| Abundant fluorite mineralization in Rio Grande Rift (RGR) barite-fluorite-galena deposits is anomalous compared to typical Mississippi valley type deposits to which they have been compared, and the source of the fluorine in these deposits is controversial.;In this study we used chlorine isotopes to test the possibility of an asthenospheric source of fluorine in the RGR deposits. Chlorine was used as proxy for determining the source of the fluorine because chlorine, unlike fluorine, has more than one isotope and thus can be used as an isotopic tracer. Chlorine and fluorine exhibit chemically similar behavior, and therefore are likely to be derived from the same source if associated with rift related magmatism. Complimentary to chlorine isotopic studies, Br/Cl ratios were also measured from the fluorite fluid inclusions and applied as additional tracers. Sr and Nd isotopes were measured from fluorites, granites, carbonates, and asthenospheric basalts to aid in understanding the petrogenesis of RGR deposits. |
