Geochronological and geochemical results from Mesozoic basalts in southern South China Block support the flat-slab subduction model
The debate on the Mesozoic tectonics of the South China Block (SCB), featuring a broad orogenic belt and a large continental magmatic province, has been rejuvenated in the past years. There are a number of competing tectonic models, each predicting different time, space, and compositional evolutiona...
| Main Authors: | , , , , |
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| Format: | Journal Article |
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Elsevier BV
2012
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| Online Access: | http://hdl.handle.net/20.500.11937/45091 |
| _version_ | 1848757186567602176 |
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| author | Meng, L. Li, Zheng-Xiang Chen, H. Li, X. Wang, Xuan-Ce |
| author_facet | Meng, L. Li, Zheng-Xiang Chen, H. Li, X. Wang, Xuan-Ce |
| author_sort | Meng, L. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | The debate on the Mesozoic tectonics of the South China Block (SCB), featuring a broad orogenic belt and a large continental magmatic province, has been rejuvenated in the past years. There are a number of competing tectonic models, each predicting different time, space, and compositional evolutional trends for the Mesozoic igneous rocks, including sporadic basalts. In this paper, we report high precision 40Ar/39Ar ages and geochemical and Sr–Nd isotopic data for basaltic rocks in central–eastern SCB. These results, together with a data compilation, indicate three evolutionary stages for the basalts. Stage 1 (195–160 Ma) basalts occur only in inland SCB. They exhibit low initial 87Sr/86Sr ratios (0.7038 to 0.7078), high εNd(t) values (− 1.5 to 6.0) and ocean island basalt (OIB)-like geochemical characteristics such as low La/Nb ratios (0.6 to 1.4), implying negligible to minor lithosphere contamination. Stage 2 (160–110 Ma) basalts, mostly from the same inland region with minor occurrence closer to the coast, are characterized by variable initial 87Sr/86Sr ratios (0.7053 to 0.7102), εNd(t) values (− 6.0 to 5.0) and low La/Nb ratios (0.9 to 1.8), indicating an enhanced asthenosphere–lithosphere interaction. Stage 3 (110 to ≤ 80 Ma) basalts can be further divided into two sub-groups based on their geographic and geochemical variations. Basalts in the coastal regions are characterized by low εNd(t) values (− 8.1 to 3.7) and variably high La/Nb ratios (up to 4.8) indicating a strong arc signature. On the other hand, basalts in the inland regions have high εNd(t) values (− 1.9 to 6.8) and low La/Nb ratios (0.6 to 1.2) that are similar to the stage 1 basalts. We interpret these features as results of geodynamics processes related to the break-up, foundering and retreating of an early Mesozoic flat-subducted oceanic slab. |
| first_indexed | 2025-11-14T09:24:06Z |
| format | Journal Article |
| id | curtin-20.500.11937-45091 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T09:24:06Z |
| publishDate | 2012 |
| publisher | Elsevier BV |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-450912017-09-13T15:58:10Z Geochronological and geochemical results from Mesozoic basalts in southern South China Block support the flat-slab subduction model Meng, L. Li, Zheng-Xiang Chen, H. Li, X. Wang, Xuan-Ce The debate on the Mesozoic tectonics of the South China Block (SCB), featuring a broad orogenic belt and a large continental magmatic province, has been rejuvenated in the past years. There are a number of competing tectonic models, each predicting different time, space, and compositional evolutional trends for the Mesozoic igneous rocks, including sporadic basalts. In this paper, we report high precision 40Ar/39Ar ages and geochemical and Sr–Nd isotopic data for basaltic rocks in central–eastern SCB. These results, together with a data compilation, indicate three evolutionary stages for the basalts. Stage 1 (195–160 Ma) basalts occur only in inland SCB. They exhibit low initial 87Sr/86Sr ratios (0.7038 to 0.7078), high εNd(t) values (− 1.5 to 6.0) and ocean island basalt (OIB)-like geochemical characteristics such as low La/Nb ratios (0.6 to 1.4), implying negligible to minor lithosphere contamination. Stage 2 (160–110 Ma) basalts, mostly from the same inland region with minor occurrence closer to the coast, are characterized by variable initial 87Sr/86Sr ratios (0.7053 to 0.7102), εNd(t) values (− 6.0 to 5.0) and low La/Nb ratios (0.9 to 1.8), indicating an enhanced asthenosphere–lithosphere interaction. Stage 3 (110 to ≤ 80 Ma) basalts can be further divided into two sub-groups based on their geographic and geochemical variations. Basalts in the coastal regions are characterized by low εNd(t) values (− 8.1 to 3.7) and variably high La/Nb ratios (up to 4.8) indicating a strong arc signature. On the other hand, basalts in the inland regions have high εNd(t) values (− 1.9 to 6.8) and low La/Nb ratios (0.6 to 1.2) that are similar to the stage 1 basalts. We interpret these features as results of geodynamics processes related to the break-up, foundering and retreating of an early Mesozoic flat-subducted oceanic slab. 2012 Journal Article http://hdl.handle.net/20.500.11937/45091 10.1016/j.lithos.2011.11.022 Elsevier BV restricted |
| spellingShingle | Meng, L. Li, Zheng-Xiang Chen, H. Li, X. Wang, Xuan-Ce Geochronological and geochemical results from Mesozoic basalts in southern South China Block support the flat-slab subduction model |
| title | Geochronological and geochemical results from Mesozoic basalts in southern South China Block support the flat-slab subduction model |
| title_full | Geochronological and geochemical results from Mesozoic basalts in southern South China Block support the flat-slab subduction model |
| title_fullStr | Geochronological and geochemical results from Mesozoic basalts in southern South China Block support the flat-slab subduction model |
| title_full_unstemmed | Geochronological and geochemical results from Mesozoic basalts in southern South China Block support the flat-slab subduction model |
| title_short | Geochronological and geochemical results from Mesozoic basalts in southern South China Block support the flat-slab subduction model |
| title_sort | geochronological and geochemical results from mesozoic basalts in southern south china block support the flat-slab subduction model |
| url | http://hdl.handle.net/20.500.11937/45091 |