Cretaceous age, composition, and microstructure of pseudotachylyte in the Otago Schist, New Zealand
At Tucker Hill, in Central Otago, New Zealand, a series of pseudotachylyte veins are hosted in quartzofeldspathic schist. Chilled margins, microlites, flow banding, and the crystallisation of mineral phases absent from the host rock provide unequivocal evidence for melting during pseudotachylyte for...
| Main Authors: | , , , , , , |
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| Format: | Journal Article |
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SIR Publishing
2010
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| Online Access: | http://hdl.handle.net/20.500.11937/46765 |
| _version_ | 1848757651683409920 |
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| author | Barker, S. Sibson, R. Palin, J. FitzGerald, J. Reddy, Steven Warr, L. van der Pluijm, B. |
| author_facet | Barker, S. Sibson, R. Palin, J. FitzGerald, J. Reddy, Steven Warr, L. van der Pluijm, B. |
| author_sort | Barker, S. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | At Tucker Hill, in Central Otago, New Zealand, a series of pseudotachylyte veins are hosted in quartzofeldspathic schist. Chilled margins, microlites, flow banding, and the crystallisation of mineral phases absent from the host rock provide unequivocal evidence for melting during pseudotachylyte formation. Whole rock analyses of pseudotachylyte reveal c. 3 enrichment of K2O, Ba, and Rb, and similar depletion of Na2O, CaO, Sr, and Eu, as compared to host schist. Formation age of pseudotachylyte is 95.9±1.8 Ma as measured by total fusion 40Ar/39Ar analyses. Stepwise heating of pseudotachylyte matrix yields an excellently defined 40Ar/39Ar plateau age of 96.0±0.3 Ma. These well-defined ages are attributed to the presence of potassium feldspar, low abundance of inherited lithic material from the host rock, and few fluid inclusions containing extraneous Ar. We propose that formation of these pseudotachylyte veins was related to Cretaceous extensional uplift and exhumation of the Otago Schist. |
| first_indexed | 2025-11-14T09:31:29Z |
| format | Journal Article |
| id | curtin-20.500.11937-46765 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T09:31:29Z |
| publishDate | 2010 |
| publisher | SIR Publishing |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-467652017-09-13T15:58:10Z Cretaceous age, composition, and microstructure of pseudotachylyte in the Otago Schist, New Zealand Barker, S. Sibson, R. Palin, J. FitzGerald, J. Reddy, Steven Warr, L. van der Pluijm, B. pseudotachylyte geochronology Ar-Ar Otago schist friction melting At Tucker Hill, in Central Otago, New Zealand, a series of pseudotachylyte veins are hosted in quartzofeldspathic schist. Chilled margins, microlites, flow banding, and the crystallisation of mineral phases absent from the host rock provide unequivocal evidence for melting during pseudotachylyte formation. Whole rock analyses of pseudotachylyte reveal c. 3 enrichment of K2O, Ba, and Rb, and similar depletion of Na2O, CaO, Sr, and Eu, as compared to host schist. Formation age of pseudotachylyte is 95.9±1.8 Ma as measured by total fusion 40Ar/39Ar analyses. Stepwise heating of pseudotachylyte matrix yields an excellently defined 40Ar/39Ar plateau age of 96.0±0.3 Ma. These well-defined ages are attributed to the presence of potassium feldspar, low abundance of inherited lithic material from the host rock, and few fluid inclusions containing extraneous Ar. We propose that formation of these pseudotachylyte veins was related to Cretaceous extensional uplift and exhumation of the Otago Schist. 2010 Journal Article http://hdl.handle.net/20.500.11937/46765 10.1080/00288301003631764 SIR Publishing fulltext |
| spellingShingle | pseudotachylyte geochronology Ar-Ar Otago schist friction melting Barker, S. Sibson, R. Palin, J. FitzGerald, J. Reddy, Steven Warr, L. van der Pluijm, B. Cretaceous age, composition, and microstructure of pseudotachylyte in the Otago Schist, New Zealand |
| title | Cretaceous age, composition, and microstructure of pseudotachylyte in the Otago Schist, New Zealand |
| title_full | Cretaceous age, composition, and microstructure of pseudotachylyte in the Otago Schist, New Zealand |
| title_fullStr | Cretaceous age, composition, and microstructure of pseudotachylyte in the Otago Schist, New Zealand |
| title_full_unstemmed | Cretaceous age, composition, and microstructure of pseudotachylyte in the Otago Schist, New Zealand |
| title_short | Cretaceous age, composition, and microstructure of pseudotachylyte in the Otago Schist, New Zealand |
| title_sort | cretaceous age, composition, and microstructure of pseudotachylyte in the otago schist, new zealand |
| topic | pseudotachylyte geochronology Ar-Ar Otago schist friction melting |
| url | http://hdl.handle.net/20.500.11937/46765 |