A geophysical study of the Atlantis-Meteor seamount complex

Abstract

The depth of the ocean floor in general increases systematically with increasing crustal age (e.g. Sclater and Francheteau, 1970; Parsons and Sclater, 1977). This increase of depth further away from a mid-ocean ridge crest can be explained by thermal models for the evolution of the oceanic lithosphere. There are, however, large portions of oceanfloor whose depth deviate from the predicted depth-age relation (depth anomalies, Menard, 1973). Cochran and Talwani (1977) examined depth anomalies throughout the world's oceans and noticed a relation between "the intermediate wavelength positive features (both gravity and depth) and areas of extensive off-ridge volcanism (c.f. Menard, 1973; Anderson et aI, 1973; Sclater et aI, 1975). The volcanism which is not associated with plate margin processes is called intra-plate volcanism (Turcotte and Oxburgh, 1978). The Atlantis-Meteor seamount group forms a large volcanic complex in the central North Atlantic ocean, situated some 700 km south of the Azores. The whole area around this complex is too shallow in terms of the depth-age curve and constitutes a positive depth anomaly. It actually forms the most southern part of the North Atlantic Gravity High (Cochran and Talwani, 1978), which extends from Iceland to about 300 N and which comprises areas of different plate tectonic setting. The study of Cochran and Talwani (1978) was based upon 1°*1° averages. In the area around the Atlantis-Meteor complex there was not enough gravity data to calculate 1°*1° averages (see Cochran and Talwani, 1978)