The Columbia River basalts
Fissures in the Pacific Northwest pour out lava flows that individually cover the area of a small country.
- When
- —
- Duration
- 1.7 million years
- Known to
- ± 300 thousand years
- Era
- Miocene, Cenozoic
Beginning about 16.7 million years ago, more than 350 flows erupt from long fissures in Oregon, Washington and Idaho, burying 200,000 square kilometres to depths of up to 1.8 kilometres. Individual flows travel over 500 kilometres to the sea. It is the youngest large igneous province on Earth and therefore the best preserved, which makes it the reference case for understanding how flood basalts erupt — and, by extension, how the far larger Deccan and Siberian events that accompanied mass extinctions worked.