Timing of Seafloor Spreading Cessation at the Macquarie Ridge Complex (SW Pacific) and Implications for Upper Mantle Heterogeneity
Abstract 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 pr...
| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Wiley
2021-01-01
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| Series: | Geochemistry, Geophysics, Geosystems |
| Subjects: | |
| Online Access: | https://doi.org/10.1029/2020GC009485 |
| _version_ | 1797638097123409920 |
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| author | Qiang Jiang Renaud E. Merle Fred Jourdan Hugo K.H. Olierook Martin J. Whitehouse Katy A. Evans Xuan‐Ce Wang Chris E. Conway Helen C. Bostock Richard J. Wysoczanski |
| author_facet | Qiang Jiang Renaud E. Merle Fred Jourdan Hugo K.H. Olierook Martin J. Whitehouse Katy A. Evans Xuan‐Ce Wang Chris E. Conway Helen C. Bostock Richard J. Wysoczanski |
| author_sort | Qiang Jiang |
| collection | DOAJ |
| description | Abstract 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 11 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 and 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. |
| first_indexed | 2024-03-11T12:58:43Z |
| format | Article |
| id | doaj.art-9487d3e68c354fa98d22cf62f9120bef |
| institution | Directory Open Access Journal |
| issn | 1525-2027 |
| language | English |
| last_indexed | 2024-03-11T12:58:43Z |
| publishDate | 2021-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geochemistry, Geophysics, Geosystems |
| spelling | doaj.art-9487d3e68c354fa98d22cf62f9120bef2023-11-03T16:55:56ZengWileyGeochemistry, Geophysics, Geosystems1525-20272021-01-01221n/an/a10.1029/2020GC009485Timing of Seafloor Spreading Cessation at the Macquarie Ridge Complex (SW Pacific) and Implications for Upper Mantle HeterogeneityQiang Jiang0Renaud E. Merle1Fred Jourdan2Hugo K.H. Olierook3Martin J. Whitehouse4Katy A. Evans5Xuan‐Ce Wang6Chris E. Conway7Helen C. Bostock8Richard J. Wysoczanski9Western Australian Argon Isotope Facility & John de Laeter Centre Perth WA AustraliaSwedish Museum of Natural History Stockholm SwedenWestern Australian Argon Isotope Facility & John de Laeter Centre Perth WA AustraliaSchool of Earth and Planetary Sciences Curtin University Perth WA AustraliaSwedish Museum of Natural History Stockholm SwedenSchool of Earth and Planetary Sciences Curtin University Perth WA AustraliaSchool of Geoscience Yunnan University Kunming ChinaInstitute of Earthquake and Volcano Geology Geological Survey of Japan, AIST, Central 7 Ibaraki Tsukuba JapanSchool of Earth and Environmental Sciences The University of Queensland Brisbane QLD AustraliaNational Institute of Water and Atmospheric Research Wellington New ZealandAbstract 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 11 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 and 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.https://doi.org/10.1029/2020GC009485Macquarie RidgeMantle heterogeneityMORBSpreading ridgeSW Pacific |
| spellingShingle | Qiang Jiang Renaud E. Merle Fred Jourdan Hugo K.H. Olierook Martin J. Whitehouse Katy A. Evans Xuan‐Ce Wang Chris E. Conway Helen C. Bostock Richard J. Wysoczanski Timing of Seafloor Spreading Cessation at the Macquarie Ridge Complex (SW Pacific) and Implications for Upper Mantle Heterogeneity Geochemistry, Geophysics, Geosystems Macquarie Ridge Mantle heterogeneity MORB Spreading ridge SW Pacific |
| title | 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_short | 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 |
| topic | Macquarie Ridge Mantle heterogeneity MORB Spreading ridge SW Pacific |
| url | https://doi.org/10.1029/2020GC009485 |
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