What is the highest rift valley?
This is a tricky question, partly because the word “highest” can have several definitions in the context of ocean floor geology, and partly because of the complexity of seafloor spreading processes. If you define “highest” as the shallowest water depth at which a rift valley or spreading center exists, the winner would be the Mid Atlantic Ridge (MAR). Some of the underwater mountains created along this rift valley lie at only ~500 meters water depth. If you define “highest” as the greatest distance between the shallowest point on the ridge and the deepest point (the elevation of the ridge), the winner would again be the MAR. There are places — usually at the intersection of the ridge and a transform fault — on the MAR where there is a 6000 meter elevation change. However, if instead you define “highest” as the average ridge height compared to the average seafloor depth, the winner would be the Southern Eastern Pacific Ridge (SEPR) in the South Pacific Ocean. This is because the SEPR
