John Grotzinger
Grotzinger's lab has shown how Precambrian carbonate rocks reflect Earth's early tectonic environmental and biological evolution. Their investigations in Siberia, Namibia, and now Oman have established the time frame and environmental circumstances of early animal diversification.

Research Interests: I am a field geologist interested in the evolution of Earth's surficial environments and biosphere. My research addresses the chemical development of the early oceans and atmosphere, the environmental context of early animal evolution, and the geologic factors that regulate sedimentary basins. I have worked on establishing the basic geologic framework of a number of sedimentary basins and orogenic belts in northwest Canada, northern Siberia, southern Africa, and the western United States. These field mapping studies are the starting point for more topical laboratory-based studies involving geochemical, paleontological, and geochronological techniques. Currently, my research is focused on the reconstruction of environmental conditions associated with the Cambrian radiation of animals. Work in Oman, Namibia, and Siberia suggests that radiation of Cambrian animals may have coincided with extinction of Precambrian animals, brought on by an episode of global ocean anoxia. Other research involves simulation of stromatolite morphogenesis and the evaluation of the role of microorganisms in stromatolite growth.