Cosmic Journeys - Supervolcanoes

They are eruptions so vast, so Earth-shattering, they have changed the history of our planet. Climate collapse. Toxic turmoil. Mass extinction. Worse than a killer asteroid, or nuclear war, they are Earth s most destructive Supervolcanoes. North America, the time was six hundred and forty thousand years ago, long before humans arrived on the continent. Amid one of nature s great mountain building projects, the Rockies, vast columns of smoke began to rise high into the atmosphere. And soon a smokey haze wrapped the globe. A thick blanket of ashe spread over the western United States. Geologists have traced this event to a depression in the land known as a caldera, in the heart of Yellowstone National Park in Wyoming. Today, we venture to Yellowstone to admire its spectacles of steam and boiling mud. Visitors to Yellowstone may never suspect they are atop one of the world s largest active volcanoes. The last time it blew, it sent an estimated 1000 cubic kilometers of dirt, rocks, ashe, dust, and soot into the atmosphere. But that s small compared to Earth s largest super volcanoes. Find out what made Toba, Siberian Traps, Deccan Traps and other super eruptions so powerful.