EXPLORING THE OCEAN BASINS WITH SATELLITE ALTIMETER DATA

Plates are created at spreading ridges and destroyed (subducted) at the deep ocean trenches. All of the major ocean trenches are evident in the gravity map as linear troughs. The deep ocean basins away from the trenches are characterized by fracture zone gravity signatures inherited at the spreading ridge axis. This pattern is sometimes overprinted by linear volcanic chains which are believed to be formed as the plate moves over a stationary mantle plume. The hot plume head melts the mantle rocks which erupt on the surface as a hot spot. Because all of these major features are evident in the gravity maps, the geologic history of the ocean basins can now be established in great detail.