The floor of the ocean doesn’t get that much attention, but when it does the deep sea is often portrayed as an endless expanse of deep, smooth ocean floor inhabited by giant squids. Instead, ship and satellite geophysical data reveal steep cliffs and valleys over vast areas, sometimes over 3 kilometers in elevation. Other parts of the ocean floor are dead flat.
Ocean basins cover 70% of the Earth’s surface. What forces are at work and how the seafloor changes over time are secrets that have long haunted scientists. Today, more is known about the surface topography of the planet Venus than is understood about many areas of the seafloor. The study of the planet’s evolution since its accretion 4.5 billion years ago comprises arguably the largest scale research project you can possibly undertake ... but many of the secrets of continental drift and plate tectonics are to be found underwater.

Dr Jo Whittaker
School of Geosciences, The University of Sydney

Talk given at ISS2011: Light & Matter, the 36th Professor Harry Messel International Science School, held at the University of Sydney in July 2011.