Albrecht W. Hofmann, Max Planck Institute for Chemistry in Mainz, Germany
Recipient of the 2015 Urey Award
Albrecht “Al” Hofmann is Emeritus Director of the Geochemistry Division of the Max Planck Institute for Chemistry in Mainz, Germany. Currently, he is also Adjunct Professor and Visiting Senior Research Scientist at Lamont-Doherty Earth Observatory, Columbia University, New York, Adjunct Professor at the University of Nanjing, China, and Guest Professor at the China University of Geosciences in Wuhan, China.
Research Statement
“After an early focus on geochronology and diffusion kinetics my interests shifted toward isotope and trace element geochemistry of Earth’s mantle and to questions of crust-mantle evolution. Together with Bill White, I embraced Jason Morgan’s mantle plume hypothesis as a mechanism to recycle subducted ocean crust and thereby explain the geochemical differences between ocean island basalts and mid-ocean ridge basalts. Later, I teamed up with mantle dynamicists Uli Christensen and Cinzia Farnetani, and with Alex Sobolev, to interpret specific geochemical heterogeneities seen in hotspot volcanism. In the dynamical models, the thermal boundary layer at the base of the mantle plays a key role as a place where former ocean crust is segregated and stored and ultimately re-entrained by rising plumes. In the work with Sobolev, we use melt inclusions to identify specific lithologies such as recycled pyroxenites in basalt sources.
As our ability to analyze a wide range of highly incompatible elements in mantle-derived basalts developed since the 1980s, starting with spark source mass spectrometry and continuing with ICPMS technology, our team at the Mainz MPI, with the analytical support of Klaus Peter Jochum, identified a series of specific trace element ratios, now called “canonical”, which show little or no systematic changes over absolute concentration ranges of up to three orders of magnitude in basalts. Thus, canonical ratios reflect the respective source ratios, some of which, notably (Nb,Ta)/(Th,U) and Pb/(Ce, Pr), are highly useful tracers of continental/arc-related versus normal-mantle related sources. Together with isotope ratios, such canonical trace element ratios help us trace the long-term evolution of the crust-mantle system.”
Also see Albrecht W. Hofmann’s Curriculum Vitae, list of publications and Google Scholar page.