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Fluctuations du champ paléomagnétisme terrestre enregistrée par les laves de l'Archipel des Kerguelen (partie australe de l'Océan Indien) et détermination de leur direction de mise en place.

Abstract : Numerous observations of the magnetic field variations, uniformly distributed on the Earth's
surface for different time windows are needed to improve our knowledge on the inner-core dy-
namic. The first part of this work reports a paleomagnetic study, direction and intensity, carried
out on oligocene lava flows from the Kerguelen archipelago (49° 20'S, 70° 20'E) in order to im-
plement international databases. A between-flow angular standard deviation of 21.2 to 21.8°
from the geographic pole has been computed. This estimation of the oligocene paleosecular
variation agrees with McFadden et al. (1991) Model G for paleosecular variation between 22.5-
40 Ma. The 12 new paleointensity determinations reported are the first estimations obtained
for this archipelago with good technical quality. The mean VDM of 6.15+-2.1 10e22 increases
the mean oligocene estimate but is still lower than recent value ( 0.3 Ma), which seems abnormaly high.
Moreover, this work brings additional constraints to the geological researches carried out on
Kerguelen. We proposed a better location of the eruptive center for the different magnetic pro-
vinces and a detailed chronology of emplacement for a southeastern site by means of magnetic
fabric studies. Correlation of the polarity successions for fiv e sections with a global geomagne-
tic polarity scale allowed refinement of the emplacement time of these volcanic sequences and
consequently reevaluation of their extrusion rates.
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https://tel.archives-ouvertes.fr/tel-00002805
Contributor : Nathalie Pothier <>
Submitted on : Tuesday, May 6, 2003 - 11:30:12 AM
Last modification on : Tuesday, February 19, 2019 - 4:54:10 PM
Long-term archiving on: : Friday, April 2, 2010 - 6:34:05 PM

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  • HAL Id : tel-00002805, version 1

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Citation

Guillaume Plenier. Fluctuations du champ paléomagnétisme terrestre enregistrée par les laves de l'Archipel des Kerguelen (partie australe de l'Océan Indien) et détermination de leur direction de mise en place.. Géologie appliquée. Université Montpellier II - Sciences et Techniques du Languedoc, 2002. Français. ⟨tel-00002805⟩

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