Microstructurally controlled trace element (Zr, U–Pb) concentrations in metamorphic rutile: An example from the amphibolites of the Bergen Arcs
As a common constituent of metamorphic assemblages, rutile provides constraints on the timing and conditions of rock transformation at high resolution. However, very little is known about the links between trace element mobility and rutile microstructures that result from synmetamorphic deformation....
| Main Authors: | , , , , , , , |
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| Format: | Journal Article |
| Language: | English |
| Published: |
WILEY
2020
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| Subjects: | |
| Online Access: | https://onlinelibrary.wiley.com/doi/am-pdf/10.1111/jmg.12514 http://hdl.handle.net/20.500.11937/90011 |
| _version_ | 1848765309421355008 |
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| author | Moore, Jo Beinlich, Andreas Porter, Jennifer K. Talavera Rodriguez, Cristina Berndt, J. Piazolo, S. Austrheim, H. Putnis, Andrew |
| author_facet | Moore, Jo Beinlich, Andreas Porter, Jennifer K. Talavera Rodriguez, Cristina Berndt, J. Piazolo, S. Austrheim, H. Putnis, Andrew |
| author_sort | Moore, Jo |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | As a common constituent of metamorphic assemblages, rutile provides constraints on the timing and conditions of rock transformation at high resolution. However, very little is known about the links between trace element mobility and rutile microstructures that result from synmetamorphic deformation. To address this issue, here we combine in situ LA-ICP-MS and sensitive high-resolution ion microprobe trace element data with electron back-scatter diffraction microstructural analyses to investigate the links between rutile lattice distortions and Zr and U–Pb systematics. Furthermore, we apply this integrated approach to constrain further the temperature and timing of amphibolite facies metamorphism and deformation in the Bergen Arcs of southwestern Norway. In outcrop, the formation of porphyroblastic rutile in dynamically hydrated leucocratic domains of otherwise rutile-poor statically hydrated amphibolite provides key contextual information on both the ambient conditions of hydration and deformation and the composition of the reactive fluid. Rutile in amphibolite recorded ambient metamorphic temperatures of ~590–730°C during static hydration of the granulitic precursor. By contrast, rutile from leucocratic domains in the directly adjacent shear zone indicates that deformation was accompanied by a localized increase in temperature. These higher temperatures are recorded in strain-free rutile (~600–860°C) and by Zr concentration measurements on low-angle boundaries and shear bands (620–820°C). In addition, we also observe slight depletions of Zr and U along rutile low-angle boundaries relative to strain-free areas in deformed grains from the shear zone. This indicates that crystal–plastic deformation facilitated the compositional re-equilibration of rutile upon cooling to slightly below the peak temperature of deformation. Cessation of deformation at mid-crustal conditions near ~600°C is recorded by late stage growth of small (<150 µm) rutile in the high-strain zones. U–Pb age data obtained from the strain-free and distorted rutile grains cluster in distinct populations of 437.4 ± 2.7 Ma and c. 405–410 Ma, respectively. These different ages are interpreted to reflect the difference in closure for thermally induced Pb diffusion between undeformed and deformed rutile during post-deformation exhumation and cooling. Thus, our results provide a reconstruction of the thermochronological history of the amphibolite facies rocks of the Lindås Nappe and highlight the importance of integration of microstructural data during application of thermometers and geochronometers. |
| first_indexed | 2025-11-14T11:33:12Z |
| format | Journal Article |
| id | curtin-20.500.11937-90011 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-14T11:33:12Z |
| publishDate | 2020 |
| publisher | WILEY |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-900112023-04-26T09:02:18Z Microstructurally controlled trace element (Zr, U–Pb) concentrations in metamorphic rutile: An example from the amphibolites of the Bergen Arcs Moore, Jo Beinlich, Andreas Porter, Jennifer K. Talavera Rodriguez, Cristina Berndt, J. Piazolo, S. Austrheim, H. Putnis, Andrew Science & Technology Physical Sciences Geology amphibolite deformation microstructures high-diffusivity pathways U-Pb geochronology Zr-in-rutile thermometry FLUID-ROCK INTERACTION IN-RUTILE CLOSURE TEMPERATURE PLASTIC-DEFORMATION ICP-MS NAPIER COMPLEX MASS-TRANSFER SHEAR ZONES DIFFUSION ECLOGITE As a common constituent of metamorphic assemblages, rutile provides constraints on the timing and conditions of rock