James L. Bischoff is Geochemist Emeritus at the U.S. Geological Survey (since 2002) and, over his career of 40 years, has specialized in several fields; the geochemistry of marine and lacustrine sediments, seafloor geothermal systems, hydrothermal ore deposits, climate change, and chronology of human evolution. At UC Berkeley, he studied the kinetics of the aragonite-calcite transition. At Woods Hole Oceanographic Institution and later at the University of Southern California, he made contributions in carbonate diagenesis, lunar geochemistry, pore-water chemistry, the Red Sea Geothermal system, and the plate tectonics of the Gulf of California. At hyper- saline Mono Lake, California, he studied the mineral paragenesis of the exotic carbonate minerals ikaiite and gaylussite, determining, for the first time, the thermodynamic properties of the former.
In his years at the USGS Jim built an experimental laboratory for the study of seawater-rock interaction it high temperature and pressure. During these years his studies brought to light the specific reactions that produced the acidity and metal transport in seafloor geothermal systems. The co-existence of dissolved sulfide with abundant heavy metals in seawater-basalt experiments led to the prediction of massive sulfide deposits at seafloor discharge sites of the heated seawater. Stimulated in part by the results of these experiments, various institutes launched expeditions to test these ideas. In 1979, four years after publication of these first experimental results, the famous black smokers and massive sulfides were discovered at 21°N EPR by an expedition using the research submersible Alvin. The compositions of seafloor vent fluids are very similar to the fluids produced in the experiments. For this work Jim was awarded the Victor Moritz Goldschmidt Medal by the Geochemical Society of America in 1999.