Geochemistry and ore-search prospect analysis of the Xiaojiashan tungsten metallogenic rock mass in Barkol area, Xinjiang

Xiaojiashan tungsten deposit is located in East Junggar metallogenic area of Xinjiang and biotite granite is the most widely distributed intrusive rock mass, with alteration diorite and metamorphic crystal tuff being the mainly surrounding rocks.Systematic analyses on geochemical features from major elements, trace elements and rare earth of intrusive rocks and surrounding rock mass in Xiaojiashan reveal nature of faults, sources of ore-forming materials and tectonic settings of intrusive rocks.In the course of alteration, potassium feldspar was decomposed and elements such as W migrated into the vein through granite under the hydrothermal process, making the content of tungsten lower gradually in the alteration of surrounding rocks.The biotite granite is the product of magmatic activities in Hercynian period of Late Paleozoic.Tectonic settings of the deposit are post-collisional extensional granite, and the rocks were formed in an extensional tectonic environment.Under the influence of Hercynian tectonic activities, tungsten-containing granitic magma invaded strata, and magmatic hydrothermal transitional fluid, which was rich in tungsten and flowed upward along the fissure, causing silicification and sericitization in the upper strata.With the increase of atmospheric precipitation, ore-forming fluid temperature was reduced and the ore-forming materials and quartz precipitation formed the quartz vein type tungsten deposit.Combined with the law of mineralization enrichment, ore-controlling fault structures and W content contour lines in anomalous zone, the metallogenic potential in the western periphery and deep part of the mining area was analyzed.