Widespread volcanism Southeast of Futuna Island (SW Pacific Ocean): Near-seafloor magnetic dating and regional consequences

Type Article
Date 2020-11
Language English
Author(s) Szitkar Florent1, Dyment Jérôme2, Fouquet Yves3
Affiliation(s) 1 : NGU, The Geological Survey of Norway, Trondheim, Norway
2 : Institut de Physique du Globe de Paris, CNRS, Paris, France
3 : Ifremer, GM, F-29280 Plouzané, France
Source Journal Of Volcanology And Geothermal Research (0377-0273) (Elsevier BV), 2020-11 , Vol. 406 , P. 107064 (9p.)
DOI 10.1016/j.jvolgeores.2020.107064
Abstract

Near-seafloor bathymetric and magnetic data have been collected by Autonomous Underwater Vehicle (AUV) and manned submersible (DSS) over a volcanically active area southeast of Futuna Island, French Territory of Wallis-and-Futuna, in the Southwestern Pacific Ocean. Located at the edge of the Lau and North Fiji basins, at the convergence of the Pacific and Australian plates, this area is characterized by intense volcanic and tectonic activity. Direct observation by submersible reveals that the seafloor is covered by recent lava flows, volcanoes and large, active or inactive calderas filled by smooth lava flows and eventually hosting hydrothermal sites. We investigate the volcanic chronology by combining a Bayesian inversion of the AUV-gridded magnetic data with an inversion of the submersible data specifically designed to estimate the rock magnetic polarity and absolute magnetization. We show that some volcanoes predate the last (Brunhes-Matuyama) magnetic polarity reversal 780 kyr ago whereas their neighbors exhibit a normal polarity and appear to be recent. This result suggests that the seafloor in this region has undergone continuous and sparse volcanic activity over the last few million years.

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Publisher's official version 32 5 MB Open access
Supplementary material 20 KB Open access
Supplementary Fig. 1. DSS Nautile data over the Kulo Lasi Caldera. (Left) Absolute magnetizations along the routes of the Nautile. (Right), Magnetization polarities along the routes of the Nautile. .. 686 KB Open access
Supplementary Fig. 2. (Top Left) Magnetic anomaly over the Kulo Lasi Caldera derived from the AUV data. (Bottom Left) High-resolution bathymetry of the Kulo Lasi Caldera. (Center row) Equivalent ... 1 MB Open access
Supplementary Fig. 3. Same as Supplementary Fig. 2 above the inactive Ono Caldera. 1 MB Open access
Supplementary Fig. 4. Same as Supplementary Fig. 2 above the western volcano of the Fatu Kapa area. 1 MB Open access
Supplementary Fig. 5. Same as Supplementary Fig. 2 above the eastern volcano of the Fatu Kapa area. 2 MB Open access
Supplementary Fig. 6. Same as Supplementary Fig. 2 above the Tasi Tulo area. 990 KB Open access
Supplementary Fig. 7. Delineation of the Tasi Tulo volcanoes based on their bathymetric expression. (Top Left) High-resolution bathymetry of the Tasi Tulo area. (Bottom Left) Equivalent magnetization 1023 KB Open access
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