Black Hills National Forest Lode and Placer Gold Geology: Wyoming and South Dakota

The geology of the Black Hills National Forest is dominated by exposures of Precambrian rocks following erosion of the Paleozoic, Mesozoic, and Cenozoic sequences that were domed up from granitic intrusions and later eroded. Proterozoic plutonism metamorphosed and deformed many of the Precambrian rocks along with fault development. During these intrusive processes, gold deposits and associated mineralization occurred under several different types of emplacement. In addition to lode gold emplacement, erosion stripped many of the primary gold into placer gold deposits during Phanerozoic time. Three chapters are included to describe the geology of lode and placer gold in the Black Hills National Forest.

Chapter 1 provides an introduction to the Black Hills geology. Chapter 2 presents Black Hills deposits mostly as lode gold deposits. Chapter 3 presents geomorphic descriptions of placer gold deposits and where they might be found.