GLOBAL SEA-FLOOR TOPOGRAPHY FROM SATELLITE ALTIMETRY AND SHIP DEPTH SOUNDINGS

A digital bathymetric map of the oceans with a horizontal resolution o f 1 to 12 kilometers was derived by combining available depth sounding s with high-resolution marine gravity information from the Geosat and ERS-1 spacecraft. Previous global bathymetric maps lacked features suc h as the 1600-kilometer-long Foundation Seamounts chain in the South P acific. This map shows relations among the distributions of depth, sea floor area, and sea floor age that do not fit the predictions of dete rministic models of subsidence due to lithosphere cooling but may be e xplained by a stochastic model in which randomly distributed reheating events warm the lithosphere and raise the ocean floor.