Mutual replacement reactions in alkali feldspars II: trace element partitioning and geothermometry
Perthitic alkali feldspar primocrysts in layered syenites in the Klokken intrusion in South Greenland, underwent dissolution–reprecipitation reactions in a circulating post-magmatic aqueous fluid at ~450°C, and are to a large degree pseudomorphs. These ‘mutual replacement’ reactions provide a perfec...
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ftqueensland:oai:eprints.qut.edu.au:217432 2024-02-04T10:00:56+01:00 Mutual replacement reactions in alkali feldspars II: trace element partitioning and geothermometry Parsons, Ian Magee, Charles Allen, Charlotte Shelley, J. Lee, Martin 2009 https://eprints.qut.edu.au/217432/ unknown Springer doi:10.1007/s00410-008-0358-1 Parsons, Ian, Magee, Charles, Allen, Charlotte, Shelley, J., & Lee, Martin (2009) Mutual replacement reactions in alkali feldspars II: trace element partitioning and geothermometry. Contributions to Mineralogy and Petrology, 157(5), pp. 663-687. https://eprints.qut.edu.au/217432/ Science & Engineering Faculty; School of Earth, Environmental & Biological Sciences Consult author(s) regarding copyright matters This work is covered by copyright. Unless the document is being made available under a Creative Commons Licence, you must assume that re-use is limited to personal use and that permission from the copyright owner must be obtained for all other uses. If the document is available under a Creative Commons License (or other specified license) then refer to the Licence for details of permitted re-use. It is a condition of access that users recognise and abide by the legal requirements associated with these rights. If you believe that this work infringes copyright please provide details by email to qut.copyright@qut.edu.au Contributions to Mineralogy and Petrology 2 feldspar geothermometry alkali feldspar partite partition coefficients replacement Contribution to Journal 2009 ftqueensland https://doi.org/10.1007/s00410-008-0358-1 2024-01-09T00:00:43Z Perthitic alkali feldspar primocrysts in layered syenites in the Klokken intrusion in South Greenland, underwent dissolution–reprecipitation reactions in a circulating post-magmatic aqueous fluid at ~450°C, and are to a large degree pseudomorphs. These ‘mutual replacement’ reactions provide a perfect natural experiment with which to study trace element partitioning between sodium and potassium feldspars growing simultaneously. The reactant ‘phase’ was a cryptoperthitic feldspar consisting of low albite and low microcline in a coherent sub-μm ‘braid’ intergrowth and the product phases were ‘strain-free’ incoherent subgrains of low albite and low microcline forming microporous patch perthites on scales up to 200 μm. The driving force for the reaction was reduction of coherency strain energy. The mechanisms of this process are described in Part I. Five mixed braid perthite–patch perthite crystals were analysed for major and trace elements using laser ablation-inductively coupled plasma mass spectrometry with a 19 μm beam diameter. This gave bulk analyses of the braid texture, which were in the range Ab 73–54 Or 45–27 An 4.3–0.8 , but could resolve Ab- and Or-rich patches in patch perthite. The major element bulk compositions of the crystals were retained during the replacement reactions. Major components in patches plot on tielines in the Ab–Or–An ternary system that pass through or very close to the parent braid perthite composition and indicate local equilibrium on the scale of a few tens of mm. Many trace elements, including REE, were lost to the fluid during the deuteric reactions, but the effect is large only for Fe and Ti. Cs, Pb and Sr were added to some crystals. Plots of log distribution coefficient D for Rb, Ba, Pb, Eu 2+ , La and Ce between Or- and Ab-rich patches against ionic radius are straight lines, assuming eightfold coordination, and to a first approximation are independent of ionic charge. K also lies on these lines, and the smaller ions Na and Ca lie close to them. The best linear fits were ... Article in Journal/Newspaper Greenland Queensland University of Technology: QUT ePrints Greenland Contributions to Mineralogy and Petrology 157 5 663 687 |
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Queensland University of Technology: QUT ePrints |
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ftqueensland |
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topic |
2 feldspar geothermometry alkali feldspar partite partition coefficients replacement |
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2 feldspar geothermometry alkali feldspar partite partition coefficients replacement Parsons, Ian Magee, Charles Allen, Charlotte Shelley, J. Lee, Martin Mutual replacement reactions in alkali feldspars II: trace element partitioning and geothermometry |
