Formation of the Lened W-(Be) Skarn Deposit by Neutralization of a Magmatic Fluid—Evidence from H3BO3-Rich Fluids

Magmatic-hydrothermal systems, especially those causing the formation of tungsten deposits, may be enriched in boron, as is suggested by presence hydrothermal tourmaline. This study examines boron and metal (including tungsten) concentrations quartz-hosted fluid inclusions Lened W-(Be) deposit Canadian Cordillera resolves (i) analytical challenges involved during salinity calculations B-rich fluids (ii) relationship between chemical composition ore-forming processes at Lened. The aqueous from this have high CO2 contents, indicated a carbonic phase sassolite crystals (H3BO3) inclusions. content liquid (0.5 wt. %) was determined using microthermometric Raman spectroscopic analyses. Boron judged most appropriate internal standard for quantifying LA-ICP-MS data these after calculation H2O-NaCl-H3BO3 system (3.5 to 5 % NaCleq). Trace element show relatively Li (40 474 ppm), Al (56 1003 As (36 490 ppm) Cs (68 296 ppm); lower Rb (3.6 77 Sr (0.4 23 Sb (1 32 Ba (0.6 163 Mg (6.9 7.6 other metals, such Be (2.4 10.2 W 27 Cu (5.1 73 ppm). suggest magmatic origin while moderate are indicative fluid–rock interaction with surrounding limestone. suggests that were highly acidic. neutralization through limestone probable trigger scheelite precipitation. indicates potential role enrichment source melt before exsolution.