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| West, Bp; Wilcock, Wsd; Sempere, Jc; Geli, Louis. |
| Both geophysical and geochemical evidence suggests the presence of along-axis asthenospheric flow toward the Australian-Antarctic Discordance (AAD) beneath the Southeast Indian Ridge (SEIR). We use a three-dimensional, finite-volume formulation of viscous flow to investigate the structure of asthenospheric motion beneath the SEIR. Our results show that simple continental separation in either a constant- or variable-viscosity mantle without horizontal temperature gradients is unable to reproduce the inferred asthenospheric flow velocities and observed geographic distribution of the ''Indian'' and ''Pacific'' upper mantle isotopic provinces. The presence of a cooler, more viscous mantle directly beneath the AAD is necessary to reproduce observed constraints.... |
| Tipo: Text |
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| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00068/17903/15439.pdf |
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| Cochran, Jr; Sempere, Jc; Seir Scientific Team,. |
| Although slow spreading ridges characterized by a deep axial valley and fast spreading ridges characterized by an axial bathymetric high have been extensively studied, the transition between these two modes of axial morphology is not well understood. We conducted a geophysical-survey of the intermediate spreading rate Southeast Indian Ridge between 88 degrees E and 118 degrees E, a 2300-km-long section of the ridge located between the Amsterdam hot spot and the Australian-Antarctic Discordance where satellite gravity data suggest that the Southeast Indian Ridge (SEIR) undergoes a change from an axial high in the west to an axial valley in the east. A basic change in axial morphology is found near 103 degrees 30'E in the shipboard data; the axis to the west... |
| Tipo: Text |
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| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00336/44688/45022.pdf |
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