Cryogenian glacial erosion of the central Canadian Shield: The “late” Great Unconformity on thin ice

Abstract The Great Unconformity has been recognized for more than a century, but only recently have its origins become subject of debate. Hypotheses suggest global Snowball Earth glaciations and tectonic processes associated with the supercontinent Rodinia as drivers widespread kilometer-scale erosion in late Neoproterozoic. We present new integrated zircon apatite (U-Th)/He fission-track thermochronology from Precambrian basement samples central Canadian Shield northern Manitoba to test these ideas. Bayesian inverse modeling indicates that 150–200 °C cooling (>3 km exhumation) occurred simultaneously Cryogenian at ca. 690–650 Ma within interior North America. This estimate timing unroofing is precise previous appraisals does not align any known or magmatic events (i.e., large igneous province eruptions) potentially cycle during Proterozoic along Laurentian margins. Based on results interpretations, magnitude exhumation best explained by glacial erosion, further establishes importance multiple thermochronometers resolving detailed deeptime thermal histories.