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Identifying the ingredients of hydrous arc magmas: insights from Mt Lamington, Papua New Guinea.
Humphreys, M C S; Zhang, J; Cooper, G F; Macpherson, C G; Ottley, C J.
Afiliación
  • Humphreys MCS; Department of Earth Sciences, Durham University , Science Labs, Durham DH1 3LE , UK.
  • Zhang J; Department of Earth Sciences, Durham University , Science Labs, Durham DH1 3LE , UK.
  • Cooper GF; Department of Earth Sciences, Durham University , Science Labs, Durham DH1 3LE , UK.
  • Macpherson CG; Department of Earth Sciences, Durham University , Science Labs, Durham DH1 3LE , UK.
  • Ottley CJ; Department of Earth Sciences, Durham University , Science Labs, Durham DH1 3LE , UK.
Philos Trans A Math Phys Eng Sci ; 377(2139): 20180018, 2019 Feb 25.
Article en En | MEDLINE | ID: mdl-30966932
Volcanism is the surface expression of magma intrusion, crystallization, assimilation and hybridization processes operating throughout the crust over a range of time periods. Many magmas, including those erupted at subduction zones, have complex textures that reflect these processes. Here, we use textural and geochemical characteristics of calcic amphiboles to help identify multiple ingredients of subduction zone magmatism at Mt Lamington volcano, Papua New Guinea. Our approach uses existing trace element partitioning schemes to calculate the compositions of amphibole equilibrium melts (AEMs). The AEM compositions show that Mt Lamington andesites and plutonic enclaves are dominated by fractionation of amphibole + plagioclase + biotite, with assimilation of plagioclase and zircon. Magnesiohastingsite crystals in the andesite and diktytaxitic mafic enclaves reflect multiple episodes of recharge by more primitive, geochemically variable melts. The andesite also contains clots with rounded grains and melt on grain boundaries. These features indicate slow crystallization, and the retention of melt films could significantly enhance the potential for remobilization of crystals by infiltrating melts or during magma mixing. Variations in crystallization conditions could thus significantly affect the mush microstructure. We suggest that this could result in a significant bias of the volcanic record towards the preferential incorporation of more slowly cooled plutonic material from the lower crust or from more thermally mature plumbing systems. This article is part of the Theo Murphy meeting issue 'Magma reservoir architecture and dynamics'.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Tipo de estudio: Prognostic_studies Idioma: En Revista: Philos Trans A Math Phys Eng Sci Asunto de la revista: BIOFISICA / ENGENHARIA BIOMEDICA Año: 2019 Tipo del documento: Article Pais de publicación: Reino Unido
Texto completo
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XML
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Tipo de estudio: Prognostic_studies Idioma: En Revista: Philos Trans A Math Phys Eng Sci Asunto de la revista: BIOFISICA / ENGENHARIA BIOMEDICA Año: 2019 Tipo del documento: Article Pais de publicación: Reino Unido