An interpretation of complex geophysical measurements in the region of the Dacia Seamount

Results of a geomagnetic, gravimetric and echo-sounding survey of gravity and magnetic anomalies in the Atlantic Ocean in the area of the Dacia Seamount are interpreted. The data allowed the construction of a bottom relief map, maps of gravitational anomalies in the Faye and Bouguer reductions, and maps of the anomalous Z and H magnetic fields. The Z magnetic anomaly is shown to be isometric and to correspond to the magnetic field of a sphere with vertical magnetization. The surface of the anomalous body is observed to correspond to the relief along the 1000-m isobath, with a magnetic susceptibility characteristic of andesite lava. From the gravimetric data it is concluded that the Faye anomaly is determined by topographic relief, while the Bouguer anomaly is not distinct from the background Atlantic gravitational field. Results are consistent with the breakdown of isostatic compensation near an underwater volcanic island.