A systematic analysis of the Mid-Atlantic Ridge morphology and gravity between 15 deg N and 40 deg N - Constraints of the thermal structure

Multibeam bathymetry data obtained along a 2400-km long section of the Mid-Atlantic Kidge (MAK) from 15 deg N to the Azores platform (40 deg N) and satellite-derived gravity data were used to calculate the mantle Bouguer anomaly (MBA) along this portion of the MAR. Both data sets were used to determ...

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Bibliographic Details
Published in:Journal of Geophysical Research 1998-10, Vol.103 (B10), p.24
Main Authors: Thibaud, Remy, Gente, Pascal, Maia, Marcia
Format: Article
Language:English
Online Access:Get full text
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Summary:Multibeam bathymetry data obtained along a 2400-km long section of the Mid-Atlantic Kidge (MAK) from 15 deg N to the Azores platform (40 deg N) and satellite-derived gravity data were used to calculate the mantle Bouguer anomaly (MBA) along this portion of the MAR. Both data sets were used to determine the relations between gravity anomalies and topographic variations and discuss these in terms of thermal difference. A long-wavelength influence of the Azores hot spot is characterized by a gentle, continuous slope of the average ridge axial depth and a general gradient in the along-axis MBA profile. This thermal influence of the Azores hot spot controls a systematic southward propagation of the spreading segments at least to 26 deg 30 min N. South of 26 deg 30 min N, the direction of the segment propagation is controlled by the local difference in the thermal state between adjacent segments. Except on the Azores platform, the systematic along-axis 11-90-km-long wavelength segmentation is independent of the long-wavelength influence of the Azores. We propose that these different segment types correspond to a temporal evolution of the rift valley morphology over periods of several million years. (Author)
ISSN:0148-0227