Zircon petrochronology and mineral equilibria of the eclogites from western Tasmania: Interrogating the early Palaeozoic East Gondwana subduction record
Evidence for high-pressure metamorphism along the Cambro-Ordovician East Gondwana margin is limited to occurrences of eclogite-facies rocks in the central Transantarctic Mountains, northern Victoria Land, western Tasmania, and eastern Australia. The western Tasmanian eclogites in the Franklin Metamo...
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ftunivadelaidedl:oai:digital.library.adelaide.edu.au:2440/130982 2023-12-24T10:25:31+01:00 Zircon petrochronology and mineral equilibria of the eclogites from western Tasmania: Interrogating the early Palaeozoic East Gondwana subduction record Brown, D.A. Hand, M. Morrissey, L.J. 2021 http://hdl.handle.net/2440/130982 https://doi.org/10.1016/j.gr.2021.02.015 en eng Elsevier http://purl.org/au-research/grants/arc/DP16010437 Gondwana Research, 2021; 93:252-274 1342-937X 1878-0571 http://hdl.handle.net/2440/130982 doi:10.1016/j.gr.2021.02.015 Brown, D.A. [0000-0003-3208-8847] Hand, M. [0000-0003-3743-9706] Morrissey, L.J. [0000-0001-7506-6117] © 2021 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.gr.2021.02.015 Journal article 2021 ftunivadelaidedl https://doi.org/10.1016/j.gr.2021.02.015 2023-11-27T23:23:08Z Evidence for high-pressure metamorphism along the Cambro-Ordovician East Gondwana margin is limited to occurrences of eclogite-facies rocks in the central Transantarctic Mountains, northern Victoria Land, western Tasmania, and eastern Australia. The western Tasmanian eclogites in the Franklin Metamorphic Complex are enclosed by high-grade metapelitic lithologies and contain a high-pressure mineral assemblage of garnet + omphacitic clinopyroxene + pargasitic amphibole + phengite + quartz + rutile + clinozoisite. Mineral relationships and compositions in the eclogites, combined with mineral equilibria forward modelling, indicate the eastern margin of Tasmania was subducted along a relatively cold thermal gradient to pressures between 18 and 21.5 kbar at temperatures of 650–700 °C. LA–ICP–MS U-Pb analysis of zircon yields middle Cambrian ages, consistent with previous geochronology, as well as older Mesoproterozoic ages. Rare earth element concentrations in Cambrian-aged zircon suggest they formed at high pressures whereas Mesoproterozoic-aged zircon formed at lower pressures. Garnet preserves elemental concentrations consistent with prograde growth, with middle and heavy rare earth element concentrations resolving a complex growth history involving the consumption of clinozoisite and apatite. In-situ rutile LA–ICP–MS U-Pb ages are early to middle Cambrian and indicative of prograde to peak growth during subduction, with Zr concentrations in matrix rutile yielding upper-amphibolite-facies temperatures. In this contribution, the pressure-temperature (P–T) results for the western Tasmanian eclogites revise existing conventional thermobarometric P–T data. The updated thermal gradient information can be more precisely allied with subduction zone thermal models, which provide predictions of the thermal structure of the subduction geodynamic system. Furthermore, when integrated with the mineral equilibria and P–T data from other eclogites along the margin, these results expand upon the existing interpretations of the ... Article in Journal/Newspaper Victoria Land The University of Adelaide: Digital Library Victoria Land Transantarctic Mountains Gondwana Research 93 252 274 |
institution |
Open Polar |
collection |
The University of Adelaide: Digital Library |
op_collection_id |
ftunivadelaidedl |
language |
English |
description |
