The Chemical Characteristics and Metallogenic Mechanism of Beryl from Cuonadong Sn-W-Be Rare Polymetallic Deposit in Southern Tibet, China

The Cuonadong deposit is the first large scale Sn-W-Be rare polymetallic located in southern Tibet, China, where beryl main beryllium-bearing mineral. In this paper, crystals pegmatitic and hydrothermal vein orebody from Xianglin area of are research objects, marked as Beryl-I Beryl-II, they investigated by EPMA, LA-ICP-MS situ micro-X-ray diffraction (XRD). Data EPMA reveal that beryls alkaline beryls, among which composed Li-Cs beryl, Beryl-II Na Na-Li indicating have undergone noticeable alkali metasomatism during formation. Cs/Na ratio ranges 0.10 to 0.44, Mg/Fe almost 0, showing formed under high-differentiation evolution conditions rarely affected transformation, whereas 2.73 17.31, nearly has been obviously late metasomatism. XRD analysis shows both t-beryl, c/a (1.0010–1.0012) slightly higher than (1.0005–1.0008), may also reflect transition magmatism stage magmatism. Based on comprehensive analysis, we believe precipitation mainly caused emplacement highly fractionated magma containing Be top rock mass or surrounding rock, melt-fluid undercooling, crystallization volatile-bearing minerals (such tourmaline fluorite). Moreover, Be-bearing ore-forming fluid further migrated upward along near north–south faults middle Miocene (16–15 Ma), precipitates owing water mixing, cooling, amounts (mainly Therefore, it can be concluded mineralization largely reflects process magmatic–hydrothermal mineralization. Because a number mineralized areas with similar metallogenic backgrounds Himalayan region, great potential new globally significant metal belt.