Small-scale crustal variability within an intraplate structure : the Crozet Bank (southern Indian Ocean)
The Crozet Bank, the easternmost region of the Crozet Plateau (austral Indian Ocean), is capped by two gropus of islands which form the Crozet Archipelago (Terres Australes and Antarctiques Françaises). A N-S-trending 2 km deep basin, the Indivat Basin, extends between the two groups of islands and...
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ftird:oai:ird.fr:fdi:010019275 2024-09-15T17:43:12+00:00 Small-scale crustal variability within an intraplate structure : the Crozet Bank (southern Indian Ocean) Recq, M. Goslin, J. /Charvis, Philippe Operto, S. OCEAN INDIEN ILES CROZET 1998 https://www.documentation.ird.fr/hor/fdi:010019275 EN eng https://www.documentation.ird.fr/hor/fdi:010019275 oai:ird.fr:fdi:010019275 Recq M., Goslin J., Charvis Philippe, Operto S. Small-scale crustal variability within an intraplate structure : the Crozet Bank (southern Indian Ocean). Geophysical Journal International, 1998, 134, p. 145-156 CROUTE OCEANIQUE STRUCTURE POINT CHAUD PROFIL SISMIQUE SISMOGRAMME BATHYMETRIE GRAVIMETRIE MODELISATION text 1998 ftird 2024-08-15T05:57:43Z The Crozet Bank, the easternmost region of the Crozet Plateau (austral Indian Ocean), is capped by two gropus of islands which form the Crozet Archipelago (Terres Australes and Antarctiques Françaises). A N-S-trending 2 km deep basin, the Indivat Basin, extends between the two groups of islands and bisects the Crozet Bank into two separate domains. The interpretation of the KeOBS8 seismic refraction profile shot during the KeOBS/MD66 cruise (January-February 1991) over the eastern Crozet Plateau was carried out by ray tracing and the computation of synthetic seismograms. This interpretation leads to a rather complex seismic structure and outlines a pronounced eastward crustal thinning from 16.5 to 10 km at the expense of layer 2. The thinning of the crust is abrupt east of the Indivat Basin. Unlike below the Hawaiian Islands and the Marquesas Islands, no underplated mantle material underlies the crust of the Crozet Bank. Moreover, this deep seismic sounding has further revealed tha high-velocity outcropping the seabed 30 km east of Ile aux Cochons could be a major structural feature, deeply rooted withn he lower crust. The occurrence of this feature (a submarine volcano ?) is associated with a mantle dyke causing a steep shallowing of the lower crustal interfaces. Gravity modelling was performed along line KeOBS8, with a density structure deduced from the seismic section, to model free-air anomalies derived from altimetry data. This modelling confirms that the Indivat Basin, underlined by a gravity low running roughly N-S between the two groups of islands, is a major structural boundary. As the model generates medium-wavelength anomalies of adequate amplitude, it also confirms that the volcano, located west of the Indivat Basin, is a deeply rooted feature. The Crozet Bank clearly appears as a plume-affected structure, which may have originated from a deep thermal anomaly within the lithsophere. (D'après résumé d'auteur) Text Antarc* Antarctique* IRD (Institute de recherche pour le développement): Horizon |
institution |
Open Polar |
collection |
IRD (Institute de recherche pour le développement): Horizon |
op_collection_id |
ftird |
language |
English |
topic |
CROUTE OCEANIQUE STRUCTURE POINT CHAUD PROFIL SISMIQUE SISMOGRAMME BATHYMETRIE GRAVIMETRIE MODELISATION |
spellingShingle |
CROUTE OCEANIQUE STRUCTURE POINT CHAUD PROFIL SISMIQUE SISMOGRAMME BATHYMETRIE GRAVIMETRIE MODELISATION Recq, M. Goslin, J. /Charvis, Philippe Operto, S. Small-scale crustal variability within an intraplate structure : the Crozet Bank (southern Indian Ocean) |
topic_facet |
CROUTE OCEANIQUE STRUCTURE POINT CHAUD PROFIL SISMIQUE SISMOGRAMME BATHYMETRIE GRAVIMETRIE MODELISATION |
description |
The Crozet Bank, the easternmost region of the Crozet Plateau (austral Indian Ocean), is capped by two gropus of islands which form the Crozet Archipelago (Terres Australes and Antarctiques Françaises). A N-S-trending 2 km deep basin, the Indivat Basin, extends between the two groups of islands and bisects the Crozet Bank into two separate domains. The interpretation of the KeOBS8 seismic refraction profile shot during the KeOBS/MD66 cruise (January-February 1991) over the eastern Crozet Plateau was carried out by ray tracing and the computation of synthetic seismograms. This interpretation leads to a rather complex seismic structure and outlines a pronounced eastward crustal thinning from 16.5 to 10 km at the expense of layer 2. The thinning of the crust is abrupt east of the Indivat Basin. Unlike below the Hawaiian Islands and the Marquesas Islands, no underplated mantle material underlies the crust of the Crozet Bank. Moreover, this deep seismic sounding has further revealed tha high-velocity outcropping the seabed 30 km east of Ile aux Cochons could be a major structural feature, deeply rooted withn he lower crust. The occurrence of this feature (a submarine volcano ?) is associated with a mantle dyke causing a steep shallowing of the lower crustal interfaces. Gravity modelling was performed along line KeOBS8, with a density structure deduced from the seismic section, to model free-air anomalies derived from altimetry data. This modelling confirms that the Indivat Basin, underlined by a gravity low running roughly N-S between the two groups of islands, is a major structural boundary. As the model generates medium-wavelength anomalies of adequate amplitude, it also confirms that the volcano, located west of the Indivat Basin, is a deeply rooted feature. The Crozet Bank clearly appears as a plume-affected structure, which may have originated from a deep thermal anomaly within the lithsophere. (D'après résumé d'auteur) |
format |
Text |
author |
Recq, M. Goslin, J. /Charvis, Philippe Operto, S. |
author_facet |
Recq, M. Goslin, J. /Charvis, Philippe Operto, S. |
author_sort |
Recq, M. |
title |
Small-scale crustal variability within an intraplate structure : the Crozet Bank (southern Indian Ocean) |
title_short |
Small-scale crustal variability within an intraplate structure : the Crozet Bank (southern Indian Ocean) |
title_full |
Small-scale crustal variability within an intraplate structure : the Crozet Bank (southern Indian Ocean) |
title_fullStr |
Small-scale crustal variability within an intraplate structure : the Crozet Bank (southern Indian Ocean) |
title_full_unstemmed |
Small-scale crustal variability within an intraplate structure : the Crozet Bank (southern Indian Ocean) |
title_sort |
small-scale crustal variability within an intraplate structure : the crozet bank (southern indian ocean) |
publishDate |
1998 |
url |
https://www.documentation.ird.fr/hor/fdi:010019275 |
op_coverage |
OCEAN INDIEN ILES CROZET |
genre |
Antarc* Antarctique* |
genre_facet |
Antarc* Antarctique* |
op_relation |
https://www.documentation.ird.fr/hor/fdi:010019275 oai:ird.fr:fdi:010019275 Recq M., Goslin J., Charvis Philippe, Operto S. Small-scale crustal variability within an intraplate structure : the Crozet Bank (southern Indian Ocean). Geophysical Journal International, 1998, 134, p. 145-156 |
_version_ |
1810490065591205888 |