Evidence for high-pressure metamorphism along the Cambro-Ordovician East Gondwana margin is limited to occurrences of eclogite-facies rocks in the central Transantarctic Mountains, northern Victoria Land, western Tasmania, and eastern Australia. The western Tasmanian eclogites in the Franklin Metamorphic Complex are enclosed by high-grade metapelitic lithologies and contain a high-pressure mineral assemblage of garnet + omphacitic clinopyroxene + pargasitic amphibole + phengite + quartz + rutile + clinozoisite. Mineral relationships and compositions in the eclogites, combined with mineral equilibria forward modelling, indicate the eastern margin of Tasmania was subducted along a relatively cold thermal gradient to pressures between 18 and 21.5 kbar at temperatures of 650–700 °C. LA–ICP–MS U-Pb analysis of zircon yields middle Cambrian ages, consistent with previous geochronology, as well as older Mesoproterozoic ages. Rare earth element concentrations in Cambrian-aged zircon suggest they formed at high pressures whereas Mesoproterozoic-aged zircon formed at lower pressures. Garnet preserves elemental concentrations consistent with prograde growth, with middle and heavy rare earth element concentrations resolving a complex growth history involving the consumption of clinozoisite and apatite. In-situ rutile LA–ICP–MS U-Pb ages are early to middle Cambrian and indicative of prograde to peak growth during subduction, with Zr concentrations in matrix rutile yielding upper-amphibolite-facies temperatures. In this contribution, the pressure-temperature (P–T) results for the western Tasmanian eclogites revise existing conventional thermobarometric P–T data. The updated thermal gradient information can be more precisely allied with subduction zone thermal models, which provide predictions of the thermal structure of the subduction geodynamic system. Furthermore, when integrated with the mineral equilibria and P–T data from other eclogites along the margin, these results expand upon the existing interpretations of the ... |
format |
Article in Journal/Newspaper |
author |
Brown, D.A. Hand, M. Morrissey, L.J. |
spellingShingle |
Brown, D.A. Hand, M. Morrissey, L.J. Zircon petrochronology and mineral equilibria of the eclogites from western Tasmania: Interrogating the early Palaeozoic East Gondwana subduction record |
author_facet |
Brown, D.A. Hand, M. Morrissey, L.J. |
author_sort |
Brown, D.A. |
title |
Zircon petrochronology and mineral equilibria of the eclogites from western Tasmania: Interrogating the early Palaeozoic East Gondwana subduction record |
title_short |
Zircon petrochronology and mineral equilibria of the eclogites from western Tasmania: Interrogating the early Palaeozoic East Gondwana subduction record |
title_full |
Zircon petrochronology and mineral equilibria of the eclogites from western Tasmania: Interrogating the early Palaeozoic East Gondwana subduction record |
title_fullStr |
Zircon petrochronology and mineral equilibria of the eclogites from western Tasmania: Interrogating the early Palaeozoic East Gondwana subduction record |
title_full_unstemmed |
Zircon petrochronology and mineral equilibria of the eclogites from western Tasmania: Interrogating the early Palaeozoic East Gondwana subduction record |
title_sort |
zircon petrochronology and mineral equilibria of the eclogites from western tasmania: interrogating the early palaeozoic east gondwana subduction record |
publisher |
Elsevier |
publishDate |
2021 |
url |
http://hdl.handle.net/2440/130982 https://doi.org/10.1016/j.gr.2021.02.015 |
geographic |
Victoria Land Transantarctic Mountains |
geographic_facet |
Victoria Land Transantarctic Mountains |
genre |
Victoria Land |
genre_facet |
Victoria Land |
op_source |
http://dx.doi.org/10.1016/j.gr.2021.02.015 |
op_relation |
http://purl.org/au-research/grants/arc/DP16010437 Gondwana Research, 2021; 93:252-274 1342-937X 1878-0571 http://hdl.handle.net/2440/130982 doi:10.1016/j.gr.2021.02.015 Brown, D.A. [0000-0003-3208-8847] Hand, M. [0000-0003-3743-9706] Morrissey, L.J. [0000-0001-7506-6117] |
op_rights |
© 2021 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved. |
op_doi |
https://doi.org/10.1016/j.gr.2021.02.015 |
container_title |
Gondwana Research |
container_volume |
93 |
container_start_page |
252 |
op_container_end_page |
274 |
_version_ |
1786201383756627968 |