James Bischoff (1940-2021)

March 23, 2023

It is with great sadness that we announce the passing of Jim Bischoff who died at the age of 80 on February 17, 2021. Jim had battled several serious illnesses over the past couple of decades and finally succumbed while in the care of hospice with his family at his side. He is survived by his wife Marybeth, children Matthew and Lorena, and four grandchildren.

His curiosity driven life in the pursuit of science led him to a highly successful career in marine geochemistry. Recognizing the impracticality of a fantasy career in archaeology Jim obtained an undergraduate degree in geology at Occidental College and PhD in geochemistry at Berkeley in 1966 under Bill Fyfe. He carried out a two-year postdoc at Woods Hole during a time of great excitement about new discoveries in the oceans, especially about this outrageous new idea of seafloor spreading. After five years as Professor at University of Southern California, Jim joined the Branch of Pacific and Coastal Marine Geology of the USGS in 1974. He quickly built the marine geochemistry program to international acclaim.

Jim was one of those truly outstanding scientists whose pioneering research produced major breakthroughs and fundamental contributions in a multitude of diverse areas, including the geochemistry of diagenetic reactions in sediments and interstitial waters, seafloor geothermal systems and metalliferous deposits, hydrothermal ore deposits, the physical chemistry of supercritical fluids, the geochemistry of lakes and lake deposits, climate change in the western US and chronology of human evolution.

For example, his studies of the mineralogy and chemical composition of metalliferous muds from the Red Sea documented the first ever observation of the formation of a massive sulfide deposit, a discovery that revolutionized our understanding of the nature and origin of these deposits.

In his early days with the USGS, contrary to prevailing wisdom, Jim had postulated that the circulation of seawater and interaction with basalt at high temperature could produce the newly discovered hydrothermal deposits found at seafloor spreading centers. The results of his experiments in a unique newly constructed lab demonstrated that indeed those reactions could produce not only the metalliferous deposits but also the fluid acidity and Mg depletion long missing from the geochemical balance of ocean chemistry. Jim successfully predicted the chemistry of the famous black smokers four years before they were finally discovered and sampled!

The discovery of phase-separated hydrothermal fluids led Jim to a ten year collaboration with the renowned Berkeley professor Kenneth Pitzer on the development of equations-of-state for water-salt systems and exploration of the fundamental vapor-liquid relations in Na-Ca-Cl solutions corresponding to sub-seafloor conditions. His experimental results are directly applicable to the seafloor systems, but also have broad application to hydrothermal processes in general, and provide a crucial experimental basis for theoretical modeling of ionic solutions that is being used extensively by physical chemists.

Jim even melded his long-held interest in archeology with paleoclimate studies by developing entirely new, innovative techniques for dating evaporites, carbonates, bone and tooth enamel by utilizing U-series isotopes. In one instance his chronology for Searles Dry Lake, CA, published in Science and developed by dating a deep sediment core, demonstrated that in contrast to expectations from marine climatic cycles the lake was full during the last interglacial. In another Science article, Jim showed that the controversial Del Mar skeleton, discovered near San Diego, with a claimed age of 48,000 years, was in fact less than 10,000 years old. Nature Magazine highlighted as a major discovery another of Jim's studies of rock shelters in Europe that showed that the Neanderthals had been abruptly replaced by modern humans at 40,000 years ago. This study dislodged the widely held opinion that the transition was evolutionary.

Jim was one of the principal investigators for the deep drilling program at Owens Lake, California, which successfully recovered a 350 meter core, representing a continuous climate record of the past 800 kyrs. Jim applied classical geochemical methods to develop measures of both the amount of rock flour from Sierra Nevada glaciers, and the climatically controlled salinity of the lake itself. He convincingly inferred the sequence, duration, and relative sizes of glacial advances, punctuated by interglacials of warm and saline conditions. This was a significant new step in unraveling continental climate variations. In total, Jim authored or coauthored 375 publications. And In 1999, Jim received the prestigious V. M. Goldschmidt Award given for major achievements in geochemistry.

After retiring as a Senior Scientist (ST) Jim continued studies of Quaternary climate variations in the western U.S. and of paleoanthropology, and even launched a new experimental thrust aimed at establishing the chemical fundamentals of the hypothesized seafloor hydrothermal origin of life. We are saddened at our loss but celebrate his life and his many significant scientific contributions and accomplishments. Jim had many successes in science and in life. His love of science was exceeded only by his devotion to family.

Bob Rosenbauer/Yousif Kharaka/Pat Shanks (USGS)

Category: In Memoriam