Lithium element enrichment and inspiration of the prospecting for rare-metal mineralization at the Dahutang tungsten deposit: constraints from mineralogy and geochemistry of the hydrothermal alteration
Abstract:In recent years, a series of rare metals and tungsten prospecting breakthroughs have made in the northwestern Jiangxi. Especially, the Li-Rb enrichment and mineralization is for the first time reported at the Dahutang giant tungsten deposit. It shows an obvious distinction, probably a genetic relationship between the W and Li-Rb deposit. The Dahutang tungsten deposit have a characteristic of low grade, high tonnage, and strongly hydrothermal alteration. Basin on the identification of mineralogy of Li-mica and hydrothermal alteration type. The hydrothermal Li-mica were zinnwaldite (Li2O=4.15%～4.86%), protolithionite (Li2O=0.81%～1.72%), and Li-phengite (Li2O=0.24%～0.45%). We chose 47 altered hand specimen for whole rock geochemistry analysis. Research shows lithium mineralization mostly for the enrichment of Li-mica at the Dahutang tungsten deposit. The protolithionite and zinnwaldite altered Neoproterozoic granodiorite sample have a characteristic of highly concentrated of K2O (5.94%～8.06%), (Li2O=0.34%～1.548%) and Rb2O (0.175%～0.784%). However, the trilithionite, paragonite and albite Yanshanian altered porphyritic biotite granite have a characteristic of highly concentrated of Na2O (5.79%～6.17%)，Li2O (0.902%～1.034%), and Rb2O (0.140%～0.213%). Significantly, the unaltered Yanshanian granite have a characteristic of multi-phase magmatic activity, but all enriched in Li, Rb, and W. Potentially, further enrichment and mineralization due to the hydrothermal fluid circulation. This work demonstrate a precipitation sequence from the magmatic Nb-Ta mineralization to Li-Rb, and then the W-Mo hydrothermal deposit. Preliminary study could be conducive to a new direction for the regional and deep prospecting of rare metals in the tungsten deposit at the northwestern Jiangxi.