In the first experiments able to mimic the crushing, searing conditions found in Earth's lower mantle, and simultaneously probe tell-tale properties of iron,
scientists have discovered that material there behaves very differently than predicted by models. The research also points to the likelihood of a new zone deep in the Earth. The work is published in the September 21, 2007, issue of
Science.
Surface phenomena such as volcanoes and earthquakes are generated by what goes on in Earth's interior. To understand some of these surface dynamics, scientists have to probe deep into the planet. The lower mantle is between 400 and 1,740 miles deep (650 km- 2,800 km) and sits atop the outer core.
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| ©Russell Hemley
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| As depth increases in the planet, so does the temperature and pressure. In this diagram the crust and upper mantle is grey, the lower mantle is yellow, the outer is core orange, and the inner core is bright orange. The pressure between the upper and lower mantle is about 23 gigapascals or about 230,000 times atmospheric pressure at sea level. At the base of the lower mantle the pressure increases to an intense 1.35 million times sea-level pressure (135 GPa).
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