Oceanic Ridges and Eustatic Changes in Sea Level

Abstract

Although the old idea of orogeny causing changes in sea level has recently been revived, this effect is too small to cause major transgressions or regressions^1,2. Oceanic ridges, however, are considerably larger than continental mountain ranges and could cause important changes in sea level^3,4. The mechanism of the formation of these ridges has been disputed^5,6, but their genesis is immaterial to this hypothesis. The hypothesis requires the ridge to be a site of high heat flow which is in local isostatic equilibrium. The heat input causes the material of the ridge to decrease in density and to increase in volume. When the sources of heat are lost the reverse occurs.