highpurity quartz mineralization probably formed during the Early Devonian. In-situ laser ablation inductively coupled plasma mass spectrometry analysis of quartz show that quartz samples from Eastern Qinling have total trace element concentrations(Al, Ti, Sc, Li, B, Cr, Mn, and Fe)ranging from 23.2 to 52.8 ppm, slightly higher than the quartz(impurity element content from 13.4 to 25.9 ppm) of the Spruce Pine high-purity quartz deposit in western North Carolina. The No. 5 pegmatite of Eastern Qinling could be defined as one high-purity quartz deposit of China.