transformation at high resolution. However, very little is known about the links between trace element mobility and rutile microstructures that result from synmetamorphic deformation. To address this issue, here we combine in situ LA-ICP-MS and sensitive high-resolution ion microprobe trace element data with electron back-scatter diffraction microstructural analyses to investigate the links between rutile lattice distortions and Zr and U–Pb systematics. Furthermore, we apply this integrated approach to constrain further the temperature and timing of amphibolite facies metamorphism and deformation in the Bergen Arcs of southwestern Norway. In outcrop, the formation of porphyroblastic rutile in dynamically hydrated leucocratic domains of otherwise rutile-poor statically hydrated amphibolite provides key contextual information on both the ambient conditions of hydration and deformation and the composition of the reactive fluid. Rutile in amphibolite recorded ambient metamorphic temperatures of ~590–730°C during static hydration of the granulitic precursor. By contrast, rutile from leucocratic domains in the directly adjacent shear zone indicates that deformation was accompanied by a localized increase in temperature. These higher temperatures are recorded in strain-free rutile (~600–860°C) and by Zr concentration measurements on low-angle boundaries and shear bands (620–820°C). In addition, we also observe slight depletions of Zr and U along rutile low-angle boundaries relative to strain-free areas in deformed grains from the shear zone. This indicates that crystal–plastic deformation facilitated the compositional re-equilibration of rutile upon cooling to slightly below the peak temperature of deformation. Cessation of deformation at mid-crustal conditions near ~600°C is recorded by late stage growth of small (<150 µm) rutile in the high-strain zones. U–Pb age data obtained from the strain-free and distorted rutile grains cluster in distinct populations of 437.4 ± 2.7 Ma and c. 405–410 Ma, respectively. These different ages are interpreted to reflect the difference in closure for thermally induced Pb diffusion between undeformed and deformed rutile during post-deformation exhumation and cooling. Thus, our results provide a reconstruction of the thermochronological history of the amphibolite facies rocks of the Lindås Nappe and highlight the importance of integration of microstructural data during application of thermometers and geochronometers. 2020 Journal Article http://hdl.handle.net/20.500.11937/90011 10.1111/jmg.12514 English https://onlinelibrary.wiley.com/doi/am-pdf/10.1111/jmg.12514 http://purl.org/au-research/grants/arc/DP160103449 http://purl.org/au-research/grants/arc/LE130100053 WILEY unknown |
| spellingShingle | Science & Technology Physical Sciences Geology amphibolite deformation microstructures high-diffusivity pathways U-Pb geochronology Zr-in-rutile thermometry FLUID-ROCK INTERACTION IN-RUTILE CLOSURE TEMPERATURE PLASTIC-DEFORMATION ICP-MS NAPIER COMPLEX MASS-TRANSFER SHEAR ZONES DIFFUSION ECLOGITE Moore, Jo Beinlich, Andreas Porter, Jennifer K. Talavera Rodriguez, Cristina Berndt, J. Piazolo, S. Austrheim, H. Putnis, Andrew Microstructurally controlled trace element (Zr, U–Pb) concentrations in metamorphic rutile: An example from the amphibolites of the Bergen Arcs |
| title | Microstructurally controlled trace element (Zr, U–Pb) concentrations in metamorphic rutile: An example from the amphibolites of the Bergen Arcs |
| title_full | Microstructurally controlled trace element (Zr, U–Pb) concentrations in metamorphic rutile: An example from the amphibolites of the Bergen Arcs |
| title_fullStr | Microstructurally controlled trace element (Zr, U–Pb) concentrations in metamorphic rutile: An example from the amphibolites of the Bergen Arcs |
| title_full_unstemmed | Microstructurally controlled trace element (Zr, U–Pb) concentrations in metamorphic rutile: An example from the amphibolites of the Bergen Arcs |
| title_short | Microstructurally controlled trace element (Zr, U–Pb) concentrations in metamorphic rutile: An example from the amphibolites of the Bergen Arcs |
| title_sort | microstructurally controlled trace element (zr, u–pb) concentrations in metamorphic rutile: an example from the amphibolites of the bergen arcs |
| topic | Science & Technology Physical Sciences Geology amphibolite deformation microstructures high-diffusivity pathways U-Pb geochronology Zr-in-rutile thermometry FLUID-ROCK INTERACTION IN-RUTILE CLOSURE TEMPERATURE PLASTIC-DEFORMATION ICP-MS NAPIER COMPLEX MASS-TRANSFER SHEAR ZONES DIFFUSION ECLOGITE |
| url | https://onlinelibrary.wiley.com/doi/am-pdf/10.1111/jmg.12514 https://onlinelibrary.wiley.com/doi/am-pdf/10.1111/jmg.12514 https://onlinelibrary.wiley.com/doi/am-pdf/10.1111/jmg.12514 http://hdl.handle.net/20.500.11937/90011 |