Knowledge Management System Of Guangzhou Institute of Geochemistry，CAS
Qi, Yue1; Wang, Qiang1,2,3 ; Wei, Gang-Jian1,2; Wyman, Derek A.4; Zhang, Xiu-Zheng1,2; Dan, Wei1,2; Zhang, Le1,2; Yang, Ya-Nan1,2
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| Post-Collisional Silica-Undersaturated Bamaoqiongzong Volcanic Rocks from Northern Qiangtang: Indicators of the Mantle Heterogeneity and Geodynamic Evolution of Central Tibet | |
| Source Publication | JOURNAL OF PETROLOGY
 |
| ISSN | 0022-3530 |
| 2023 | |
| Volume | 64Issue:1Pages:24 |
| DOI | 10.1093/petrology/egac123 |
| Language | 英语 |
| WOS Research Area | Geochemistry & Geophysics |
| Abstract | The formation of post-collisional mantle-derived rocks in the Tibetan Plateau has been linked to the deep geodynamic processes that cause surface uplift. Co-existing silica-oversaturated to silica-undersaturated mantle-derived rocks have been identified in the northern Qiangtang Terrane (NQT). However, the origins of silica-undersaturated magmas are controversial, and the mechanisms responsible for variable silica activity in the mantle-derived rocks are unclear. Here, we present Ar-40/Ar-39 chronology, mineral chemistry, and whole-rock geochemical data for the Bamaoqiongzong (BMQZ) volcanic rocks of the NQT. The BMQZ volcanic rocks consist of olivine leucitites, trachybasalts, and phonolites and were erupted at ca. 29 Ma. All samples are unsaturated in silica and characterized by enrichment in light rare earth elements and large-ion lithophile elements, depletion in high-field-strength elements, and the presence of negative Nb-Ta-Ti anomalies and positive Pb anomalies. All samples show limited variation in (Sr-87/Sr-86)(i) (0.7079-0.7085) and epsilon(Nd)(t) values (-6.9 to -5.3). The geochemical compositions of the BMQZ volcanic rocks indicate that they were produced by partial melting of carbonated phlogopite-lherzolite within the lithospheric mantle. The formation of the olivine leucitites-trachybasalts-phonolites suite was controlled by fractional crystallization and magma mixing in a magmatic plumbing system. This plumbing system included several independent reservoirs and conduits within the crust. The enriched mantle sources of the BMQZ volcanic rocks were formed by the addition of carbonate-rich melts released from the southward-subducted Songpan-Ganzi Terrane after the Late Cretaceous. Our new results, together with published data, reveal systematic variations in geochemical compositions between silica-undersaturated and silica-oversaturated rocks in the NQT, which are ascribed to variations in the nature of the subducted continental materials added during intracontinental subduction. Carbonate-rich melts that were formed by the breakdown of carbonate minerals helped to generate the mantle sources of silica-undersaturated rocks, whereas silicate melts produced by the partial melting of sediment diapirs contributed to the generation of the silica-oversaturated rocks. On the basis of published numerical modelling of continental subduction and crustal deformation records in the NQT, we suggest that intracontinental subduction and lithospheric thinning together contributed to the generation of post-collisional mantle-derived rocks in the Tibetan Plateau. |
| Keyword | mantle-derived rocks northern Tibet intracontinental subduction lithospheric thinning surface uplift |
| WOS ID | WOS:000913099800001 |
| Indexed By | SCI |
| Citation statistics | |
| Document Type | 期刊论文 |
| Identifier | http://ir.gig.ac.cn/handle/344008/72385 |
| Collection | 同位素地球化学国家重点实验室 |
| Corresponding Author | Wang, Qiang |
| Affiliation | 1.Chinese Acad Sci, Guangzhou Inst Geochem, State Key Lab Isotope Geochem, Guangzhou 510640, Peoples R China 2.Chinese Acad Sci, Ctr Excellence Deep Earth Sci, Guangzhou 510640, Peoples R China 3.Univ Chinese Acad Sci, Coll Earth & Planetary Sci, Beijing 100049, Peoples R China 4.Univ Sydney, Sch Geosci, Sydney, NSW 2006, Australia |
| Recommended Citation GB/T 7714 | Qi, Yue,Wang, Qiang,Wei, Gang-Jian,et al. Post-Collisional Silica-Undersaturated Bamaoqiongzong Volcanic Rocks from Northern Qiangtang: Indicators of the Mantle Heterogeneity and Geodynamic Evolution of Central Tibet[J]. JOURNAL OF PETROLOGY,2023,64(1):24. |
| APA | Qi, Yue.,Wang, Qiang.,Wei, Gang-Jian.,Wyman, Derek A..,Zhang, Xiu-Zheng.,...&Yang, Ya-Nan.(2023).Post-Collisional Silica-Undersaturated Bamaoqiongzong Volcanic Rocks from Northern Qiangtang: Indicators of the Mantle Heterogeneity and Geodynamic Evolution of Central Tibet.JOURNAL OF PETROLOGY,64(1),24. |
| MLA | Qi, Yue,et al."Post-Collisional Silica-Undersaturated Bamaoqiongzong Volcanic Rocks from Northern Qiangtang: Indicators of the Mantle Heterogeneity and Geodynamic Evolution of Central Tibet".JOURNAL OF PETROLOGY 64.1(2023):24. |
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