Tag Archives: plate boundary

Geologists Correct a Rift in Africa

EAST LANSING, Mich. — The huge changes in the Earth’s crust that influenced human evolution are being redefined, according to research published today in Nature Geoscience.

The Great Rift Valley of East Africa – the birthplace of the human species – may have taken much longer to develop than previously believed.

“We now believe that the western portion of the rift formed about 25 million years ago, and is approximately as old as the eastern part, instead of much younger as other studies have maintained,” said Michael Gottfried, Michigan State University associate professor of geological sciences. “The significance is that the Rift Valley is the setting for the most crucial steps in primate and ultimately human evolution, and our study has major implications for the environmental and landscape changes that form the backdrop for that evolutionary story.” (more…)

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New Understanding of Earth’s Mantle Beneath The Pacific Ocean

Washington, D.C. — Scientists have long speculated about why there is a large change in the strength of rocks that lie at the boundary between two layers immediately under Earth’s crust: the lithosphere and underlying asthenosphere. Understanding this boundary is central to our knowledge of plate tectonics and thus the formation and evolution of our planet as we know it today. A new technique for observing this transition, particularly in the portion of Earth’s mantle that lies beneath the Pacific Ocean basin, has led Carnegie and NASA Goddard scientist Nick Schmerr to new insight on the origins of the lithosphere and asthenosphere. His work is published March 23 in Science. (more…)

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Scientists Study Earthquake Triggers in Pacific Ocean

*Samples of rock, sediment from beneath the sea-floor help explain quakes like Japan’s*

New samples of rock and sediment from the depths of the eastern Pacific Ocean may help explain the cause of large, destructive earthquakes similar to the Tohoku Earthquake that struck Japan in mid-March.

Nearly 1,500 meters (almost one mile) of sediment cores collected from the ocean floor off the coast of Costa Rica reveal detailed records of some two million years of tectonic activity along a seismic plate boundary. (more…)

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