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Earth shattering find in Africa

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13.01.2005

The African continent is slowly being pulled apart and new data collected by University of Leeds and Royal Holloway, University of London researchers suggests that molten rock from deep within the Earth is helping the rifting. Their findings, which help explain how continents split apart, are published in Nature this week.

Ethiopia sits on a boundary where a tectonic plate is being split into two and over several million years a new ocean basin is forming. The movement of plates on the Earth’s surface alone does not provide enough force to cause the rift seen in Ethiopia. Measurements of sub-surface waves and geological information show that molten rock - magma - rising through the Earth’s outer layers is reducing the strength of the plate, enabling it to break apart.

Geophysicists led by University of Leeds Professor Michael Kendall studied seismic waves as they passed through the Earth’s upper mantle over a 16 month experiment in Ethiopia. As the waves hit different materials their properties change. The recorded wave patterns indicate the presence of thin sheet-like upwellings of molten rock.

Professor Kendall said: "This is the largest experiment of its kind ever done in Africa. It is revealing answers to long-standing mysteries about continental plates and how they split apart to form new ocean basins.’’

Royal Holloway co-author Professor Cindy Ebinger added: "Scientists have previously proposed that magma may play a significant role in weakening continental plates, but this is the first supporting evidence from an active rift zone.”

Professor Kendall said: "We have found the signature of the melting process throughout the plate. The analysis also confirms the importance of magmatism, not just plate stretching, in creating rifts."

Hannah Love | Source: alphagalileo
Further information: www.leeds.ac.uk
www.nature.com

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