Timing of seafloor spreading cessation at the Macquarie Ridge Complex (SW Pacific) and implications for upper mantle heterogeneity
The Macquarie Ridge Complex (MRC) on the Australia–Pacific plate boundary south of New Zealand is an extinct mid‐ocean ridge that has experienced a complex tectonic history and produced highly heterogeneous mid‐ocean ridge basalts (MORBs). When and how seafloor spreading ceased along the proto‐Macqu...
Published in: | Geochemistry, Geophysics, Geosystems |
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ftunivqespace:oai:espace.library.uq.edu.au:UQ:044854e 2023-05-15T17:09:58+02:00 Timing of seafloor spreading cessation at the Macquarie Ridge Complex (SW Pacific) and implications for upper mantle heterogeneity Jiang, Qiang Merle, Renaud E. Jourdan, Fred Olierook, Hugo K.H. Whitehouse, Martin J. Evans, Katy A. Wang, Xuan‐Ce Conway, Chris E. Bostock, Helen C. Wysoczanski, Richard J. 2020-12-21 https://espace.library.uq.edu.au/view/UQ:044854e/UQ044854e_OA.pdf https://espace.library.uq.edu.au/view/UQ:044854e eng eng Wiley-Blackwell doi:10.1029/2020gc009485 issn:1525-2027 orcid:0000-0002-8903-8958 Geochemistry and Petrology Geophysics Journal Article 2020 ftunivqespace https://doi.org/10.1029/2020gc009485 2020-12-29T01:43:53Z The Macquarie Ridge Complex (MRC) on the Australia–Pacific plate boundary south of New Zealand is an extinct mid‐ocean ridge that has experienced a complex tectonic history and produced highly heterogeneous mid‐ocean ridge basalts (MORBs). When and how seafloor spreading ceased along the proto‐Macquarie mid‐ocean ridge remain elusive, and it is unclear how the mantle source of MORBs is affected by the gradual cessation of seafloor spreading at mid‐ocean ridges. To constrain the tectonic evolution of the MRC, the mantle source variations for MORBs at dying mid‐ocean ridges, and the mechanisms of mantle enrichment and asthenospheric heterogeneities, we report eleven pyroxene, plagioclase, basaltic glass, groundmass, and sericite 40Ar/39Ar and one zircon U–Pb ages for the MRC MORBs. Our data reveal that basalts from the MRC seamounts were erupted between 25.9–1.6 Ma and Macquarie Island at ∼10 Ma. Combined age and plate reconstruction results reveal that the cessation of seafloor spreading at the MRC generally propagated from south to north along the ridge. Basalts produced by the then dying Macquarie mid‐ocean ridge at different times on different seamounts/island show a large variation in isotopic compositions and there is no clear correlation between ages and isotopic ratios. The heterogeneity of mantle source for MORBs from the proto‐Macquarie mid‐ocean ridge suggests that the upper asthenospheric mantle is heterogeneous, and such heterogeneity becomes most obvious at dying mid‐ocean ridges where the degrees of partial melting are low and a large range of melt compositions are produced. Article in Journal/Newspaper Macquarie Island The University of Queensland: UQ eSpace Pacific New Zealand Geochemistry, Geophysics, Geosystems 22 1 |
institution |
Open Polar |
collection |
The University of Queensland: UQ eSpace |
op_collection_id |
ftunivqespace |
language |
English |
topic |
Geochemistry and Petrology Geophysics |
spellingShingle |
Geochemistry and Petrology Geophysics Jiang, Qiang Merle, Renaud E. Jourdan, Fred Olierook, Hugo K.H. Whitehouse, Martin J. Evans, Katy A. Wang, Xuan‐Ce Conway, Chris E. Bostock, Helen C. Wysoczanski, Richard J. Timing of seafloor spreading cessation at the Macquarie Ridge Complex (SW Pacific) and implications for upper mantle heterogeneity |
