Gold in the Black Hills, South Dakota, and how new deposits might be found

Precambrian basement map of the Trans-Hudson orogen and adjacent terranes, northern Great Plains, U.S.A.

“…Lead isotope data indicate that the lead came from a 2.5 Ga source and went through metamorphism and remobilization at 1.6 Ga, concurrent with the Central Plains orogeny. In the search for new gold deposits, Norton (1974) suggested that carbonate-facies iron-formation at the garnet isograd state of metamorphism provides the most favorable environment.…”

Mineral resources; potentials and problems

“…Department of Interior, 1973, 1974. The estimates of identified subeconomic, hypothetical, and speculative resources, and discussions of their problems, are based on the commodity chapters of Brobst and Pratt (1973).…”

“…The same rocks and structures that contain the Homestake deposit continue underneath the younger rocks, and J. J. Norton (1974) has recently proposed testing of the hypothesis that another Homestake-type deposit might be discovered by carefully planned exploration of the buried Precambrian rocks. Total recorded production of the Homestake mine to date is more than 35 million oz.…”

Structural geology and tectonics of the paleoproterozoic rocks of the Mount Rushmore Quadangle, Black Hills, Souh Dakota

“…Most notably, they pointed out that rocks "of Oreville lithology" in the northeast corner of the quadrangle (across the Empire Mine-Keystone fault system) were not necessarily correlative with Oreville-type rocks elsewhere in quadrangle. Norton (1974) correlated the Oreville formation with the Swede Gulch Formation of Bayley (1972) and then correlated the Swede Gulch with the Grizzly Formation of Noble and Harder (1948).…”

“…Redden (1963Redden ( , 1968 Previous workers raised concerns about correlating rocks across multiple faults based solely on lithologic similarity (e.g. Ratte and Wayland, 1969;Norton, 1974;Woodland, 1979;Ratte, 1986). Appendix B summarizes some of the major inconsistencies with previous stratigraphic correlations and their application to ascertaining the regional structure.…”