Radiometric dating of three large volume flank collapses in the Lesser Antilles Arc | INSTITUT DE PHYSIQUE DU GLOBE DE PARIS

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  Radiometric dating of three large volume flank collapses in the Lesser Antilles Arc

Publication Type:

Journal Article

Source:

Journal of Volcanology and Geothermal Research, Volume 176, Issue 4, p.485-492 (2008)

ISBN:

0377-0273

Accession Number:

WOS:000260728900005

Keywords:

UMR 7154, Volcanologie ; N° Contribution : 2363

Abstract:

It is now recognised that flank collapses are a recurrent process in the evolution of the Lesser Antilles Arc volcanoes. Large magnitude debris-avalanche deposits have been identified off the coast of Dominica, Martinique and St. Lucia, with associated volumes up to 20 km(3) [Deplus, C., Le Friant, A., Boudon, G., Komorowski. J.-C., Villemant, B., Harford, C., Segoufin, J., Cheminee. J.-L, 2001. Submarine evidence for large-scale debris avalanches in the Lesser Antilles Arc. Earth Planet. Sci. Lett., 192: 145-157.]. We present new radiometric dating of three major events using the K-Ar Cassignol-Gillot technique. In the Qualibou depression of St. Lucia, a collapse has been constrained by dome emplacement prior to 95 +/- 2 ka. In Dominica, where repetitive flank collapse events have occurred [Le Friant, A., Boudon, G., Komorowski, J.-C., Deplus, C., 2002. Lile de la Dominique, l'origine des avalanches de debris les plus volumineuses de l'arc des Petites Antilles. C.R. Geoscience, 334: 235-243], the Plat Pays event probably occurred after 96 2 ka. Inside the depression caused by this event, Scotts Head, which is interpreted as a proximal megabloc from the subsequent Soufriere avalanche event has been dated at 14 I ka, providing an older bound for this event. On Martinique three different domes within the Carbets structure dated at 337 5 ka constrain the age of this high magnitude event. Finally, these results obtained from three of the most voluminous flank collapses provide constraints to estimate the recurrence of these events, which represent one of the major hazards associated with volcanoes of the Lesser Antilles Arc. (C) 2008 Elsevier B.V. All rights reserved.