The proposed Underground Science Laboratory at the Homestake Mine, Lead, South Dakota, provides an important opportunity to advance geochemical research on several important topics. The planned laboratory has two main advantages for geochemical research. First, and most importantly, it is a controlled, though still natural, environment that can be sampled at a multitude of scales in both time and space. Scales of variability and durations of processes are poorly known in geochemistry, particularly in systems involving natural waters. This limits our ability to extrapolate results from the laboratory to larger, natural scales and this, in turn, limits our ability to use laboratory results to benefit society. The second tremendously important advantage of the laboratory is the large number and wide variety of scientists that will focus on the problems. This will allow almost unparalleled cooperation among geochemists, microbiologists, hydrologists and engineers. This sort of cross-fertilization is required for us to solve problems involving movement and fate of fluid flow in the crust, which is on the most important factors governing the quality of our environment and water supplies.

The main areas in which geochemical research might be focused are environmental geochemistry and mineralogy, stable and radiogenic isotope geochemistry and regional and ore deposit geology and geochemistry. Research in environmental geochemistry and mineralogy will focus on acid mine drainage and other processes that control the chemical interaction of rocks and waters that pass through them. These processes are fundamentally important to water quality and supplies. Investigations in isotope geochemistry will focus on a range of problems important to the dissolution and transport of solutes in water and by offering a way of labeling microbial materials, it will be the main bridge between geochemistry and microbiology. Studies on the regional and ore deposit geology in the Homestake area take advantage of the large vertical extent of the underground mine and the opportunity that it offers for us to study changes at all scales in the upper crust. For more information on research projects that have been proposed, consult the geochemical research plan.

Geochemistry Research at the National Underground Science Laboratory