by Playfuls Staff |
7th December 2006
U.S. seismologists say they have directly measured, for the first time, the heat flowing from the Earth's [more] molten core into an area at the mantle's base.
The scientists say that flow helps drive both the movement of tectonic plates at the Earth's surface, as well as the geodynamo in the core that generates Earth's magnetic field.
The boundary between the core and the mantle is halfway to the center of the Earth, at a depth of 1,740 miles. The new temperature measurements were obtained by relating seismic observations to a recently discovered mineral transformation that occurs at the ultrahigh pressures and temperatures prevailing near the core-mantle boundary.
"This is the first time we've had a 'thermometer' that tells us the temperature halfway down to the center of the Earth," said University of California-Santa Cruz Professor Thorne Lay, first author of the paper.
Using 72,000 hours of supercomputing time, the scientists determined the temperature at the upper boundary is about 4,000 degrees Fahrenheit. At the lower end of the boundary the temperature is about 5,800 degrees Fahrenheit.
The study appeared in the Nov. 24 issue of the Science.
© 2006 UPI
