1
|
Wang X, Xiao Y, Schertl HP, Sobolev NV, Wang YY, Sun H, Jin D, Tan DB. Deep carbon cycling during subduction revealed by coexisting diamond-methane-magnesite in peridotite. Natl Sci Rev 2023; 10:nwad203. [PMID: 37671326 PMCID: PMC10476885 DOI: 10.1093/nsr/nwad203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 07/10/2023] [Indexed: 09/07/2023] Open
Abstract
Identification of multiphase inclusions in peridotite suggests that released carbon from a subducting slab can be stored as diamond+methane+magnesite in the overlying mantle wedge, achieving deep carbon cycling.
Collapse
Affiliation(s)
- Xiaoxia Wang
- CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, China
| | - Yilin Xiao
- CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, China
- CAS Center for Excellence in Comparative Planetology, China
| | - Hans-Peter Schertl
- Ruhr-University Bochum, Faculty of Geosciences, Institute of Geology, Mineralogy and Geophysics, Germany
| | - Nikolay V Sobolev
- V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of Russian Academy of Sciences, Russia
| | - Yang-Yang Wang
- CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, China
| | - He Sun
- School of Resources and Environmental Engineering, Hefei University of Technology, China
| | - Deshi Jin
- CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, China
| | - Dong-Bo Tan
- CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, China
| |
Collapse
|
2
|
Chen YX, Zhou K, He Q, Zheng YF, Schertl HP, Chen K. First finding of continental deep subduction in the Sesia Zone of Western Alps and implications for subduction dynamics. Natl Sci Rev 2023; 10:nwad023. [PMID: 37056434 PMCID: PMC10089585 DOI: 10.1093/nsr/nwad023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 01/17/2023] [Accepted: 01/19/2023] [Indexed: 01/22/2023] Open
Abstract
Abstract
Continental deep subduction after the closure of large oceanic basins is commonly ascribed to gravitational pull of the subducting oceanic slab. However, it is not clear how continental lithosphere adjacent to small oceanic basins was subducted to mantle depths. The Sesia Zone in the Western Alps provides an excellent target for exploration of subduction dynamics in such a tectonic setting. Here we report the first finding of coesite in a jadeite-bearing orthogneiss from the Sesia Zone, providing the first evidence for deep subduction of the continental crust to mantle depths for ultrahigh-pressure (UHP) metamorphism in this zone. Three coesite inclusions were identified by laser Raman spectroscopy in two garnet grains. Based on zircon U-Pb dating and trace element analysis, the UHP metamorphic age was constrained to be 76.0 ± 1.0 Ma. The phase equilibrium modelling yields peak metamorphic pressures of 2.8-3.3 GPa, demonstrating the continental deep subduction to mantle depths of >80 km. The subducted continental crust was a rifted hyperextended continental margin, which was converted to the passive continental margin during seafloor spreading and then deeply subducted during the oblique convergence between Adria microplate and Eurasian plate in the Late Cretaceous. Because the slab pull could only play a limited role in closing small oceanic basins for continental collision, the distal push of either continental breakup or seafloor spreading is suggested as the major driving force for the deep subduction of continental crust in the Western Alps. Therefore, deep subduction of the continental crust bordering small oceanic basins would be induced by the far-field stress of compression, whereas that bordering large oceanic basins was spontaneous due to the oceanic slab pull. This provides a new insight into the geodynamic mechanism of continental deep subduction.
Collapse
Affiliation(s)
- Yi-Xiang Chen
- CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China , Hefei 230026 , China
- Center of Excellence for Comparative Planetology, Chinese Academy of Sciences (CAS) , Hefei 230026 , China
| | - Kun Zhou
- CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China , Hefei 230026 , China
| | - Qiang He
- CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China , Hefei 230026 , China
| | - Yong-Fei Zheng
- CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China , Hefei 230026 , China
- Center of Excellence for Comparative Planetology, Chinese Academy of Sciences (CAS) , Hefei 230026 , China
| | - Hans-Peter Schertl
- Institute of Geology, Mineralogy and Geophysics, Faculty of Geosciences, Ruhr University Bochum , 44780 Bochum , Germany
| | - Kun Chen
- CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China , Hefei 230026 , China
| |
Collapse
|