Research Overview:

It is likely that supercontinents have come and gone throughout Earth history, but their precise configurations are unknown for the 95% of the geological record that preceded Pangea. Paleomagnetism is the only quantitative method available for reconstruction of continents during this interval. My and my students' research entails fieldwork (on six continents thus far), paleomagnetic analyses, and regional/global tectonic syntheses; together, these constitute the building blocks for reconstructing ancient supercontinents.

These studies provide the paleogeographic framework for all aspects of the long-term Earth system. Most directly, continental assemblies and dispersals manifest first-order patterns in mantle convection and global geodynamics. How far back in time can we see the hallmarks of plate tectonics? Was true polar wander more prevalent during certain epochs? Is there a regular pulse of mantle convection and supercontinental cycles?

More indirectly, continental reconstructions generate important boundary conditions for models of long-term global climate and evolution. Can the paleogeography of late Precambrian time help elucidate the causes of enigmatic low-latitude glacial deposits, and did the planet experience 'Snowball Earth' events? Did extremely rapid continental motions during the Proterozoic-Cambrian transition influence the dramatic appearance of animal phyla at that time?

Finally, paleomagnetism is in itself a fascinating field with numerous applications. Magnetic reversals and superchrons aid understanding of the geodynamo and core-mantle interactions. Paleomagnetic studies have helped to 'date' ore-forming events among world-class economic deposits. Paleo-intensity studies of the Earth's geodynamo can constrain models of planetary evolution. Spatial patterns of chemical remagnetizations yield insights into fluid migration through the crust at a variety of scales. Magnetic polarity stratigraphy can contribute to an integrated study of sedimentary basin analysis, with implications for regional tectonics, the geological timescale, or biological radiation and extinction.