Characteristics and Geological Significance of CO2-Rich Fluid Inclusions in Dakalasu No. 1 Pegmatite Dyke, Altay

The fluids in of pegmatite rare metal deposits are generally rich elements and volatiles (B, P, F, H2O, CO2, etc.), they have a high capacity for dissolving migrating metals. Dakalasu No. 1 vein is located northwest China’s Altay orogenic belt. Previous studies indicated that it small- to medium-sized beryllium-niobium-tantalum deposit. It showed significant mineral assemblage zonations from the rim core, mineralizing define volatile-rich NaCl-H2O-CO2 ± CH4 system. In this contribution, beryl quartz, which widely developed each association textural zone, were selected fluid inclusion research through detailed petrographic investigation, microthermometry, LA-ICP-MS analysis. Petrographic results show at least three types inclusions zone. They CO2-rich (type I), gas-liquid two-phase II), daughter mineral-bearing III), respectively. Additionally, minor melt IV) visible Microthermometric measurements homogenization temperature zone was concentrated between 242 °C 293 °C, with an average 267 salinity 7.2–10.3 wt% NaCleqv, 8.6 NaCleqv. comparison, core range 225–278 246 focused 6.0–7.7 7.1 quantitative analysis individual by revealed Li, B, K, Zn, Rb, Sb, Cs, As relatively enriched contrast, decreasing trend trace such as Cs. CO2 content exhibited same indicating volatile components played essential role migration enrichment elements. melt-fluid immiscibility likely be necessary mechanism significantly enriching metals dyke.