Reversal transition widths and fast-spreading centers

It is generally assumed by geomagnetists that spreading centers with the fastest separation rates should ultimately yield the most information concerning short-period behavior of the paleomagnetic field. We present results here that may indicate otherwise. Marine anomalies over the Reykjanes Ridge, Juan de Fuca Ridge, Gorda Rise, and East Pacific Rise are analyzed to determine apparent transition width of the Brunhes-Matuyama reversal boundary and Jaramillo event. Spreading rates vary by a factor of 10 between these areas and we find a nearly linear increase in transition width with increase in spreading rate, except for the slow-spreading Reykjanes Ridge. We interpret this trend with an earlier-proposed, depth-dependent time of magnetization for newly created ocean crust.