Scientists helping to improve knowledge of plate tectonics

Plate tectonics is responsible for diverse geological phenomena including continental drift, mountain building and the occurrence of volcanoes and earthquakes. Scientists at The Australian National University (ANU) are helping to improve understanding of how rocks in Earth's hot, deep interior enable the motions of tectonic plates, which regulate the water cycle that is critical for a habitable planet. Research team leader Professor Ian Jackson said tectonic plates were continuously created at mid-ocean ridges and destroyed when they sink back into the Earth's mantle. "Plate tectonics is responsible for diverse geological phenomena including continental drift, mountain building and the occurrence of volcanoes and earthquakes," said Professor Jackson from the ANU Research School of Earth Sciences. The stirring of the Earth's interior, which is responsible for the plate motions at the surface, has resulted in the Earth's gradual cooling over its 4.5 billion-year life. He said defects allowed the normally strong and hard minerals of the Earth's deep interior to change their shape and flow like viscous fluid on geological timescales. "We have found that flaws in the regular atomic packing in the dominant upper-mantle mineral, called olivine, that become more prevalent under oxidising conditions, substantially reduce the speeds of seismic waves," Professor Jackson said.