DOI 10.1016/j.jvolgeores.2020.107064 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.
| File | Pages | Size | Access | |
|---|---|---|---|---|
Publisher's official version | 32 | 5 Mo | ||
Supplementary material | - | 20 Ko | ||
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 Ko | ||
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 Mo | ||
Supplementary Fig. 3. Same as Supplementary Fig. 2 above the inactive Ono Caldera. | - | 1 Mo | ||
Supplementary Fig. 4. Same as Supplementary Fig. 2 above the western volcano of the Fatu Kapa area. | - | 1 Mo | ||
Supplementary Fig. 5. Same as Supplementary Fig. 2 above the eastern volcano of the Fatu Kapa area. | - | 2 Mo | ||
Supplementary Fig. 6. Same as Supplementary Fig. 2 above the Tasi Tulo area. | - | 990 Ko | ||
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 Ko |
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