BLAKE RIDGE AEROMAGNETIC SURVEY
NAVAL OCEANOGRAPHIC OFFICE NSTL STATION MS
Pagination or Media Count:
Two positive magnetic lineations are revealed in an aeromagnetic survey of a 20,000 square mile area over the Blake Ridge. The two magnetic anomalies are generally parallel to the continental slope, but show no particular relation to the Blake Ridge which they cross at an angle of approximately 70 degrees. The larger of the two anomalies occurs near the edge of the continental shelf in the northwest corner of the survey area. It is believed to be caused by a large body of highly magnetic material injected or extruded along a fracture or crustal adjustment on the seaward edge of a sedimentary trough. The smaller anomaly crosses through the center of the survey area. Computations indicate that it is caused by a susceptibility contrast of 0. 010 cgs between a large intrusion of mantle material and the surrounding crustal layers.