WollongongUp to 1 billion years of rock are missing in the Grand Canyon.
Glaciers alone cannot explain why the gap is obvious in North America but not everywhere.
Five of 6 mantle simulations lifted North America for hundreds of millions of years, until glaciers scoured it and Cambrian seas buried the scar.
University of Wollongong geoscientist Nicolas Flament suspects an older unconformity from a glaciation 2.4 billion years ago, but those rocks lack fossils to date it.
How each outlet framed it
- Ars Technica
- attributes the Great Unconformity to deep mantle currents that pushed continents up for hundreds of millions of years, not just surface erosion
Sources: Ars Technica