Crystallization and textural evolution of a closed-system magma chamber: insights from a crystal size distribution study of the Lilloise layered intrusion, East Greenland
Abstract The recognition that postcumulus processes significantly modify primary textures in layered mafic intrusions has thrown into question many early observations on which classical crystallization theories are based. Petrographic observations combined with quantitative textural analysis of samp...
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crcambridgeupr:10.1017/s0016756809990689 2024-05-19T07:39:35+00:00 Crystallization and textural evolution of a closed-system magma chamber: insights from a crystal size distribution study of the Lilloise layered intrusion, East Greenland MAGEE, C. O'DRISCOLL, B. CHAMBERS, A. D. 2010 http://dx.doi.org/10.1017/s0016756809990689 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0016756809990689 en eng Cambridge University Press (CUP) https://www.cambridge.org/core/terms Geological Magazine volume 147, issue 3, page 363-379 ISSN 0016-7568 1469-5081 journal-article 2010 crcambridgeupr https://doi.org/10.1017/s0016756809990689 2024-04-25T06:51:23Z Abstract The recognition that postcumulus processes significantly modify primary textures in layered mafic intrusions has thrown into question many early observations on which classical crystallization theories are based. Petrographic observations combined with quantitative textural analysis of samples from various stratigraphic levels of the Lilloise intrusion, East Greenland, demonstrate that postcumulus textural modification of cumulates, formed during the solidification of a closed system magma chamber, may be detected. Crystal size distribution (CSD) measurements of Lilloise cumulates and the resulting CSD profiles are compared to predicted theoretical closed system CSD profiles. Similarities between the measured CSD profiles and published predicted CSD profiles support Lilloise magma evolving in a closed system chamber and indicate that primary crystallization processes can be distinguished using quantitative textural techniques. Textural coarsening driven by syn-magmatic deformation is suggested to be the dominant postcumulus process affecting CSD plot morphology. CSD slope values and profiles (plot shapes) remain relatively constant for a given liquidus mineral (particularly olivine and clinopyroxene), so that the number of phases on the liquidus at any one time affects mineral modal abundances. As a result, CSDs generally exhibit overall smaller grainsizes and progressively lower nucleation densities at higher levels in the intrusion. Article in Journal/Newspaper East Greenland Greenland Cambridge University Press Geological Magazine 147 3 363 379 |
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Abstract The recognition that postcumulus processes significantly modify primary textures in layered mafic intrusions has thrown into question many early observations on which classical crystallization theories are based. Petrographic observations combined with quantitative textural analysis of samples from various stratigraphic levels of the Lilloise intrusion, East Greenland, demonstrate that postcumulus textural modification of cumulates, formed during the solidification of a closed system magma chamber, may be detected. Crystal size distribution (CSD) measurements of Lilloise cumulates and the resulting CSD profiles are compared to predicted theoretical closed system CSD profiles. Similarities between the measured CSD profiles and published predicted CSD profiles support Lilloise magma evolving in a closed system chamber and indicate that primary crystallization processes can be distinguished using quantitative textural techniques. Textural coarsening driven by syn-magmatic deformation is suggested to be the dominant postcumulus process affecting CSD plot morphology. CSD slope values and profiles (plot shapes) remain relatively constant for a given liquidus mineral (particularly olivine and clinopyroxene), so that the number of phases on the liquidus at any one time affects mineral modal abundances. As a result, CSDs generally exhibit overall smaller grainsizes and progressively lower nucleation densities at higher levels in the intrusion. |
format |
Article in Journal/Newspaper |
author |
MAGEE, C. O'DRISCOLL, B. CHAMBERS, A. D. |
spellingShingle |
MAGEE, C. O'DRISCOLL, B. CHAMBERS, A. D. Crystallization and textural evolution of a closed-system magma chamber: insights from a crystal size distribution study of the Lilloise layered intrusion, East Greenland |
author_facet |
MAGEE, C. O'DRISCOLL, B. CHAMBERS, A. D. |
author_sort |
MAGEE, C. |
title |
Crystallization and textural evolution of a closed-system magma chamber: insights from a crystal size distribution study of the Lilloise layered intrusion, East Greenland |
title_short |
Crystallization and textural evolution of a closed-system magma chamber: insights from a crystal size distribution study of the Lilloise layered intrusion, East Greenland |
title_full |
Crystallization and textural evolution of a closed-system magma chamber: insights from a crystal size distribution study of the Lilloise layered intrusion, East Greenland |
title_fullStr |
Crystallization and textural evolution of a closed-system magma chamber: insights from a crystal size distribution study of the Lilloise layered intrusion, East Greenland |
title_full_unstemmed |
Crystallization and textural evolution of a closed-system magma chamber: insights from a crystal size distribution study of the Lilloise layered intrusion, East Greenland |
title_sort |
crystallization and textural evolution of a closed-system magma chamber: insights from a crystal size distribution study of the lilloise layered intrusion, east greenland |
publisher |
Cambridge University Press (CUP) |
publishDate |
2010 |
url |
http://dx.doi.org/10.1017/s0016756809990689 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0016756809990689 |
genre |
East Greenland Greenland |
genre_facet |
East Greenland Greenland |
op_source |
Geological Magazine volume 147, issue 3, page 363-379 ISSN 0016-7568 1469-5081 |
op_rights |
https://www.cambridge.org/core/terms |
op_doi |
https://doi.org/10.1017/s0016756809990689 |
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Geological Magazine |
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147 |
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3 |
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363 |
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379 |
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1799479167442485248 |