CRUSTAL AGE BETWEEN THE CLIPPERTON AND CLARION FRACTURE-ZONES

Magnetic anomalies of 52-80 Ma age have been mapped in the equatorial Pacific in a region where they were previously unrecognized. These anomalies, now at 7-degrees-N are best modeled with crustal rocks of negative inclination, apparently because the crust was formed at a spreading ridge that was south of the magnetic equator in Late Cretaceous-Early Tertiary time. Magnetic anomalies recorded along a 5900-km trackline that follows a flowline of crustal generation show one long period, from 12 to 31 Ma, of apparent constant half-spreading rate over the 0 to 80 Ma represented.