THE SEA-FLOOR SPREADING RATE DEPENDENCE OF THE ANOMALOUS SKEWNESS OF MARINE MAGNETIC-ANOMALIES

We have determined the anomalous skewness of marine magnetic anomalies other than anomaly 33-34 in slow spreading regimes in the Arctic, Atlantic and Indian Oceans, and found a significant dependence of the anomalous skewness on the spreading rate. The anomalous skewness is highest for slow spreading, and insignificant for spreading above 6 cm yr-1. Also, the anomalous skewness of anomaly 33-34 is significantly larger than that of anomalies 25-26 and 20-21. Whether or not anomalies M2-M4 exhibit anomalous skewness is uncertain because of the large variability in their shapes. To facilitate the study of anomalous skewness of marine magnetic anomalies, we have developed an analytic method, based on functions calculated directly from the magnetic profiles that does not require a priori knowledge about the exact locations of magnetization contrasts.