@article{fdi:010060678,
  title = {{H}ighly explosive 2010 {M}erapi eruption : evidence for shallow-level crustal assimilation and hybrid fluid},
  author = {{B}orisova, {A}. {Y}. and {M}artel, {C}. and {G}ouy, {S}. and {P}ratomo, {I}. and {S}umarti, {S}. and {T}outain, {J}. {P}. and {B}indeman, {I}. {N}. and de {P}arseval, {P}. and {M}{\'e}taxian, {J}ean-{P}hilippe and {S}urono,},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he processes responsible for the highly explosive events at {M}erapi, {C}entral {J}ava, {I}ndonesia have been investigated through a petrological, mineralogical and geochemical study of the first-stage tephra and pyroclastic flows sampled in {O}ctober and {N}ovember 2010, and second-stage ash sampled shortly after the 5-6th {N}ovember 2010 paroxysmal subplinian eruption. {S}everal chemical and physical parameters suggest that the magma assimilated calc-silicate xenoliths derived from the surrounding carbonate-bearing crust ({J}avanese limestone). {T}he bulk volcanic samples have highly radiogenic {S}r-87/{S}r-86 (0.70571-0.70598) ratios that approach the compositional field of material similar to the calc-silicate xenoliths. {T}he 2010 plagioclase phenocrysts from the pyroclastic flow and tephra reveal anorthite cores (up to {A}n(94-97)) with low {F}e{O} contents (<= 0.8 wt.%), and {O}-18 enrichment (6.5 parts per thousand delta {O}-18). {T}he major and trace elements of the silicic glasses and phenocrysts (plagioclase, low-{A}l augite and titanomagnetite), the {S}r-isotopic compositions of the bulk samples and plagioclases erupted in 2010 can be explained by complete digestion of the 1998 and 2006 calc-silicate xenoliths. {T}he bulk assimilation proceeded through binary mixing between a calcic melt (representing {C}rustal {A}ssimilant, {C}a{O} up to 10.5 wt.% and {C}a{O}/{A}l2{O}3 up to 1.2) and the deep source hydrous {K}-rich melt {S}imilarly to the 1998 and 2006 calc-silicate xenolith composition, the 2010 {C}rustal {A}ssimilant is enriched in {M}n ({M}n{O} up to 0.5 wt.%), {Z}n, {V}, and {S}c contents. {I}n contrast, the hydrous {K}-rich melt is enriched in volatiles ({C}l up to 0.37 wt.% and bulk {H}2{O} + {CO}2 up to 5 1 wt.%), {A}l2{O}3, {T}i{O}2 and {REE} contents, consistent with its derivation from deep source. {T}his hydrous {K}-rich melt may have been saturated with an aqueous {C}l-rich fluid at about 200 {MP}a, a pressure consistent with the level of the crustal assimilation. {W}e estimated that the pre-eruptive basaltic andesite magma assimilated from 15 to 40 wt.% of the calc-silicate crustal material, corresponding to introduction of additional 0.19 to 2.1 {M}t of {CO}2 to the magma. {E}xperimental leaching of the ash samples documents the release of an aqueous fluid enriched in {C}l, {N}a, {C}a, {C}d, {S}b and {Z}n during the paroxysmal subplinian eruption. {T}he paroxysmal eruption may have been produced by saturation of the pre-eruptive basaltic andesite magma with hybrid aqueous carbonic {N}a{C}l-{HC}l-rich fluid due to bulk assimilation creating elevated partial pressure of {CO}2 at shallow crustal conditions of about 200 {MP}a. {I}n contrast, mildly explosive block-and-ash flows (typical {M}erapi-type) may result from selective assimilation of the carbonate-bearing xenoliths and lower {CO}2 partial pressure that may not lead to explosive degassing.},
  keywords = {{M}erapi volcano ; {I}ndonesia ; {S}ubplinian eruption ; {A}sh-leachate ; {M}agmatic fluid ; {D}ecarbonation reaction ; {B}ulk and selective assimilation ; {CO}2 mass and pressure ; {AFC} ; {INDONESIE} ; {JAVA}},
  booktitle = {},
  journal = {{J}ournal of {V}olcanology and {G}eothermal {R}esearch},
  volume = {261},
  numero = {{SI}},
  pages = {193--208},
  ISSN = {0377-0273},
  year = {2013},
  DOI = {10.1016/j.jvolgeores.2012.11.002},
  URL = {https://www.documentation.ird.fr/hor/fdi:010060678},
}