Mark H. Thiemens

Thiemens moved to the Department of Chemistry at the University of California San Diego in 1980, where he was hired as an assistant professor as a replacement for Hans Seuss and took over the laboratory of Nobel Laureate Harold Urey. He was promoted to Full Professor in 1989, and served as the Chair of the Department of Chemistry and Biochemistry from 1996-1999. He was the founding Dean of the Division of Physical Sciences and served from 1999-2016.

Thiemens earned his bachelor of Science degree from the University of Miami. His studies with isotope geochemist Cesare Emiliani, PhD student of Harold Urey and a co-discoverer of paleoclimate temperature determination stimulated his interests in isotopes. Thiemens received a MS from Old Dominion University and PhD from Florida State University for his research using stable isotopes and particle identification using the FSU Van de Graff accelerator. He moved to the University of Chicago at the Enrico Fermi Institute for Nuclear Studies (1977-1980) where he worked with Robert N. Clayton using lunar samples to track solar wind origin and evolution, meteorite cosmochemistry, and early atmospheric chemistry.

Mark Howard Thiemens (born January 6, 1950 in St. Louis, Missouri) is a Distinguished Professor and the Chancellors Associates Chair in the Department of Chemistry and Biochemistry at the University of California San Diego. He is best known for the discovery of a new physical chemical phenomena termed the mass independent isotope effect.