Scientists detect molten rock layer hidden under Earth’s tectonic plates

Scientists have discovered a new layer of partly molten rock under the Earth's crust that might help settle a long-standing debate about how tectonic plates move. Researchers had previously identified patches of melt at a similar depth. But a new study led by The University of Texas at Austin revealed for the first time the layer's global extent and its part in plate tectonics. The findings were published in the journal Nature Geoscience. The molten layer is roughly 100 miles below the surface and is part of the asthenosphere, located in the upper mantle beneath the Earth's tectonic plates.