Isotope Geochemistry and Geochronology

Many of our past isotopic studies involved understanding the tectonic and magmatic evolution of world-wide orogenic belts, ranging in age from Paleoproterozoic to Miocene. Because of the enormous utility of radiogenic isotopes in earth sciences, however, a wide variety of other, non-tectonic based studies were also pursued over the years. These studies include using Sr isotopes as a hydrologic tracer for watersheds (Peru, Wyoming and New York); using Nd and Sr isotopic compositions of phenocrysts as a powerful tephrochronologic tool; determining ancient seawater 87Sr/86Sr to constrain ages of critical Cenozoic stratigraphic sections; using Pb isotopes to help source archeological artifacts; development of new methods for provenance studies (Nd isotopes in detrital monazite); isotopic zonation in apatite to constrain magma mingling models; and using radiogenic isotopes in novel environmental studies (e.g., documenting land fill breaches).