Day One - Papers
Auriferous quartz veins cut Lower Proterozoic metasedimentary strata at a number of localities in the Black Hills (Paterson et al., 1988). The majority of these occurrences are in metamorphosed graywaeke, with some occurrences in metamorphosed shale. Many veins occur in metamorphic rocks of relatively low metamoiphic grade (garnet zone or lower) that are far removed from known intrusions of granitic rocks, and a metamorphic origin for the fluids and gold seems probable (e.g., Henley et al., 1976; Kerrich and Fryer, 1979; Paterson, 1986). For other veins, in higher-grade metamorphic rocks that are associated with numerous intrusions of Harney Peak Granite and pegmatites, the origin of the vein-forming fluids and gold is more ambiguous, and both metamorphic and magmatic components must be considered.
The purpose of this review is to summarize results of fluid inclusion studies on some of the gold-quartz veins in metamorphic rocks in the central Black Hills. The ten veins considered in this report range from the lower garnet zone through the sillimanite zone (Fig. 1). Fluid inclusion results are examined with reference to variations in host rock lithology and metamorphic grade, and with respect to proximity of the veins to exposed bodies of granite and pegmatite.