Parkinson, I.J.; Arculus, R.J. and Eggins, S.M.
|DOI (Digital Object Identifier) Link:||http://dx.doi.org/10.1007/s00410-003-0500-z|
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Ultramafic xenoliths comprising harzburgite, lherzolite (reacted harzburgite) and spinel-rich dunite, occur in alkali olivine basalts (M series) of Grenada in the Lesser Antilles island arc. Textures are protogranular, porphyroclastic and granular; the latter are restricted to dunites and areas of the harzburgites/lherzolites where interaction with host magma has occurred. Primary mineralogy comprises olivine, orthopyroxene, clinopyroxene, and spinel. Harzburgites are residual from a fractional partial melting event totaling ~22%. Infiltration of harzburgite by (and reaction with) basalt has produced: a wehrlite, with partial dissolution of primary spinel, an increase in the oxygen fugacity (ƒO2) from primary values 1–2 log ƒO2 units above the fayalite-magnetite-quartz (FMQ) buffer, to 2–2.5 log units above the buffer; reaction of orthopyroxene to form patches of intergrown olivine and clinopyroxene, and bronzite andesite glass (60 wt%, SiO2 18–20 wt% Al2O3 and 3–4 wt% Na2O) with flat to light rare earth element-depleted, chondrite-normalized abundances. Refertilisation of the mantle by reacting melts, producing a clinopyroxene-rich lithology, may form a source of ankaramitic (high-Ca) arc basalts.
|Item Type:||Journal Article|
|Extra Information:||Some of the symbols may not have transferred correctly into this bibliographic record and/or abstract.|
|Academic Unit/Department:||Science > Environment, Earth and Ecosystems
|Interdisciplinary Research Centre:||Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)|
|Depositing User:||Users 2315 not found.|
|Date Deposited:||24 Jan 2007|
|Last Modified:||14 Jan 2016 16:21|
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