EARTH

The Mountains That Built Rodinia

~1.09 to 0.98 billion years ago

Proterozoic · Mesoproterozoic · Stenian

A range on the scale of the Himalayas once ran from Labrador to Alabama, and its counterparts stand on every other continent. It was thrown up by continents driving into one another, and the collision welded the pieces of Rodinia into a single mass. The peaks were ground away long ago; what is left is their root, the rock that lay deep beneath them, now the bedrock of eastern Canada.

Why it matters

Mountains wear away; the seam where two continents met does not. Rodinia was welded along this line and later tore along much of it, which is how a range that vanished a billion years ago still decides what eastern Canada is built on.

Dating & uncertainty

The collision belt runs three thousand kilometres through eastern North America and has counterparts on every continent, but correlating them is uncertain: which pieces met, and in what order, still varies between reconstructions of Rodinia.

Sources

1. Indares (2025), Canadian Journal of Earth Sciences · The Grenville Province: revisiting the orogenic framework and integrating recent findings
2. Li et al. (2002), Geology · Grenvillian continental collision in south China: new SHRIMP U-Pb zircon results and implications for the configuration of Rodinia
3. Johnson et al. (2020), Precambrian Research · Tectonic evolution of the Grenville Orogen in the central Appalachians

Earth history as one day

18:14:165 h 46 min before midnight

if Earth’s 4.54 billion years were compressed into a single day