Wandering continents

NASA sicentists have been looking at how continents wander and plate tectonics in general – see www.sciencedaily.com/releases/2012/03/120322161938.htm. A layer of partially molten rock deep underground is thought to be the mechanism that allows continents to wander – or plates. What else might be going on? Seismometer data suggests this layer is patchy – especially under the Pacific Ocean. The molten rock can be found in volcanic regions, for example, and near underwater volcanoes or around subduction zones/plate boundaries but it does not exist everywhere – which took the researchers by surprise. Something other than melted rocks is required to explain the properties of the asthenosphere. This is potentially significant.