Understanding the composition, structure and evolution of the Earth and the other terrestrial planets are dominant themes of my research. The differentiation of the Earth has created 3 highly stratified and distinct reservoirs (i.e., the core, the mantle-crust system, and the atmosphere-hydrosphere system). These reservoirs are in turn themselves internally differentiated. Chemical and isotopic studies of terrestrial and extra-terrestrial samples provide insights into the timing and details of the differentiation of these reservoirs. In addition to developing models for the compositions of the bulk Earth, core and silicate Earth, I use plasma mass spectrometry to analyze samples for their chemical and isotopic compositions. Data from these mass spectrometers are used to improve our understanding of the processes involved in differentiation and the timing of these events.
Since coming to the University of Maryland in 2000 I, together with Claude Dalpe and Richard Ash, have built a state of the art mass spectrometry laboratory. This lab houses 2 inductively coupled plasma-mass spectrometers (ICP-MS) and 2 deep-UV laser ablation systems. Some of my research involves the development of instrumentation and applications. In our ICP-MS laboratory we have analyzed a wide range of materials for their chemical and isotopic compositions, including such diverse samples as: