This project is to continue the study of partitioning of trace elements between minerals and hydrothermal fluids. How do hydrothermal fluids acquire trace elements and become ore-forming fluids? The investigators have recently developed a thermodynamic basis for the partitioning of F and Cl that enables, for the first time, chemical analyses of micas and apatites to be used to place constraints on the pH and the F and Cl contents and speciation of hydrothermal fluids. They expect to expand the applications to (1) Evaluate the pHs of hydrothermal sedimentary basinal and geothermal fluids; (2) study the origins of F enrichment in Mississippi Valley-type ore deposits; and (3) extend the study of partitioning to include the trace alkalis and alkaline earths, by using published experimental studies to calibrate thermodynamic calculations of partitioning of Li, Rb, Cs, Sr, and Ba between micas, feldspars and hydrothermal fluids. The results could have a significant impact upon our understanding of ores develop from hydrothermal solutions.
