Remnants of eoarchean continental crust derived from a subducted proto-arc
Eoarchean [3.6 to 4.0 billion years ago (Ga)] tonalite-trondhjemite-granodiorite (TTG) is the major component of Earth’s oldest remnant continental crust, thereby holding the key to understanding how continental crust originated and when plate tectonics started in the early Earth. TTGs are mostly ge...
| Main Authors: | , , , |
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| Format: | Journal Article |
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American Association for the Advancement of Science (A A A S)
2018
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| Online Access: | http://hdl.handle.net/20.500.11937/67506 |
| _version_ | 1848761583760572416 |
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| author | Ge, Rongfeng Zhu, W. Wilde, Simon Wu, H. |
| author_facet | Ge, Rongfeng Zhu, W. Wilde, Simon Wu, H. |
| author_sort | Ge, Rongfeng |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | Eoarchean [3.6 to 4.0 billion years ago (Ga)] tonalite-trondhjemite-granodiorite (TTG) is the major component of Earth’s oldest remnant continental crust, thereby holding the key to understanding how continental crust originated and when plate tectonics started in the early Earth. TTGs are mostly generated by partial melting of hydrated mafic rocks at different depths, but whether this requires subduction remains enigmatic. Recent studies show that most Archean TTGs formed at relatively low pressures (≤1.5 GPa) and do not require subduction. We report a suite of newly discovered Eoarchean tonalitic gneisses dated at ~3.7 Ga from the Tarim Craton, northwestern China. These rocks are probably the oldest high-pressure TTGs so far documented worldwide. Thermodynamic and trace element modeling demonstrates that the parent magma may have been generated by water-fluxed partial melting of moderately enriched arc-like basalts at 1.8 to 1.9 GPa and 800° to 830°C, indicating an apparent geothermal gradient (400° to 450°C GPa−1) typical for hot subduction zones. They also locally record geochemical evidence for magma interaction with a mantle wedge. Accordingly, we propose that these high-pressure TTGs were generated by partial melting of a subducted proto-arc during arc accretion. Our model implies that modern-style plate tectonics was operative, at least locally, at ~3.7 Ga and was responsible for generating some of the oldest continental nuclei. |
| first_indexed | 2025-11-14T10:33:59Z |
| format | Journal Article |
| id | curtin-20.500.11937-67506 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T10:33:59Z |
| publishDate | 2018 |
| publisher | American Association for the Advancement of Science (A A A S) |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-675062018-08-08T07:12:45Z Remnants of eoarchean continental crust derived from a subducted proto-arc Ge, Rongfeng Zhu, W. Wilde, Simon Wu, H. Eoarchean [3.6 to 4.0 billion years ago (Ga)] tonalite-trondhjemite-granodiorite (TTG) is the major component of Earth’s oldest remnant continental crust, thereby holding the key to understanding how continental crust originated and when plate tectonics started in the early Earth. TTGs are mostly generated by partial melting of hydrated mafic rocks at different depths, but whether this requires subduction remains enigmatic. Recent studies show that most Archean TTGs formed at relatively low pressures (≤1.5 GPa) and do not require subduction. We report a suite of newly discovered Eoarchean tonalitic gneisses dated at ~3.7 Ga from the Tarim Craton, northwestern China. These rocks are probably the oldest high-pressure TTGs so far documented worldwide. Thermodynamic and trace element modeling demonstrates that the parent magma may have been generated by water-fluxed partial melting of moderately enriched arc-like basalts at 1.8 to 1.9 GPa and 800° to 830°C, indicating an apparent geothermal gradient (400° to 450°C GPa−1) typical for hot subduction zones. They also locally record geochemical evidence for magma interaction with a mantle wedge. Accordingly, we propose that these high-pressure TTGs were generated by partial melting of a subducted proto-arc during arc accretion. Our model implies that modern-style plate tectonics was operative, at least locally, at ~3.7 Ga and was responsible for generating some of the oldest continental nuclei. 2018 Journal Article http://hdl.handle.net/20.500.11937/67506 10.1126/sciadv.aao3159 http://creativecommons.org/licenses/by-nc/4.0/ American Association for the Advancement of Science (A A A S) fulltext |
| spellingShingle | Ge, Rongfeng Zhu, W. Wilde, Simon Wu, H. Remnants of eoarchean continental crust derived from a subducted proto-arc |
| title | Remnants of eoarchean continental crust derived from a subducted proto-arc |
| title_full | Remnants of eoarchean continental crust derived from a subducted proto-arc |
| title_fullStr | Remnants of eoarchean continental crust derived from a subducted proto-arc |
| title_full_unstemmed | Remnants of eoarchean continental crust derived from a subducted proto-arc |
| title_short | Remnants of eoarchean continental crust derived from a subducted proto-arc |
| title_sort | remnants of eoarchean continental crust derived from a subducted proto-arc |
| url | http://hdl.handle.net/20.500.11937/67506 |