Michael L. Williams
Dept. of Geosciences, University of Massachusetts, Amherst, Massachusetts 01003, USA,
mlw@geo.umass.edu
Dawn A. Kellett
Geological Survey of Canada–Atlantic Division, Natural Resources Canada/Government of
Canada, 1 Challenger Drive, Dartmouth, Nova Scotia B2Y 4A2, Canada, dawn.kellett@canada.ca
Basil Tikoff*
Dept. of Geoscience, University of Wisconsin–Madison, 1215 W. Dayton Street, Madison,
Wisconsin 53706, USA, basil@geology.wisc.edu
Steven J. Whitmeyer
Dept. of Geology and Environmental Science, James Madison University, 801 Carrier
Drive, MSC 6903, Harrisonburg, Virginia 22807, USA, whitmesj@jmu.edu
Abstract
The North American continent records the evolution of tectonic processes and tectonic
environments from the earliest Archean to modern times. The continent hosts a rich Archean (and
possibly Hadean) record, at least three great Proterozoic orogenic belts, and a wide range of
Phanerozoic tectonic, sedimentary, and paleobiologic environments, including active plate
boundaries. In many ways, Laurentia (ancestral North America) might be thought of as the
prototypical continent, with a little—if not a lot—of everything. With its long record of
changing tectonic settings, supercontinent cycles, and geologic outcomes, one question persists:
Does Laurentia preserve a record of fundamental, relatively short duration changes in tectonic
processes on Earth, or rather, a gradually changing configuration of continents in a slowly
evolving plate tectonic system? The resolution of this question requires a continent-wide
perspective on tectonics through time, and it requires the integration of many fields of
geoscience. One way to approach the question is to ask (1) what is the holistic geological
character of Laurentia at particular times in Earth history?; and (2) what are the apparent
controlling factors at those times, from mantle dynamics to plate interactions, to surface
weathering, to biological evolution?
* Corresponding author.
Manuscript received 3 Apr. 2020. Revised manuscript received 15 Apr. 2020.
Manuscript accepted 24 Apr. 2020. Posted 22 May 2020.
https://doi.org/10.1130/GSATG459GW.1
© 2020, The Geological Society of America. CC-BY-NC.