Phase equilibrium constraints on conditions of granulite facies metamorphism at Scourie, NW Scotland
The metamorphic evolution of a metapyroxenite and metagabbro from Scourie, NW Scotland, is investigated using phase equilibria modelled in the NCFMASHTO (Na2O–CaO–FeO–MgO–Al2O3–SiO2–H2O–TiO2–O) system. The calculated stability fields for the observed assemblages in each rock overlap and imply condit...
| Main Authors: | , |
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| Format: | Journal Article |
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Geological Society Publishing House
2011
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| Online Access: | http://hdl.handle.net/20.500.11937/42020 |
| _version_ | 1848756303468429312 |
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| author | Johnson, Tim White, R. |
| author_facet | Johnson, Tim White, R. |
| author_sort | Johnson, Tim |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | The metamorphic evolution of a metapyroxenite and metagabbro from Scourie, NW Scotland, is investigated using phase equilibria modelled in the NCFMASHTO (Na2O–CaO–FeO–MgO–Al2O3–SiO2–H2O–TiO2–O) system. The calculated stability fields for the observed assemblages in each rock overlap and imply conditions of 8.5–11.5 kbar and 875–975 °C for the peak of granulite-facies (Badcallian) metamorphism. The lack of any evidence for the former presence of garnet in the metapyroxenite suggests that the rocks cannot have reached pressures much in excess of those recorded at the metamorphic peak. The growth of coronas of plagioclase, orthopyroxene and magnetite replacing garnet in the metagabbro is consistent with near-isothermal retrograde decompression from the metamorphic peak to pressures of 7–9 kbar. The constraints on the pressure–temperature evolution imposed by the modelled phase equilibria are more consistent with a process of crustal growth dominated by magmatic accretion rather than by significant tectonic thickening during the early Scourian. |
| first_indexed | 2025-11-14T09:10:03Z |
| format | Journal Article |
| id | curtin-20.500.11937-42020 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T09:10:03Z |
| publishDate | 2011 |
| publisher | Geological Society Publishing House |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-420202017-02-28T01:39:34Z Phase equilibrium constraints on conditions of granulite facies metamorphism at Scourie, NW Scotland Johnson, Tim White, R. granulite facies metapyroxenite metagabbro Lewisian complex phase equilibria Scourie The metamorphic evolution of a metapyroxenite and metagabbro from Scourie, NW Scotland, is investigated using phase equilibria modelled in the NCFMASHTO (Na2O–CaO–FeO–MgO–Al2O3–SiO2–H2O–TiO2–O) system. The calculated stability fields for the observed assemblages in each rock overlap and imply conditions of 8.5–11.5 kbar and 875–975 °C for the peak of granulite-facies (Badcallian) metamorphism. The lack of any evidence for the former presence of garnet in the metapyroxenite suggests that the rocks cannot have reached pressures much in excess of those recorded at the metamorphic peak. The growth of coronas of plagioclase, orthopyroxene and magnetite replacing garnet in the metagabbro is consistent with near-isothermal retrograde decompression from the metamorphic peak to pressures of 7–9 kbar. The constraints on the pressure–temperature evolution imposed by the modelled phase equilibria are more consistent with a process of crustal growth dominated by magmatic accretion rather than by significant tectonic thickening during the early Scourian. 2011 Journal Article http://hdl.handle.net/20.500.11937/42020 Geological Society Publishing House restricted |
| spellingShingle | granulite facies metapyroxenite metagabbro Lewisian complex phase equilibria Scourie Johnson, Tim White, R. Phase equilibrium constraints on conditions of granulite facies metamorphism at Scourie, NW Scotland |
| title | Phase equilibrium constraints on conditions of granulite facies metamorphism at Scourie, NW Scotland |
| title_full | Phase equilibrium constraints on conditions of granulite facies metamorphism at Scourie, NW Scotland |
| title_fullStr | Phase equilibrium constraints on conditions of granulite facies metamorphism at Scourie, NW Scotland |
| title_full_unstemmed | Phase equilibrium constraints on conditions of granulite facies metamorphism at Scourie, NW Scotland |
| title_short | Phase equilibrium constraints on conditions of granulite facies metamorphism at Scourie, NW Scotland |
| title_sort | phase equilibrium constraints on conditions of granulite facies metamorphism at scourie, nw scotland |
| topic | granulite facies metapyroxenite metagabbro Lewisian complex phase equilibria Scourie |
| url | http://hdl.handle.net/20.500.11937/42020 |