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 Grand Canyon of Yellowstone

Recently, scientists have recognized volcanic unrest at two calderas in the United States, Long Valley Caldera in eastern California and Yellowstone Caldera in Yellowstone National Park, Wyoming. Whether unrest at these calderas simply punctuates long periods of quiet or is the early warning sign of future eruptions is an important but still unanswered question. Yellowstone River plummets through the famous Grand Canyon of Yellowstone. Carved by the river, the "yellow" rocks of the canyon are rhyolite lava flows that have been altered by hot water. The lava flows were erupted after the most recent caldera-forming eruption about 600,000 years ago.

Maintained by John Watson
Updated 06.24.97

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