FN Archimer Export Format PT J TI Extensive hydrothermal activity revealed by multi-tracer survey in the Wallis and Futuna region (SW Pacific) BT AF KONN, Cecile FOURRE, E. JEAN-BAPTISTE, P. DONVAL, Jean-Pierre GUYADER, Vivien BIROT, Dominique ALIX, Anne-Sophie GAILLOT, Arnaud PEREZ, Florian DAPOIGNY, A. PELLETER, Ewan RESING, J. A. CHARLOU, Jean-Luc FOUQUET, Yves AS 1:1;2:3;3:3;4:1;5:1;6:1;7:1;8:2;9:3;10:3;11:1;12:4,5;13:1;14:1; FF 1:PDG-REM-GM-LCG;2:;3:;4:PDG-REM-GM-LCG;5:PDG-REM-GM-LCG;6:PDG-REM-GM-LCG;7:PDG-REM-GM-LCG;8:PDG-REM-GM-CTDI;9:PDG-REM-GM-LGM;10:;11:PDG-REM-GM-LCG;12:;13:PDG-REM-GM-LCG;14:PDG-REM-GM-LCG; C1 IFREMER, Lab Cycles Geochim & Ressources, CS10070, F-29280 Plouzane, France. IFREMER, Serv Cartog Traitement Donnees & Instrument, CS10070, F-29280 Plouzane, France. UMR 8212CEA CNRS UVSQ, LSCE, F-91191 Gif Sur Yvette, France. Univ Washington, Joint Inst Study Atmosphere & Ocean, 7600S & Point Way NE, Seattle, WA 98115 USA. NOAA PMEL, 7600S & Point Way NE, Seattle, WA 98115 USA. C2 IFREMER, FRANCE IFREMER, FRANCE LSCE, FRANCE UNIV WASHINGTON, USA NOAA, USA SI BREST SE PDG-REM-GM-LCG PDG-REM-GM-CTDI PDG-REM-GM-LGM IN WOS Ifremer jusqu'en 2018 copubli-france copubli-int-hors-europe IF 2.48 TC 10 UR https://archimer.ifremer.fr/doc/00347/45848/45505.pdf LA English DT Article CR FUTUNA FUTUNA 2 LEG1 FUTUNA 2 LEG2 FUTUNA 3 BO L'Atalante AB The study area is close to the Wallis and Futuna Islands in the French EEZ. It exists on the western boundary of the fastest tectonic area in the world at the junction of the Lau and North-Fiji basins. At this place, the unstable back-arc accommodates the plate motion in three ways: (i) the north Fiji transform fault, (ii) numerous unstable spreading ridges, and (iii) large areas of recent volcanic activity. This instability creates bountiful opportunity for hydrothermal discharge to occur. Based on geochemical (CH4, TDM, 3He) and geophysical (nephelometry) tracer surveys: (1) no hydrothermal activity could be found on the Futuna Spreading Center (FSC) which sets the western limit of hydrothermal activity; (2) four distinct hydrothermal active areas were identified: Kulo Lasi Caldera, Amanaki Volcano, Fatu Kapa and Tasi Tulo areas; (3) extensive and diverse hydrothermal manifestations were observed and especially a 2D distribution of the sources. At Kulo Lasi, our data and especially tracer ratios (CH4/3He ~ 50×106 and CH4/TDM ~ 4.5) reveal a transient CH4 input, with elevated levels of CH4 measured in 2010, that had vanished in 2011 (Futuna 2), most likely caused by an eruptive magmatic event. By contrast at Amanaki, vertical tracer profiles and tracer ratios point to typical seawater / basalt interactions. Fatu Kapa is characterized by a substantial spatial variability of the hydrothermal water column anomalies, most likely due to widespread focused and diffuse hydrothermal discharge in the area. In the Tasi Tulo zone, the hydrothermal signal is characterized by a total lack of turbidity, although other tracer anomalies are in the same range as in nearby Fatu Kapa. The background data set revealed the presence of a Mn and 3He chronic plume due to the extensive and cumulative venting over the entire area. To that respect, we believe that the joined domain composed of our active area and the nearby active area discovered in the East by Lupton et al. (2012) highly contribute to the extensive Tonga-Fiji plume and which thus may not originate from a sole source near the Samoa. Our results also emphasize and support the idea that back-arc hydrothermal systems have a significant input to the regional and global ocean and maybe more important than their MOR analogues. PY 2016 PD OCT SO Deep-sea Research Part I-oceanographic Research Papers SN 0967-0637 PU Pergamon-elsevier Science Ltd VL 116 UT 000385326700013 BP 127 EP 144 DI 10.1016/j.dsr.2016.07.012 ID 45848 ER EF