@article{fdi:010053630,
  title = {{M}agma and volatile supply to post-collapse volcanism and block resurgence in {S}iwi {C}aldera ({T}anna {I}sland, {V}anuatu {A}rc)},
  author = {{M}etrich, {N}. and {A}llard, {P}. and {A}iuppa, {A}. and {B}ani, {P}hilipson and {B}ertagnini, {A}. and {S}hinohara, {H}. and {P}arello, {F}. and {D}i {M}uro, {A}. and {G}araebiti, {E}. and {B}elhadj, {O}. and {M}assare, {D}.},
  editor = {},
  language = {{ENG}},
  abstract = {{S}iwi caldera, in the {V}anuatu arc ({T}anna island), is a rare volcanic complex where both persistent eruptive activity ({Y}asur volcano) and rapid block resurgence ({Y}enkahe horst) can be investigated simultaneously during a post-caldera stage. {H}ere we provide new constraints on the feeding system of this volcanic complex, based on a detailed study of the petrology, geochemistry and volatile content of {Y}asur-{S}iwi bulk-rocks and melt inclusions, combined with measurements of the chemical composition and mass fluxes of {Y}asur volcanic gases. {M}ajor and trace element analyses of {Y}asur-{S}iwi volcanic rocks, together with literature data for other volcanic centers, point to a single magmatic series and possibly long-lived feeding of {T}anna volcanism by a homogeneous arc basalt. {O}livine-hosted melt inclusions show that the parental basaltic magma, which produces basaltic-trachyandesites to trachyandesites by similar to 50-70% crystal fractionation, is moderately enriched in volatiles (similar to 1 wt % {H}2{O}, 0 center dot 1 wt % {S} and 0 center dot 055 wt % {C}l). {T}he basaltic-trachyandesite magma, emplaced at between 4-5 km depth and the surface, preserves a high temperature (1107 +/- 15 degrees {C}) and constant {H}2{O} content (similar to 1 wt %) until very shallow depths, where it degasses extensively and crystallizes. {T}hese conditions, maintained over the past 1400 years of {Y}asur activity, require early water loss during basalt differentiation, prevalent open-system degassing, and a relatively high heat flow (similar to 10(9) {W}). {Y}asur volcano releases on average epsilon 13 center dot 4 x 10(3) tons d(-1) of {H}2{O} and 680 tons d(-1) of {SO}2, but moderate amounts of {CO}2 (840 tons d(-1)), {HC}l (165 tons d(-1)), and {HF} (23 tons d(-1)). {C}ombined with melt inclusion data, these gas outputs constrain a bulk magma degassing rate of similar to 5 x 10(7) m(3) a(-1), about a half of which is due to degassing of the basaltic-trachyandesite. {W}e compute that 25 km(3) of this magma have degassed without erupting and have accumulated beneath {S}iwi caldera over the past 1000 years, which is one order of magnitude larger than the accumulated volume uplift of the {Y}enkahe resurgent block. {H}ence, basalt supply and gradual storage of unerupted degassed basaltic-trachyandesite could easily account for (or contribute to) the {Y}enkahe block resurgence.},
  keywords = {{V}anuatu arc ; {Y}asur ; gas fluxes ; volatiles ; melt inclusions ; resurgent ; block ; volcano thermal budget},
  booktitle = {},
  journal = {{J}ournal of {P}etrology},
  volume = {52},
  numero = {6},
  pages = {1077--1105},
  ISSN = {0022-3530},
  year = {2011},
  DOI = {10.1093/petrology/egr019},
  URL = {https://www.documentation.ird.fr/hor/fdi:010053630},
}