topic_facet |
2 feldspar geothermometry alkali feldspar partite partition coefficients replacement |
description |
Perthitic alkali feldspar primocrysts in layered syenites in the Klokken intrusion in South Greenland, underwent dissolution–reprecipitation reactions in a circulating post-magmatic aqueous fluid at ~450°C, and are to a large degree pseudomorphs. These ‘mutual replacement’ reactions provide a perfect natural experiment with which to study trace element partitioning between sodium and potassium feldspars growing simultaneously. The reactant ‘phase’ was a cryptoperthitic feldspar consisting of low albite and low microcline in a coherent sub-μm ‘braid’ intergrowth and the product phases were ‘strain-free’ incoherent subgrains of low albite and low microcline forming microporous patch perthites on scales up to 200 μm. The driving force for the reaction was reduction of coherency strain energy. The mechanisms of this process are described in Part I. Five mixed braid perthite–patch perthite crystals were analysed for major and trace elements using laser ablation-inductively coupled plasma mass spectrometry with a 19 μm beam diameter. This gave bulk analyses of the braid texture, which were in the range Ab 73–54 Or 45–27 An 4.3–0.8 , but could resolve Ab- and Or-rich patches in patch perthite. The major element bulk compositions of the crystals were retained during the replacement reactions. Major components in patches plot on tielines in the Ab–Or–An ternary system that pass through or very close to the parent braid perthite composition and indicate local equilibrium on the scale of a few tens of mm. Many trace elements, including REE, were lost to the fluid during the deuteric reactions, but the effect is large only for Fe and Ti. Cs, Pb and Sr were added to some crystals. Plots of log distribution coefficient D for Rb, Ba, Pb, Eu 2+ , La and Ce between Or- and Ab-rich patches against ionic radius are straight lines, assuming eightfold coordination, and to a first approximation are independent of ionic charge. K also lies on these lines, and the smaller ions Na and Ca lie close to them. The best linear fits were ... |
format |
Article in Journal/Newspaper |
author |
Parsons, Ian Magee, Charles Allen, Charlotte Shelley, J. Lee, Martin |
author_facet |
Parsons, Ian Magee, Charles Allen, Charlotte Shelley, J. Lee, Martin |
author_sort |
Parsons, Ian |
title |
Mutual replacement reactions in alkali feldspars II: trace element partitioning and geothermometry |
title_short |
Mutual replacement reactions in alkali feldspars II: trace element partitioning and geothermometry |
title_full |
Mutual replacement reactions in alkali feldspars II: trace element partitioning and geothermometry |
title_fullStr |
Mutual replacement reactions in alkali feldspars II: trace element partitioning and geothermometry |
title_full_unstemmed |
Mutual replacement reactions in alkali feldspars II: trace element partitioning and geothermometry |
title_sort |
mutual replacement reactions in alkali feldspars ii: trace element partitioning and geothermometry |
publisher |
Springer |
publishDate |
2009 |
url |
https://eprints.qut.edu.au/217432/ |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland |
genre_facet |
Greenland |
op_source |
Contributions to Mineralogy and Petrology |
op_relation |
doi:10.1007/s00410-008-0358-1 Parsons, Ian, Magee, Charles, Allen, Charlotte, Shelley, J., & Lee, Martin (2009) Mutual replacement reactions in alkali feldspars II: trace element partitioning and geothermometry. Contributions to Mineralogy and Petrology, 157(5), pp. 663-687. https://eprints.qut.edu.au/217432/ Science & Engineering Faculty; School of Earth, Environmental & Biological Sciences |
op_rights |
Consult author(s) regarding copyright matters This work is covered by copyright. Unless the document is being made available under a Creative Commons Licence, you must assume that re-use is limited to personal use and that permission from the copyright owner must be obtained for all other uses. If the document is available under a Creative Commons License (or other specified license) then refer to the Licence for details of permitted re-use. It is a condition of access that users recognise and abide by the legal requirements associated with these rights. If you believe that this work infringes copyright please provide details by email to qut.copyright@qut.edu.au |
op_doi |
https://doi.org/10.1007/s00410-008-0358-1 |
container_title |
Contributions to Mineralogy and Petrology |
container_volume |
157 |
container_issue |
5 |
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663 |
op_container_end_page |
687 |
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