Wollastonite and scapolite in Precambrian calc‐silicate granulites from Australia and Antarctica
Abstract Scapolite, wollastonite, calcite, diopside, grossular‐andradite garnet and sphene occur in calc‐silicate rocks in the granulite terrain of the Arunta Block, central Australia. This assemblage buffers the CO 2 activity at a low value, so that any coexisting fluid phase must be H 2 O rich and...
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crwiley:10.1111/j.1525-1314.1987.tb00380.x 2024-06-02T07:58:19+00:00 Wollastonite and scapolite in Precambrian calc‐silicate granulites from Australia and Antarctica WARREN, R.G. HENSEN, B.J. RYBURN, R.J. 1987 http://dx.doi.org/10.1111/j.1525-1314.1987.tb00380.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1525-1314.1987.tb00380.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1525-1314.1987.tb00380.x en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Journal of Metamorphic Geology volume 5, issue 2, page 213-223 ISSN 0263-4929 1525-1314 journal-article 1987 crwiley https://doi.org/10.1111/j.1525-1314.1987.tb00380.x 2024-05-03T11:18:17Z Abstract Scapolite, wollastonite, calcite, diopside, grossular‐andradite garnet and sphene occur in calc‐silicate rocks in the granulite terrain of the Arunta Block, central Australia. This assemblage buffers the CO 2 activity at a low value, so that any coexisting fluid phase must be H 2 O rich and CO 2 poor ( X co2 = 0.2‐0.3). In contrast, the H 2 O activity in the surrounding felsic and mafic granulites was low. Thus fluid activities during granulite facies metamorphism were locally buffered in various rock units and fluid flow appears to have been restricted or fluid may have been absent. Late retrograde rims of garnet and garnet‐quartz separate phases formed in the high‐grade stage. Formation of these rims would have required either an influx of water‐rich fluid or a decrease in pressure. Evidence from the surrounding granulites shows that in one locality, the calc‐silicate rocks had undergone late isobaric hydration; in another locality, minor uplift had occurred soon after peak P‐T conditions. In both, scapolite had partly broken down to plagioclase‐calite. A calc silicate rock from the granulite terrain of Enderby Land, Antarctica, contains scapolite, wollastonite, calcite, diopside, quartz and sphene; this assemblage also indicates low CO 2 activities. In this rock, wollastonite has broken down to calcite‐quartz, to indicate isobaric cooling without influx of hydrous fluid. Article in Journal/Newspaper Antarc* Antarctica Enderby Land Wiley Online Library Journal of Metamorphic Geology 5 2 213 223 |
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English |
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Abstract Scapolite, wollastonite, calcite, diopside, grossular‐andradite garnet and sphene occur in calc‐silicate rocks in the granulite terrain of the Arunta Block, central Australia. This assemblage buffers the CO 2 activity at a low value, so that any coexisting fluid phase must be H 2 O rich and CO 2 poor ( X co2 = 0.2‐0.3). In contrast, the H 2 O activity in the surrounding felsic and mafic granulites was low. Thus fluid activities during granulite facies metamorphism were locally buffered in various rock units and fluid flow appears to have been restricted or fluid may have been absent. Late retrograde rims of garnet and garnet‐quartz separate phases formed in the high‐grade stage. Formation of these rims would have required either an influx of water‐rich fluid or a decrease in pressure. Evidence from the surrounding granulites shows that in one locality, the calc‐silicate rocks had undergone late isobaric hydration; in another locality, minor uplift had occurred soon after peak P‐T conditions. In both, scapolite had partly broken down to plagioclase‐calite. A calc silicate rock from the granulite terrain of Enderby Land, Antarctica, contains scapolite, wollastonite, calcite, diopside, quartz and sphene; this assemblage also indicates low CO 2 activities. In this rock, wollastonite has broken down to calcite‐quartz, to indicate isobaric cooling without influx of hydrous fluid. |
format |
Article in Journal/Newspaper |
author |
WARREN, R.G. HENSEN, B.J. RYBURN, R.J. |
spellingShingle |
WARREN, R.G. HENSEN, B.J. RYBURN, R.J. Wollastonite and scapolite in Precambrian calc‐silicate granulites from Australia and Antarctica |
author_facet |
WARREN, R.G. HENSEN, B.J. RYBURN, R.J. |
author_sort |
WARREN, R.G. |
title |
Wollastonite and scapolite in Precambrian calc‐silicate granulites from Australia and Antarctica |
title_short |
Wollastonite and scapolite in Precambrian calc‐silicate granulites from Australia and Antarctica |
title_full |
Wollastonite and scapolite in Precambrian calc‐silicate granulites from Australia and Antarctica |
title_fullStr |
Wollastonite and scapolite in Precambrian calc‐silicate granulites from Australia and Antarctica |
title_full_unstemmed |
Wollastonite and scapolite in Precambrian calc‐silicate granulites from Australia and Antarctica |
title_sort |
wollastonite and scapolite in precambrian calc‐silicate granulites from australia and antarctica |
publisher |
Wiley |
publishDate |
1987 |
url |
http://dx.doi.org/10.1111/j.1525-1314.1987.tb00380.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1525-1314.1987.tb00380.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1525-1314.1987.tb00380.x |
genre |
Antarc* Antarctica Enderby Land |
genre_facet |
Antarc* Antarctica Enderby Land |
op_source |
Journal of Metamorphic Geology volume 5, issue 2, page 213-223 ISSN 0263-4929 1525-1314 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1111/j.1525-1314.1987.tb00380.x |
container_title |
Journal of Metamorphic Geology |
container_volume |
5 |
container_issue |
2 |
container_start_page |
213 |
op_container_end_page |
223 |
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1800741627008909312 |