1. Heterogeneity of volatile sources along the Halmahera arc, Indonesia
- Author
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Alessandro Aiuppa, François Nauret, Clive Oppenheimer, Nia Haerani, V. I. Tsanev, Hilma Alfianti, B.U. Saing, Philipson Bani, M. Marlia, Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement et la société-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), Department of Geography, University of Cambridge, University of Cambridge [UK] (CAM), Dipartimento di Scienze della Terra e del Mare [Palermo] (DiSTeM), Università degli studi di Palermo - University of Palermo, Center for Volcanology and Geological Hazard Mitigation (CVGHM), Badan Geologi, ANR-10-LABX-0006,CLERVOLC,Clermont-Ferrand centre for research on volcanism(2010), ANR-16-IDEX-0001,CAP 20-25,CAP 20-25(2016), Bani P., Nauret F., Oppenheimer C., Aiuppa A., Saing B.U., Haerani N., Alfianti H., Marlia M., and Tsanev V.
- Subjects
geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Mantle wedge ,Subduction ,Lava ,Arc-scale degassing budget, Halmahera volcanoes, Sediment contribution and fluid flux, Variability of arc magma ,Geochemistry ,Partial melting ,Variability of arc magma ,Crust ,Halmahera volcanoes ,Geodynamics ,010502 geochemistry & geophysics ,01 natural sciences ,Mantle (geology) ,Sediment contribution and fluid flux ,Geophysics ,Volcano ,13. Climate action ,Geochemistry and Petrology ,[SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry ,[SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology ,Geology ,0105 earth and related environmental sciences - Abstract
co-auteur étranger; International audience; The parallel Halmahera and Sangihe arcs in eastern Indonesia are sites of active arc-arc collision of considerable interest in developing understanding of the geodynamics and geochemistry of subduction zones. Owing to the comparative remoteness of the region, few ground-based studies of the volcanoes have been undertaken. Here, we report and integrate gas measurements and (isotope) geochemical analyses of lava samples for Dukono, Ibu, Gamkonora, Gamalama, and Makian volcanoes of the Halmahera arc. Summing gas fluxes for all five volcanoes indicates arcscale emission budgets for H 2 O, CO 2 , SO 2 , H 2 S, and H 2 of 96300±27000, 2093±450, 944±400, 79±20, and 15±4 Mg/d, respectively. Dukono is the greatest source of SO 2 and H 2 , while Ibu emits the most H 2 O and H 2 S. Both Gamalama and Ibu are significant CO 2 sources. Dukono (farthest from the trench) releases the most CO 2-poor gas. Geochemical and isotopic analyses of recent ejecta emphasize the role of high fluid fluxes in the mantle wedge, necessary for partial melting of depleted mantle. Pb, Nd, and Sr isotope ratios, combined with Ba/Nd, Zr/Nd, Ba/Th, and Zr/Nb ratios, provide evidence for compositional variability along the Halmahera arc, and indicate decreasing subducted sediment contribution from south (Makian, Gamalama) to north (Gamkonora, Ibu, Dukono). Additionally, fluids formed by dehydration of altered crust become prominent at the northern volcanoes. Isotopic and Ba/Nb ratios from the Neogene and Quaternary sources compared to the current magmas further emphasize the evolution of magma genesis since the Neogene.
- Published
- 2021
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