Laurentia: Turning Points in the Evolution of a Continent
CONTAINS OPEN ACCESS
The North American continent has a rich record of the tectonic environments and processes that occur throughout much of Earth history. This Memoir focuses on seven “turning points” that had specific and lasting impacts on the evolution of Laurentia: (1) The Neoarchean, characterized by cratonization; (2) the Paleoproterozoic and the initial assembly of Laurentia; (3) the Mesoproterozoic southern margin of Laurentia; (4) the Midcontinent rift and the Grenville orogeny; (5) the Neoproterozoic breakup of Rodinia; (6) the mid-Paleozoic phases of the Appalachian-Caledonian orogen; and (7) the Jurassic–Paleogene assembly of the North American Cordillera. The chapters in this Memoir provide syntheses of current understanding of the geologic evolution of Laurentia and North America, as well as new hypotheses for testing.
The Neoarchean, a turning point for geodynamic and magmatic processes within the Superior craton?
Published:January 23, 2023
Lucie Mathieu*, David Mole, Zsuzsanna Tóth, Kate Rubingh, Rasmus Haugaard, Shawna White, Chong Ma, Ben Frieman, Robert Lodge, Ross Sherlock, Bruno Lafrance, 2023. "The Neoarchean, a turning point for geodynamic and magmatic processes within the Superior craton?", Laurentia: Turning Points in the Evolution of a Continent, Steven J. Whitmeyer, Michael L. Williams, Dawn A. Kellett, Basil Tikoff
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The Neoarchean is generally considered to have been the final era of major crust formation and may have been characterized by the onset of modern plate tectonics. The Neoarchean may also have been the time interval during which subduction processes prevailed and became global. Evidence from individual cratons around the world suggests that this transition in geodynamic processes may have included diachronous and episodic major changes (i.e., turning points) and a more gradual evolution at the global scale, possibly largely driven by the secular cooling of the mantle and increasing stability of the lithosphere. The Superior craton, Canada, is the largest and best-preserved Archean craton in the world, making it an ideal location in which to investigate the occurrence (or absence) of turning points in the Neoarchean. This contribution examines the changes in geodynamic and magmatic processes that occurred during the Neoarchean, using geochemical data and new insights garnered from isotopic surveys from the southern part of the Superior craton. We summarize current understanding of the evolution of the youngest (southern) part of the Superior craton that led to the stabilization (cratonization) of this continental lithosphere and how this evolution aligns with local and global geodynamic processes.