The sedimentation pattern around the Atlantis-Meteor seamount complex: a model study

Abstract

The Atlantis-Meteor seamount group forms a large volcanic complex situated about 700 km to the south of the Azores. Not counting the turbidite sedimentation of the Madeira abyssal plain to the east, the area around the complex is characterized by a relatively thick sedimentary layer containing a strong and often shielding reflector. The thickness of the sediments above the strong reflector, as well as the total sediment thickness, shows an asymmetry with respect to the seamount complex: west of the seamounts a thick sedimentary cover can be found, while virtually no sediments occur to the east of the seamounts. The depth anomaly in the area around the seamount complex is positive. The depth anomaly contours correlate well with the regional isopachs of the sediment above the strong reflector. This correlation led to the construction of a simple carbonate sedimentation model. In this model paleodepth reconstructions were used to calculate the carbonate sedimentation. The model explains the most important aspects of the sedimentation pattern. Besides it led to the conclusion that the age of the strongly reflecting layer cannot be much older than Miocene. This conclusion is sustained by the absence of sediments in the southwestern part of the area. Therefore it is unlikely that the volcanism in this area and the anomalous depth originated on the spreading centre. The model is not sensitive enough to detect variations in age between the different seamounts. Since there are no DSDP sites in this area the age determination based on the sedimentation pattern forms a useful alternative for the time being.