The Hansonburg, New Mexico district in the southwestern U.S.A. contains anomalously fluorite rich carbonate-hosted base metal sulfide deposits. A long-standing hypothesis for this fluorite enrichment is that the Hansonburg mineralizing fluids were correspondingly enriched in F relative to the typical sedimentary brines that formed carbonate-hosted base metal deposits.

The purpose of the present study was to test this hypothesis by determining the F concentration in fluid inclusions hosted by drusy quartz that paragenetically overlaps fluorite. The fluid inclusions were thermally decrepitated creating evaporative solute mounds, which were then analyzed via scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS). Fluorine was detected in all evaporative solute mounds analyzed, equating to fluid inclusion F concentrations of 320 to 2500 ppm. These F concentrations are significantly greater than the F concentrations of tenth's to 10s of ppm F typical of sedimentary brines. Further, these high F concentrations indicate that the Hansonburg mineralizing fluid must have been very acidic during the time of fluorite mineralization with a pH of 1 to 2.4. This pH is much lower than the pH of 4.3 to 5.1 predicted in earlier studies and also much lower than the pH of 4 to 5.5 considered typical of carbonate-hosted ZnPb mineralizing fluids. High mineralizing fluid F concentrations in combination with low pH would have provided conditions favorable for the formation of the observed Hansonburg mineral assemblage, i.e. fluorite-barite rich and metal sulfide mineral poor.

美国西南部的新墨西哥州汉森堡地区含有异常富含萤石的碳酸盐基底金属硫化物矿床。这种萤石富集的长期假设是，相对于形成碳酸盐为主的贱金属矿床的典型沉积卤水，汉森堡矿化流体相应地富集 F。

本研究的目的是通过确定与萤石共生重叠的晶簇石英所包含的流体包裹体中的 F 浓度来检验这一假设。流体包裹体被热爆裂形成蒸发溶质丘，然后通过扫描电子显微镜 - 能量色散 X 射线光谱 (SEM-EDS) 进行分析。在分析的所有蒸发溶质堆中都检测到氟，相当于流体包裹体 F 浓度为 320 至 2500 ppm。这些 F 浓度显着高于沉积卤水典型的 ppm F 的十分之一到 10 几分之一的 F 浓度。此外，这些高 F 浓度表明，Hansonburg 矿化流体在萤石矿化期间一定是非常酸性的，pH 值为 1 到 2.4。该 pH 值远低于 4 的 pH 值。铅矿化液。高矿化流体 F 浓度与低 pH 值相结合将为观察到的汉森堡矿物组合的形成提供有利条件，即富含萤石-重晶石和贫金属硫化物矿物。