Deep structure of the southern Kerguelen Plateau (southern Indian Ocean) from ocean bottom seismometer wide-angle seismic data

Wide-angle seismic data collected during the Kerguelen ocean bottom seismometer experiment provide the first images of the deep structure of the southern Kerguelen Plateau and support a new interpretation of the origin of the plateau. Velocity models based on travel time inversions and reflectivity...

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Main Authors: Operto, D., /Charvis, Philippe
Format: Text
Language:English
Published: 1996
Subjects:
Online Access:https://www.documentation.ird.fr/hor/fdi:010083753
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spelling ftird:oai:ird.fr:fdi:010083753 2024-09-15T17:46:58+00:00 Deep structure of the southern Kerguelen Plateau (southern Indian Ocean) from ocean bottom seismometer wide-angle seismic data Operto, D. /Charvis, Philippe KERGUELEN OCEAN INDIEN 1996 https://www.documentation.ird.fr/hor/fdi:010083753 EN eng https://www.documentation.ird.fr/hor/fdi:010083753 oai:ird.fr:fdi:010083753 Operto D., Charvis Philippe. Deep structure of the southern Kerguelen Plateau (southern Indian Ocean) from ocean bottom seismometer wide-angle seismic data. 1996, 101 (B11), 25077-25103 text 1996 ftird 2024-08-15T05:57:43Z Wide-angle seismic data collected during the Kerguelen ocean bottom seismometer experiment provide the first images of the deep structure of the southern Kerguelen Plateau and support a new interpretation of the origin of the plateau. Velocity models based on travel time inversions and reflectivity synthetic seismograms show a 22-km-thick crust composed of average 1.6 km of sedimentary cover, average 5.3 km of upper crust, average 11.0 km of lower crust, and a 4- to 6-km-thick reflective zone immediately above Moho. Velocities in the upper crust (from 3.8-4.5 km/s at top to 6.0-6.5 km/s at bottom) are consistent with the basaltic nature of this layer, the top of which was sampled during the Ocean Drilling Program. Velocities in the lower crust increase continuously from 6.60 km/s at the top to 6.90 km/s at 19.5 km depth. The reflective zone at the base of the crust identified by wide-angle reflections is observed only along the NNW-SSE direction. It consists of alternating high- and low-velocity layers with an average velocity of 6.70 km/s in the NNW-SSE direction and ?6.90 km/s in the perpendicular direction. Strong azimuthal anisotropy is also observed in the upper mantle with velocities of 8.60 and 8.00 km/s, in the NNW-SSE and E-W directions, respectively. The absence of high velocities at the base of the crust that characterizes many large-volume mafic provinces, the reflective lower crust, and anisotropy in upper mantle suggest that the southern Kerguelen Plateau represents a stretched continental fragment overlain by basaltic flows isolated from the Antarctic margin during the early opening of the Indian Ocean Text Antarc* Antarctic 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
description Wide-angle seismic data collected during the Kerguelen ocean bottom seismometer experiment provide the first images of the deep structure of the southern Kerguelen Plateau and support a new interpretation of the origin of the plateau. Velocity models based on travel time inversions and reflectivity synthetic seismograms show a 22-km-thick crust composed of average 1.6 km of sedimentary cover, average 5.3 km of upper crust, average 11.0 km of lower crust, and a 4- to 6-km-thick reflective zone immediately above Moho. Velocities in the upper crust (from 3.8-4.5 km/s at top to 6.0-6.5 km/s at bottom) are consistent with the basaltic nature of this layer, the top of which was sampled during the Ocean Drilling Program. Velocities in the lower crust increase continuously from 6.60 km/s at the top to 6.90 km/s at 19.5 km depth. The reflective zone at the base of the crust identified by wide-angle reflections is observed only along the NNW-SSE direction. It consists of alternating high- and low-velocity layers with an average velocity of 6.70 km/s in the NNW-SSE direction and ?6.90 km/s in the perpendicular direction. Strong azimuthal anisotropy is also observed in the upper mantle with velocities of 8.60 and 8.00 km/s, in the NNW-SSE and E-W directions, respectively. The absence of high velocities at the base of the crust that characterizes many large-volume mafic provinces, the reflective lower crust, and anisotropy in upper mantle suggest that the southern Kerguelen Plateau represents a stretched continental fragment overlain by basaltic flows isolated from the Antarctic margin during the early opening of the Indian Ocean
format Text
author Operto, D.
/Charvis, Philippe
spellingShingle Operto, D.
/Charvis, Philippe
Deep structure of the southern Kerguelen Plateau (southern Indian Ocean) from ocean bottom seismometer wide-angle seismic data
author_facet Operto, D.
/Charvis, Philippe
author_sort Operto, D.
title Deep structure of the southern Kerguelen Plateau (southern Indian Ocean) from ocean bottom seismometer wide-angle seismic data
title_short Deep structure of the southern Kerguelen Plateau (southern Indian Ocean) from ocean bottom seismometer wide-angle seismic data
title_full Deep structure of the southern Kerguelen Plateau (southern Indian Ocean) from ocean bottom seismometer wide-angle seismic data
title_fullStr Deep structure of the southern Kerguelen Plateau (southern Indian Ocean) from ocean bottom seismometer wide-angle seismic data
title_full_unstemmed Deep structure of the southern Kerguelen Plateau (southern Indian Ocean) from ocean bottom seismometer wide-angle seismic data
title_sort deep structure of the southern kerguelen plateau (southern indian ocean) from ocean bottom seismometer wide-angle seismic data
publishDate 1996
url https://www.documentation.ird.fr/hor/fdi:010083753
op_coverage KERGUELEN
OCEAN INDIEN
genre Antarc*
Antarctic
genre_facet Antarc*
Antarctic
op_relation https://www.documentation.ird.fr/hor/fdi:010083753
oai:ird.fr:fdi:010083753
Operto D., Charvis Philippe. Deep structure of the southern Kerguelen Plateau (southern Indian Ocean) from ocean bottom seismometer wide-angle seismic data. 1996, 101 (B11), 25077-25103
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