Fluid-inclusion and trace-element analyses of some barite-fluorite deposits in south-central New Mexico

Fluid inclusions in fluorite collected from barite–fluorite (± galena) deposits in south-central New Mexico show they formed from fluids of similar temperatures and variable salinities. Deposits spatially associated with igneous rocks show salinities of less than 1.5 equivalent wt% NaCI, while those not obviously associated with igneous activity range from almost fresh water (0.1%) to 8%. Homogenization temperatures on all types ranged from 120 to 218°C, with most measurements falling between 140 and 180°C.

Trace-element analysis of barite showed considerable variation in samples from the same localities and no pattern was detected. The Y–Sr ratio in fluorite appears to separate igneous-associated deposits (e.g. Chise district) from sedimentary–hydrothermal deposits (e.g. Hansonburg district). The ratio is less than 1.5 in igneousassociated deposits and greater than 3 in known sedimentary–hydrothermal deposits.