|Anomalies isostatiques sous le bassin de Crozet et la dorsale est-indienne|
Recq, M. (1983). Anomalies isostatiques sous le bassin de Crozet et la dorsale est-indienne. Bull. Soc. Géol. Fr. 25(6): 963-972
In: Bulletin de la Société Géologique de France. Société Géologique de France: Paris. ISSN 0037-9409, more
Conditions of isostatic balance of structures of the southern Indian Ocean, mainly the Crozet Basin and the south-East Indian Ridge, were investigated from available deep seismic soundings. In the southwestern Indian Ocean, aseismic ridges are in loacl isostatic equilibrium with respect to the nearby deep oceanic basins. This result cannot be extended to the whole southern Indian Ocean. The weigth A of columns with constant section and height relative to a 40 km deep reference level, with the assumption of a homogeneous mantle, gets its highest value underneath the East Indian Ridge. We demonstrate that there are relationships similar to that of Parsons and Sclater between A and: 1) the longitude, 2) the range from the spreading centre, 3) the age of structures, 4) the water depth. The Crozet Basin and the East-Indian Ridge are isostatically compensated by a low-density mantle down to 50 km deep. The compensation level is 80 km deep. The influence of the Altantic-Indian Ridge on isostatic balance appears to be weak. A values for submarine plateaus are nearly constant, whatever their locations.