Dr. Elizabeth Cottrell is chair of the Department of Mineral Sciences at the Smithsonian’s National Museum of Natural History in Washington, DC.
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11:15
‘Time Capsule’ Rocks Provide Clues About Earth’s Mantle
Samples of 2.5 billion-year-old mantle rocks found at spreading ocean ridges could put bounds on models of how the planet formed.
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23:48
Keeping an Eye on Eruptions Around the World
At least 20 volcanoes are probably erupting as you read these words.