Satellite magnetic anomalies related to seafloor spreading in the South Atlantic Ocean

Oceanic magnetic anomalies have been observed from satellite. The strongest anomalies are the long-wavelength components of the sea-floor spreading signature. Unfortunately, because of technical issues involving the treatment of satellite magnetic data, these signals are obscured in the South Atlantic Ocean because they trend north-south However, a map does exist in which such features are observed, essentially because of a better data processing technique. Further, this map agrees with a physically motivated model based on non-satellite magnetic input. Hence, with properly treated data, the magnetic anomaly maps should be useful for saying something about the geology, rather than vice-versa. This situation will be considerably improved by ongoing advances in methods and new data sets. The amplitude of the observations, a factor of two larger than previous estimates, confirms that the extrusive basaltic layer alone is inadequate to produce the signal and that deeper oceanic sources are required.