A Topographic Interpretation of the Mathematician Ridge, Clipperton Ridge, East Pacific Rise System

WITHIN the framework of plate tectonics, dating of the ocean floor has been almost exclusively achieved by studies of magnetic anomalies. But a north–south striking mid-ocean ridge system generating new seafloor in the equatorial region produces magnetic anomalies which are of small amplitude and are frequently distorted and disguised by magnetic “noise”. The correspondence between the absolute depth of oceanic crust and its age1 has provided an alternative method of age dating the oceanic crust anywhere in the world's oceans, provided, of course, that the crust was generated by a seafloor spreading system. Such a correlation tool has been used on the East Pacific Rise (Fig. 1) between 20° N and the equator1 and between 0° and 20° S (ref. 2).