Granulite facies metamorphism in the Mallee Bore area, northern Harts Range; implications for the thermal evolution of the eastern Arunta Inlier, central Australia

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Authors:Miller, J. A.; Cartwright, I.; Buick, I. S.
Author Affiliations:Primary:
Monash University, Department of Earth Sciences, Clayton, Victoria, Australia
Other:
University Bundoora, Australia
Volume Title:Journal of Metamorphic Geology
Source:Journal of Metamorphic Geology, 15(5), p.613-629. Publisher: Blackwell, Oxford, United Kingdom. ISSN: 0263-4929
Publication Date:1997
Note:In English. 66 refs.; illus., incl. 8 tables, geol. sketch maps
Summary:The area underwent high-T, medium- to high-P granulite-facies metamorphism. Individual geothermometers and geobarometers and average P-T calculations suggest peak metamorphic conditions were 705-810°C at 8-12 kbar. Partial melting of both metasedimentary and meta-igneous rocks, forming garnet-bearing restites, occurred under peak metamorphic conditions. Comparison with partial melting experiments suggests that vapour-absent melting in metabasic and metapelitic rocks with compositions close to those of rocks in the Mallee Bore area occurs at 800-875°C at >><[dollar]I> 9-10 kbar. The lower T obtained from the geothermometry imply that mineral compositions were reset during cooling. Following the metamorphic peak, the rocks underwent local mylonitization at 680-730°C and 5.8-7.7 kbar. After mylonitization ceased, garnet locally retrogressed to biotite, probably as a result of fluids exsolving from crystallizing melts. These three events are interpreted as different stages of a single, continuous, clockwise P-T path. The metamorphism probably occurred during the 1745-1730 m.y. late Strangways orogeny, and the area escaped significant crustal reworking during the Anmatjira and Alice Springs events that locally reached amphibolite-facies conditions elsewhere in the Harts Ranges. [P.J.T.]
Subjects:Electron probe data; Facies; Granulite facies; Metaigneous rocks; Metamorphic rocks; Metamorphism; Metasedimentary rocks; Mineral assemblages; Mylonitization; P-T conditions; P-T-t paths; Partial melting; Precambrian; Proterozoic; Regional metamorphism; Textures; Thermal history; Upper Precambrian; Arunta Block; Australasia; Australia; Harts Range; Northern Territory Australia; Strangways Orogeny
Coordinates:S232000 S225000 E1352000 E1343000
Abstract Numbers:98M/1034
Record ID:1997069213
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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