Microstructural Evolution of Amphibole Peridotites in Åheim, Norway, and the Implications for Seismic Anisotropy in the Mantle Wedge
The microstructure of amphibole peridotites from Åheim, Norway were analyzed to understand the evolution of the lattice-preferred orientation (LPO) of olivine throughout the Scandian Orogeny and its implication for the seismic anisotropy of the subduction zone. The Åheim peridotites had a porphyrocl...
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MDPI AG
2020-04-01
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| Online Access: | https://www.mdpi.com/2075-163X/10/4/345 |
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| author | Sejin Jung Haemyeong Jung Håkon Austrheim |
| author_facet | Sejin Jung Haemyeong Jung Håkon Austrheim |
| author_sort | Sejin Jung |
| collection | DOAJ |
| description | The microstructure of amphibole peridotites from Åheim, Norway were analyzed to understand the evolution of the lattice-preferred orientation (LPO) of olivine throughout the Scandian Orogeny and its implication for the seismic anisotropy of the subduction zone. The Åheim peridotites had a porphyroclastic texture and some samples contained an abundant amount of hydrous minerals such as tremolite. Detailed microstructural analysis on the Åheim peridotites revealed multiple stages of deformation. The coarse grains showed an A-type LPO of olivine, which can be interpreted as the initial stage of deformation. The spinel-bearing samples showed a mixture of B-type and C-type LPOs of olivine, which is considered to represent the deformation under water-rich conditions. The recrystallized fine-grained olivine displays a B-type LPO, which can be interpreted as the final stage of deformation. Microstructures and water content of olivine indicate that the dominant deformation mechanism of olivine showing a B-type LPO is a dislocation creep under water-rich condition. The observation of the B-type LPO of olivine is important for an interpretation of trench-parallel seismic anisotropy in the mantle wedge. The calculated seismic anisotropy of the tremolite showed that tremolite can contribute to the trench-parallel seismic anisotropy in the mantle wedge. |
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| id | doaj.art-d080a500117841bbae4e9fef7ad85e87 |
| institution | Directory Open Access Journal |
| issn | 2075-163X |
| language | English |
| last_indexed | 2024-03-10T20:31:23Z |
| publishDate | 2020-04-01 |
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| spelling | doaj.art-d080a500117841bbae4e9fef7ad85e872023-11-19T21:26:02ZengMDPI AGMinerals2075-163X2020-04-0110434510.3390/min10040345Microstructural Evolution of Amphibole Peridotites in Åheim, Norway, and the Implications for Seismic Anisotropy in the Mantle WedgeSejin Jung0Haemyeong Jung1Håkon Austrheim2Tectonophysics Laboratory, School of Earth and Environmental Sciences, Seoul National University, Seoul 08826, KoreaTectonophysics Laboratory, School of Earth and Environmental Sciences, Seoul National University, Seoul 08826, KoreaThe Njord Centre, Department of Geoscience, University of Oslo, Blindern, N-0316 Oslo, NorwayThe microstructure of amphibole peridotites from Åheim, Norway were analyzed to understand the evolution of the lattice-preferred orientation (LPO) of olivine throughout the Scandian Orogeny and its implication for the seismic anisotropy of the subduction zone. The Åheim peridotites had a porphyroclastic texture and some samples contained an abundant amount of hydrous minerals such as tremolite. Detailed microstructural analysis on the Åheim peridotites revealed multiple stages of deformation. The coarse grains showed an A-type LPO of olivine, which can be interpreted as the initial stage of deformation. The spinel-bearing samples showed a mixture of B-type and C-type LPOs of olivine, which is considered to represent the deformation under water-rich conditions. The recrystallized fine-grained olivine displays a B-type LPO, which can be interpreted as the final stage of deformation. Microstructures and water content of olivine indicate that the dominant deformation mechanism of olivine showing a B-type LPO is a dislocation creep under water-rich condition. The observation of the B-type LPO of olivine is important for an interpretation of trench-parallel seismic anisotropy in the mantle wedge. The calculated seismic anisotropy of the tremolite showed that tremolite can contribute to the trench-parallel seismic anisotropy in the mantle wedge.https://www.mdpi.com/2075-163X/10/4/345microstructural evolutionlattice preferred orientationolivine in Åheimamphiboleseismic anisotropy |
| spellingShingle | Sejin Jung Haemyeong Jung Håkon Austrheim Microstructural Evolution of Amphibole Peridotites in Åheim, Norway, and the Implications for Seismic Anisotropy in the Mantle Wedge Minerals microstructural evolution lattice preferred orientation olivine in Åheim amphibole seismic anisotropy |
| title | Microstructural Evolution of Amphibole Peridotites in Åheim, Norway, and the Implications for Seismic Anisotropy in the Mantle Wedge |
| title_full | Microstructural Evolution of Amphibole Peridotites in Åheim, Norway, and the Implications for Seismic Anisotropy in the Mantle Wedge |
| title_fullStr | Microstructural Evolution of Amphibole Peridotites in Åheim, Norway, and the Implications for Seismic Anisotropy in the Mantle Wedge |
| title_full_unstemmed | Microstructural Evolution of Amphibole Peridotites in Åheim, Norway, and the Implications for Seismic Anisotropy in the Mantle Wedge |
| title_short | Microstructural Evolution of Amphibole Peridotites in Åheim, Norway, and the Implications for Seismic Anisotropy in the Mantle Wedge |
| title_sort | microstructural evolution of amphibole peridotites in aheim norway and the implications for seismic anisotropy in the mantle wedge |
| topic | microstructural evolution lattice preferred orientation olivine in Åheim amphibole seismic anisotropy |
| url | https://www.mdpi.com/2075-163X/10/4/345 |
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