Phase Relations in Peridotitic and Pyroxenitic Rocks in the Model Systems CMASH and NCMASH
Alpine-type peridotites and associated pyroxenites are found as lenses in the continental crust in many different orogens. The reconstruction of the pressure–temperature (<rm>P</rm>–<rm>T</rm>) evolution of these rocks is, however, difficult or even impossible. With geothermo...
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fthighwire:oai:open-archive.highwire.org:petrology:41/1/69 2023-05-15T14:04:42+02:00 Phase Relations in Peridotitic and Pyroxenitic Rocks in the Model Systems CMASH and NCMASH SCHMÄDICKE, ESTHER 2000-01-01 00:00:00.0 text/html http://petrology.oxfordjournals.org/cgi/content/short/41/1/69 https://doi.org/10.1093/petrology/41.1.69 en eng Oxford University Press http://petrology.oxfordjournals.org/cgi/content/short/41/1/69 http://dx.doi.org/10.1093/petrology/41.1.69 Copyright (C) 2000, Oxford University Press ARTICLES TEXT 2000 fthighwire https://doi.org/10.1093/petrology/41.1.69 2013-05-27T17:08:03Z Alpine-type peridotites and associated pyroxenites are found as lenses in the continental crust in many different orogens. The reconstruction of the pressure–temperature (<rm>P</rm>–<rm>T</rm>) evolution of these rocks is, however, difficult or even impossible. With geothermobarometry, usually one point on the overall <rm>P</rm>–<rm>T</rm> path can be obtained. To use the different mineral assemblages observed in ultramafic rocks as <rm>P</rm>–<rm>T</rm> indicators, quantitative <rm>P</rm>–<rm>T</rm> phase diagrams are required. This study presents new calculated phase diagrams for peridotitic and pyroxenitic rocks in the model systems CaO–MgO–Al 2 O 3 –SiO 2 –H 2 O (CMASH) and Na 2 O–CaO–MgO–Al 2 O 3 –SiO 2 –H 2 O (NCMASH), which include the respective solid solutions as continuous exchange vectors. These phase diagrams represent applicable petrogenetic grids for peridotite and pyroxenite. On the basis of these general petrogenetic grids, phase diagrams for particular peridotite and pyroxenite bulk compositions are constructed. In an example of pyroxenite from the Shackleton Range, Antarctica, the different observed mineral assemblages are reflected by the phase diagrams. For these rocks, a high-pressure metamorphic stage around 18 kbar and an anticlockwise <rm>P</rm>–<rm>T</rm> evolution, not recognized previously, can be inferred. Text Antarc* Antarctica HighWire Press (Stanford University) Shackleton Shackleton Range ENVELOPE(-26.000,-26.000,-80.833,-80.833) Journal of Petrology 41 1 69 86 |
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HighWire Press (Stanford University) |
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English |
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ARTICLES |
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ARTICLES SCHMÄDICKE, ESTHER Phase Relations in Peridotitic and Pyroxenitic Rocks in the Model Systems CMASH and NCMASH |
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ARTICLES |
description |
Alpine-type peridotites and associated pyroxenites are found as lenses in the continental crust in many different orogens. The reconstruction of the pressure–temperature (<rm>P</rm>–<rm>T</rm>) evolution of these rocks is, however, difficult or even impossible. With geothermobarometry, usually one point on the overall <rm>P</rm>–<rm>T</rm> path can be obtained. To use the different mineral assemblages observed in ultramafic rocks as <rm>P</rm>–<rm>T</rm> indicators, quantitative <rm>P</rm>–<rm>T</rm> phase diagrams are required. This study presents new calculated phase diagrams for peridotitic and pyroxenitic rocks in the model systems CaO–MgO–Al 2 O 3 –SiO 2 –H 2 O (CMASH) and Na 2 O–CaO–MgO–Al 2 O 3 –SiO 2 –H 2 O (NCMASH), which include the respective solid solutions as continuous exchange vectors. These phase diagrams represent applicable petrogenetic grids for peridotite and pyroxenite. On the basis of these general petrogenetic grids, phase diagrams for particular peridotite and pyroxenite bulk compositions are constructed. In an example of pyroxenite from the Shackleton Range, Antarctica, the different observed mineral assemblages are reflected by the phase diagrams. For these rocks, a high-pressure metamorphic stage around 18 kbar and an anticlockwise <rm>P</rm>–<rm>T</rm> evolution, not recognized previously, can be inferred. |
format |
Text |
author |
SCHMÄDICKE, ESTHER |
author_facet |
SCHMÄDICKE, ESTHER |
author_sort |
SCHMÄDICKE, ESTHER |
title |
Phase Relations in Peridotitic and Pyroxenitic Rocks in the Model Systems CMASH and NCMASH |
title_short |
Phase Relations in Peridotitic and Pyroxenitic Rocks in the Model Systems CMASH and NCMASH |
title_full |
Phase Relations in Peridotitic and Pyroxenitic Rocks in the Model Systems CMASH and NCMASH |
title_fullStr |
Phase Relations in Peridotitic and Pyroxenitic Rocks in the Model Systems CMASH and NCMASH |
title_full_unstemmed |
Phase Relations in Peridotitic and Pyroxenitic Rocks in the Model Systems CMASH and NCMASH |
title_sort |
phase relations in peridotitic and pyroxenitic rocks in the model systems cmash and ncmash |
publisher |
Oxford University Press |
publishDate |
2000 |
url |
http://petrology.oxfordjournals.org/cgi/content/short/41/1/69 https://doi.org/10.1093/petrology/41.1.69 |
long_lat |
ENVELOPE(-26.000,-26.000,-80.833,-80.833) |
geographic |
Shackleton Shackleton Range |
geographic_facet |
Shackleton Shackleton Range |
genre |
Antarc* Antarctica |
genre_facet |
Antarc* Antarctica |
op_relation |
http://petrology.oxfordjournals.org/cgi/content/short/41/1/69 http://dx.doi.org/10.1093/petrology/41.1.69 |
op_rights |
Copyright (C) 2000, Oxford University Press |
op_doi |
https://doi.org/10.1093/petrology/41.1.69 |
container_title |
Journal of Petrology |
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41 |
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1 |
container_start_page |
69 |
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86 |
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1766275929775013888 |