| Reference Type | Journal (article/letter/editorial) |
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| Title | Anatexis and high-grade metamorphism in the Champira Dome, Malawi: petrological and Rb-Sr studies |
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| Journal | Mineralogical Magazine | ISSN | 0026-461X |
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| Authors | Haslam, H. W. | Author |
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| Brewer, M. S. | Author |
| Davis, A. E. | Author |
| Darbyshire, D. P. F. | Author |
| Year | 1980 (June) | Volume | 43 |
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| Issue | 330 |
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| Publisher | Mineralogical Society |
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| Download URL | https://rruff.info/doclib/MinMag/Volume_43/43-330-701.pdf+ |
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| DOI | doi:10.1180/minmag.1980.043.330.03Search in ResearchGate |
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| Generate Citation Formats |
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| Mindat Ref. ID | 3125 | Long-form Identifier | mindat:1:5:3125:1 |
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| GUID | 0 |
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| Full Reference | Haslam, H. W., Brewer, M. S., Davis, A. E., Darbyshire, D. P. F. (1980) Anatexis and high-grade metamorphism in the Champira Dome, Malawi: petrological and Rb-Sr studies. Mineralogical Magazine, 43 (330) 701-714 doi:10.1180/minmag.1980.043.330.03 |
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| Plain Text | Haslam, H. W., Brewer, M. S., Davis, A. E., Darbyshire, D. P. F. (1980) Anatexis and high-grade metamorphism in the Champira Dome, Malawi: petrological and Rb-Sr studies. Mineralogical Magazine, 43 (330) 701-714 doi:10.1180/minmag.1980.043.330.03 |
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| In | (1980, June) Mineralogical Magazine Vol. 43 (330) Mineralogical Society |
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| Abstract/Notes | SummaryBanded gneisses and migmatites in the Champira Dome contain assemblages of the biotite-cordierite-almandine subfacies of the granulite facies. The banded gneisses represent a sequence of arkosic sediments metamorphosed to sillimanite-cordierite gneisses. The migmatites were derived from more argillaceous and potassic sediments, with lower oxidation ratios and lower Ba/Rb ratios. They consist of a quartzo-feldspathic leucosome, representing anatectic melt, with schlieren of the refractory minerals sillimanite, garnet, biotite, and oxide minerals. Cordierite developed from garnet and biotite, except in rocks of high FeO/(FeO + MgO) ratio. Both rock types contain assemblages of magnetite + hercynite + corundum + ilmenite + hematite, formed by unmixing of high-temperature solid solutions. Rb-Sr studies of the banded gneisses gave an age of 2327 ± 25 Ma, which is interpreted as the date of metamorphism, and an initial 87Sr/86Sr ratio of 0.7064 ± 0.0003. The migmatite samples plot close to this 2327 Ma regression line, but the strontium isotopes were considerably disturbed, though not homogenized on the scale of sampling, 962 ± 34 Ma ago. It is considered that the anatexis in the migmatites was contemporaneous with the metamorphism of the banded gneisses and that the 962 ± 34 Ma event may be correlated with recrystallization of the migmatites accompanying the growth of cordierite. |
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