The intermediate-wavelength magnetic anomaly maps of the North Atlantic Ocean derived from satellite and shipborne data

SUMMARY Two intermediate-wavelength magnetic anomaly maps of the North Atlantic Ocean are derived based on satellite and marine magnetic observations. The satellite map is produced from the covariant features of POGO and Magsat dawn and Magsat dusk magnetic anomalies. The marine map is compiled using shipborne data collected since 1965. The two maps are in excellent agreement over well-defined anomalies both in location and amplitude, suggesting that these anomalies are real and reflect magnetization contrasts in the oceanic lithosphere. Both maps show the intermediate-wavelength seafloor-spreading anomalies of the Cretaceous quiet zone of the central North Atlantic Ocean as well as the negative seafloor-spreading anomaly of the Labrador Sea caused by dominantly reversed polarity periods. The Iceland hotspot, Alpha Ridge, Azores High, King's Trough and the Rockall microcontinent have positive anomalies. There is no consistent magnetic signature associated with the ocean-continent boundary, although the deep sedimentary basin of Nova Scotia is delineated by a well-defined negative anomaly.