DEHYDRATION MELTING AND THE GRANULITE TRANSITION IN METAPELITES FROM SOUTHERN NAMAQUALAND, SOUTH-AFRICA
In a prograde amphibolite-granulite transition zone in the Namaqualand Metamorphic Complex, metapelites show an interbanding of the amphibolite facies association biotite+sillimanite+quartz with the granulite facies association garnet+cordierite+K-feldspar. Relict graded bedding shows that compositi...
| Hlavní autoři: | , |
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| Médium: | Journal article |
| Jazyk: | English |
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Springer-Verlag
1984
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| _version_ | 1826295099033649152 |
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| author | Waters, D Whales, C |
| author_facet | Waters, D Whales, C |
| author_sort | Waters, D |
| collection | OXFORD |
| description | In a prograde amphibolite-granulite transition zone in the Namaqualand Metamorphic Complex, metapelites show an interbanding of the amphibolite facies association biotite+sillimanite+quartz with the granulite facies association garnet+cordierite+K-feldspar. Relict graded bedding shows that compositional banding is of sedimentary origin. The garnet-cordierite-K-feldspar gneisses contain quartzofeldspathic segregations surrounding garnets, and have more Fe-rich bulk compositions than the biotite-sillimanite schists. The contrasting asemblages could have formed at the same pressure and temperature provided that a(H2O) was systematically lower in the garnet-cordierite-K-feldspar layers. The a(H2O) reduction resulted from the production of silicate melt by a vapour-absent continuous Fe-Mg reaction such as biotite+sillimanite+quartz=garnet+K-feldspar+liquid which affects Fe-rich compositions before vapour-absent melting occurs in more Mg-rich rocks. The segregations represent the solid and liquid products of the reaction. Such processes imply local control of a(H2O), and indicate that this granulite transition did not result from a regional influx of metasomatising fluids. © 1984 Springer-Verlag. |
| first_indexed | 2024-03-07T03:55:53Z |
| format | Journal article |
| id | oxford-uuid:c2da535a-30c4-47ae-9b4c-55ef4206af70 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T03:55:53Z |
| publishDate | 1984 |
| publisher | Springer-Verlag |
| record_format | dspace |
| spelling | oxford-uuid:c2da535a-30c4-47ae-9b4c-55ef4206af702022-03-27T06:12:00ZDEHYDRATION MELTING AND THE GRANULITE TRANSITION IN METAPELITES FROM SOUTHERN NAMAQUALAND, SOUTH-AFRICAJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:c2da535a-30c4-47ae-9b4c-55ef4206af70EnglishSymplectic Elements at OxfordSpringer-Verlag1984Waters, DWhales, CIn a prograde amphibolite-granulite transition zone in the Namaqualand Metamorphic Complex, metapelites show an interbanding of the amphibolite facies association biotite+sillimanite+quartz with the granulite facies association garnet+cordierite+K-feldspar. Relict graded bedding shows that compositional banding is of sedimentary origin. The garnet-cordierite-K-feldspar gneisses contain quartzofeldspathic segregations surrounding garnets, and have more Fe-rich bulk compositions than the biotite-sillimanite schists. The contrasting asemblages could have formed at the same pressure and temperature provided that a(H2O) was systematically lower in the garnet-cordierite-K-feldspar layers. The a(H2O) reduction resulted from the production of silicate melt by a vapour-absent continuous Fe-Mg reaction such as biotite+sillimanite+quartz=garnet+K-feldspar+liquid which affects Fe-rich compositions before vapour-absent melting occurs in more Mg-rich rocks. The segregations represent the solid and liquid products of the reaction. Such processes imply local control of a(H2O), and indicate that this granulite transition did not result from a regional influx of metasomatising fluids. © 1984 Springer-Verlag. |
| spellingShingle | Waters, D Whales, C DEHYDRATION MELTING AND THE GRANULITE TRANSITION IN METAPELITES FROM SOUTHERN NAMAQUALAND, SOUTH-AFRICA |
| title | DEHYDRATION MELTING AND THE GRANULITE TRANSITION IN METAPELITES FROM SOUTHERN NAMAQUALAND, SOUTH-AFRICA |
| title_full | DEHYDRATION MELTING AND THE GRANULITE TRANSITION IN METAPELITES FROM SOUTHERN NAMAQUALAND, SOUTH-AFRICA |
| title_fullStr | DEHYDRATION MELTING AND THE GRANULITE TRANSITION IN METAPELITES FROM SOUTHERN NAMAQUALAND, SOUTH-AFRICA |
| title_full_unstemmed | DEHYDRATION MELTING AND THE GRANULITE TRANSITION IN METAPELITES FROM SOUTHERN NAMAQUALAND, SOUTH-AFRICA |
| title_short | DEHYDRATION MELTING AND THE GRANULITE TRANSITION IN METAPELITES FROM SOUTHERN NAMAQUALAND, SOUTH-AFRICA |
| title_sort | dehydration melting and the granulite transition in metapelites from southern namaqualand south africa |
| work_keys_str_mv | AT watersd dehydrationmeltingandthegranulitetransitioninmetapelitesfromsouthernnamaqualandsouthafrica AT whalesc dehydrationmeltingandthegranulitetransitioninmetapelitesfromsouthernnamaqualandsouthafrica |