topic_facet |
Geochemistry and Petrology Geophysics |
description |
The Macquarie Ridge Complex (MRC) on the Australia–Pacific plate boundary south of New Zealand is an extinct mid‐ocean ridge that has experienced a complex tectonic history and produced highly heterogeneous mid‐ocean ridge basalts (MORBs). When and how seafloor spreading ceased along the proto‐Macquarie mid‐ocean ridge remain elusive, and it is unclear how the mantle source of MORBs is affected by the gradual cessation of seafloor spreading at mid‐ocean ridges. To constrain the tectonic evolution of the MRC, the mantle source variations for MORBs at dying mid‐ocean ridges, and the mechanisms of mantle enrichment and asthenospheric heterogeneities, we report eleven pyroxene, plagioclase, basaltic glass, groundmass, and sericite 40Ar/39Ar and one zircon U–Pb ages for the MRC MORBs. Our data reveal that basalts from the MRC seamounts were erupted between 25.9–1.6 Ma and Macquarie Island at ∼10 Ma. Combined age and plate reconstruction results reveal that the cessation of seafloor spreading at the MRC generally propagated from south to north along the ridge. Basalts produced by the then dying Macquarie mid‐ocean ridge at different times on different seamounts/island show a large variation in isotopic compositions and there is no clear correlation between ages and isotopic ratios. The heterogeneity of mantle source for MORBs from the proto‐Macquarie mid‐ocean ridge suggests that the upper asthenospheric mantle is heterogeneous, and such heterogeneity becomes most obvious at dying mid‐ocean ridges where the degrees of partial melting are low and a large range of melt compositions are produced. |
format |
Article in Journal/Newspaper |
author |
Jiang, Qiang Merle, Renaud E. Jourdan, Fred Olierook, Hugo K.H. Whitehouse, Martin J. Evans, Katy A. Wang, Xuan‐Ce Conway, Chris E. Bostock, Helen C. Wysoczanski, Richard J. |
author_facet |
Jiang, Qiang Merle, Renaud E. Jourdan, Fred Olierook, Hugo K.H. Whitehouse, Martin J. Evans, Katy A. Wang, Xuan‐Ce Conway, Chris E. Bostock, Helen C. Wysoczanski, Richard J. |
author_sort |
Jiang, Qiang |
title |
Timing of seafloor spreading cessation at the Macquarie Ridge Complex (SW Pacific) and implications for upper mantle heterogeneity |
title_short |
Timing of seafloor spreading cessation at the Macquarie Ridge Complex (SW Pacific) and implications for upper mantle heterogeneity |
title_full |
Timing of seafloor spreading cessation at the Macquarie Ridge Complex (SW Pacific) and implications for upper mantle heterogeneity |
title_fullStr |
Timing of seafloor spreading cessation at the Macquarie Ridge Complex (SW Pacific) and implications for upper mantle heterogeneity |
title_full_unstemmed |
Timing of seafloor spreading cessation at the Macquarie Ridge Complex (SW Pacific) and implications for upper mantle heterogeneity |
title_sort |
timing of seafloor spreading cessation at the macquarie ridge complex (sw pacific) and implications for upper mantle heterogeneity |
publisher |
Wiley-Blackwell |
publishDate |
2020 |
url |
https://espace.library.uq.edu.au/view/UQ:044854e/UQ044854e_OA.pdf https://espace.library.uq.edu.au/view/UQ:044854e |
geographic |
Pacific New Zealand |
geographic_facet |
Pacific New Zealand |
genre |
Macquarie Island |
genre_facet |
Macquarie Island |
op_relation |
doi:10.1029/2020gc009485 issn:1525-2027 orcid:0000-0002-8903-8958 |
op_doi |
https://doi.org/10.1029/2020gc009485 |
container_title |
Geochemistry, Geophysics, Geosystems |
container_volume |
22 |
container_issue |
1 |
_version_ |
1766066354369069056 |