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Columbia River Flood Basalts

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Over 40,000 cubic miles of basaltic lava, known as the Columbia River Flood Basalts, covers parts of Washington, Oregon, and Idaho.

These tremendous lava flows erupted between 17 and 6 million years ago. Over 300 high-volume individual lava flows have been identified, along with countless smaller flows.

The slightly depressed lava plain is now known as the Columbia Plateau.



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