Evolution of the North American craton

In deep time, Earth remains thermochronologically underexplored. The geologic records that we do have could reflect significant preservation bias and for such older terranes we have often framed questions in terms of "events" rather than processes. In this context, thermochronology has great promise for revealing previously unknown aspects of Earth system evolution. The Neoproterozoic Era extending from 1000 to 540 million years ago encompassed a number of significant changes in Earth’s systems, including major diversification and complexification of the biosphere, episodes of nearly planetary-scale glaciation, and breakup of the supercontinent Rodinia. Studies from North America suggest that this time interval also saw a period of surprisingly robust erosional exhumation of several kilometers, within the interior craton, traditionally thought of as stable and quiescent. Such exhumation could be a key link in connecting Earth-system processes, if it were widespread enough in extent, significant enough in magnitude, and had the correct timing. Depending on details of their thermal histories and crustal temperatures, these cratonic rocks then must have experienced ~3–8 km of exhumation, only some of it happening in the Phanerozoic. This adds to recent thermochronological work that documents significant amounts of exhumation associated with the formation of the extensive Great Unconformity that resulted in widespread Neoproterozoic erosional exhumation post–1 Ga; processes that (1) must reflect a linked geodynamic cause, and (2) may be linked to Snowball Earth glaciations, the global carbon cycle, and the rise of biotic complexity.