GEOPHYSICS:
Mapping Mantle Melting
Roger Buck
Most of Earth's volume is silicate mantle, hidden from view by a layer of surface crust. A large geophysical experimental collaboration called MELT (mantle electromagnetic and tomography) has in recent years sought to detect and map a region of mantle partial melting to better understand its behavior. As Buck discusses in his Perspective, Evans et al. report in the same issue results from the latest phase of the MELT study. Seismic and electromagnetic data indicate the presence of a small amount of melt over a region several hundred kilometers wide and more than 100 km deep under the East Pacific Rise. The findings run counter to the current picture of the mantle flow and should spur attempts to refine the present models of mantle flow.
The author is in the Department of Earth and Environmental Sciences and the Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, USA. E-mail: buck{at}ldeo.columbia.edu