The Yellowstone hotspot starts its track
A line of dead calderas across Idaho records North America sliding southwest over a fixed plume.
- When
- —
- Duration
- 11 million years
- Known to
- ± 500 thousand years
- Era
- Miocene, Cenozoic
The same mantle upwelling that fed the Columbia River basalts begins producing enormous rhyolitic caldera eruptions from about 16.5 million years ago. Because the plume stays roughly fixed while the North American plate moves southwest, the eruptions leave a track of successively younger calderas along the Snake River Plain, ending at Yellowstone. The plain is a scar 700 kilometres long, and reading it backwards gives both the plate's motion and a repeating record of supereruptions.