9530019 Maciie This is a three year collaborative proposal for investigating upper mantle (< 1000 km) conductivity differences beneath the oceans and continents. Subcontinental and suboceanic upper mantle compositional and temperature differences have been proposed to explain a wide array of geophysical data (jordan, 1975) and are postulated to play an important role in plate tectonics and mantle convection. This concept, known as the tectosphere concept, envisions that the subcontinental mantle is cold and depleted in iron relative to the suboceanic mantle. Electrical properties in the mantle are strongly dependent upon both temperature and iron, and hence, it is expected that there would be considerable information in the electrical property differences between the suboceanic and subcontinental uppers mantles. The project will involve collections of several field data sets which will be combined into a consistent and robust 3-D model of the upper mantle conductivity structure for a detailed electrical look at the tectosphere concept.
