Laurentide Ice Sheet Collapse: 14,000 Years Ago

He walks through a 1976 study on Hudson Bay's isostatic rebound, the land rising after ice removal, and what it reveals about the Laurentide Ice Sheet's collapse. The abstract describes an ice unloading model requiring the central dome to have collapsed between 12,000 and 10,000 years before present in radiocarbon years. But here's the critical adjustment: in 1976, researchers were only beginning to revise and calibrate radiocarbon dates. Add the necessary correction, roughly 2,000 years, and the collapse window shifts to between 14,000 and 12,000 years ago. That timing places the event squarely within the Younger Dryas boundary period, when catastrophic meltwater pulses and rapid climate shifts were already underway. The rebound data from the Ottawa Islands doesn't just track uplift. It tracks the speed and scale of ice loss, and the numbers point to something sudden, not gradual.