11B-rich fluids in subduction zones: The role of antigorite dehydration in subducting slabs and boron isotope heterogeneity in the mantle
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Harvey, Jason; Garrido, Carlos J; Savov, Ivan P.; Agostini, Samuele; Padron-Navarta, Jose; Marchesi, C; Sanchez-Vizcaino, V; Gomez-Pugnaire, Maria Teresa
Description
Serpentinites form by hydration of mantle peridotite and constitute the largest potential reservoir of fluid-mobile elements entering subduction zones. Isotope ratios of one such element, boron, distinguish fluid contributions from crustal versus serpentinite sources. Despite 85% of boron hosted within abyssal peridotite being lost at the onset of subduction at the lizardite-to-antigorite transition, a sufficient cargo of boron to account for the composition of island arc magma is retained (c....[Show more]
dc.contributor.author | Harvey, Jason | |
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dc.contributor.author | Garrido, Carlos J | |
dc.contributor.author | Savov, Ivan P. | |
dc.contributor.author | Agostini, Samuele | |
dc.contributor.author | Padron-Navarta, Jose | |
dc.contributor.author | Marchesi, C | |
dc.contributor.author | Sanchez-Vizcaino, V | |
dc.contributor.author | Gomez-Pugnaire, Maria Teresa | |
dc.date.accessioned | 2016-06-14T23:20:36Z | |
dc.identifier.issn | 0009-2541 | |
dc.identifier.uri | http://hdl.handle.net/1885/103459 | |
dc.description.abstract | Serpentinites form by hydration of mantle peridotite and constitute the largest potential reservoir of fluid-mobile elements entering subduction zones. Isotope ratios of one such element, boron, distinguish fluid contributions from crustal versus serpentinite sources. Despite 85% of boron hosted within abyssal peridotite being lost at the onset of subduction at the lizardite-to-antigorite transition, a sufficient cargo of boron to account for the composition of island arc magma is retained (c. 7 μg g− 1, with a δ11B of + 22‰) until the down-going slab reaches the antigorite-out isograd. At this point a 11B-rich fluid, capable of providing the distinctive δ11B signature of island arc basalts, is released. Beyond the uniquely preserved antigorite-out isograd in serpentinites from Cerro del Almirez, Betic Cordillera, Spain, the prograde lithologies (antigorite–chlorite–orthopyroxene–olivine serpentinite, granofels-texture chlorite-harzburgite and spinifex-texture chlorite-harzburgite) have very different boron isotope signatures (δ11B = − 3 to + 6‰), but with no significant difference in boron concentration compared to the antigorite-serpentinite on the low P–T side of the isograd. 11B-rich fluid, which at least partly equilibrated with pelagic sediments, is implicated in the composition of these prograde lithologies, which dehydrated under open-system conditions. Serpentinite-hosted boron lost during the early stages of dehydration is readily incorporated into forearc peridotite. This, in turn, may be dragged to sub-arc depths as a result of subduction erosion and incorporated in a mélange comprising forearc serpentinite, altered oceanic crust and pelagic sediment. At the antigorite-out isograd it dehydrates, thus potentially providing an additional source of 11B-rich fluids. | |
dc.publisher | Elsevier | |
dc.source | Chemical Geology | |
dc.title | 11B-rich fluids in subduction zones: The role of antigorite dehydration in subducting slabs and boron isotope heterogeneity in the mantle | |
dc.type | Journal article | |
local.description.notes | Imported from ARIES | |
local.identifier.citationvolume | 376 | |
dc.date.issued | 2014 | |
local.identifier.absfor | 040300 - GEOLOGY | |
local.identifier.ariespublication | U3488905xPUB7780 | |
local.type.status | Published Version | |
local.contributor.affiliation | Harvey, Jason, University of Leeds | |
local.contributor.affiliation | Garrido, Carlos J, Universidad de Granada | |
local.contributor.affiliation | Savov, Ivan P., University of Leeds | |
local.contributor.affiliation | Agostini, Samuele, Istituto di Geoscienze e Georisorse–CNR | |
local.contributor.affiliation | Padron-Navarta, Jose, College of Physical and Mathematical Sciences, ANU | |
local.contributor.affiliation | Marchesi, C, Universidad de Granada | |
local.contributor.affiliation | Sanchez-Vizcaino, V, Universidad de Jaen | |
local.contributor.affiliation | Gomez-Pugnaire, Maria Teresa, University of Granada | |
local.description.embargo | 2037-12-31 | |
local.bibliographicCitation.startpage | 20 | |
local.bibliographicCitation.lastpage | 30 | |
local.identifier.doi | 10.1016/j.chemgeo.2014.03.015 | |
dc.date.updated | 2016-06-14T08:50:51Z | |
local.identifier.scopusID | 2-s2.0-84897931919 | |
Collections | ANU Research Publications |
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