High-temperature retrogression of granulite-facies marbles from the Reynolds Range Group, central Australia; phase equilibria, isotopic resetting and fluid fluxes

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doi: 10.1093/petrology/38.7.877
Authors:Buick, Ian S.; Cartwright, Ian; Williams, Ian S.
Author Affiliations:Primary:
La Trobe University, School of Earth Sciences, Bundoora, Victoria, Australia
Other:
Monash University, Australia
Australian National University, Australia
Volume Title:Journal of Petrology
Source:Journal of Petrology, 38(7), p.877-910. Publisher: Clarendon Press, Oxford, United Kingdom. ISSN: 0022-3530
Publication Date:1997
Note:In English. 68 refs.; illus., incl. 12 tables, geol. sketch maps
Summary:The Reynolds Range group underwent granulite-facies metamorphism at 5 kbar, 750-800°C at 1600 m.y. giving calcite and dolomite marbles with diopside, forsterite, phlogopite, spinel, anorthite, K-feldspar and titanite, and then retrogression at 1590-1570 m.y. due to fluid flow in narrow strike-parallel channels producing clinohumite, tremolite, pargasite and chlorite. From equilibria under XCO2 >><[dollar]I> 0.8, resetting by water-rich fluids with XCO2 ≥ 0.02-0.03 at 3-4 kbar and 650-700°C took place, the fluids being exsolved from segregated partial melts derived from underlying metapelites. Time-integrated fluid fluxes range from 101-102m3/m2 for mineralogically reset marbles, to 103-104m3/m2 for metasomatic rocks involving permeabilities between 10-12 and 10-19m2 that vary across strike as the fluid flow was strongly channelled. Analyses of Δ18O of marbles and of interlayed metapsammites (with biotite, cordierite and orthoamphibole) and of amphiboles, Δ18O and Δ13C of carbonates and EPMA of amphiboles, forsterite, clinohumite, chlorite, clinopyroxene, spinel and clinozoisite are given. [B.E.L.]
Subjects:Facies; Fluid phase; Geochemistry; Granulite facies; High temperature; Isotope ratios; Isotopes; Marbles; Metamorphic rocks; Metamorphism; O-18/O-16; Oxygen; Phase equilibria; Retrograde metamorphism; Stable isotopes; Temperature; Australasia; Australia; Northern Territory Australia; Central Australia; Reynolds Range Group
Abstract Numbers:98M/1033
Record ID:1997064852
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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