Eocene rhyolites in the Shanglaxiu-Xialaxiu area of north-eastern Qiangtang Block, Tibet: Partial melting of juvenile crust?
文献类型：期刊论文
| 作者 | Wei, Yi-Wen1,4; Wang, Jun1; Wang, Qiang1,4; Wang, Bing-Zhang3; Kerr, Andrew C.2; Li, Wu-Fu3; Li, Shan-Ping3; Liu, Jin-Heng1; Wang, Chun-Tao3; Wang, Zi-Long1 |
| 刊名 | LITHOS
 |
| 出版日期 | 2024-07-01 |
| 卷号 | 476页码:16 |
| 关键词 | Rhyolites Juvenile crust Continental subduction Eocene Qiangtang Tibet |
| ISSN号 | 0024-4937 |
| DOI | 10.1016/j.lithos.2024.107594 |
| 英文摘要 | Many granitoids and their eruptive equivalents are substantially derived from the uppermost proportion of continental crust, and so their petrogenesis and source are significant in understanding the evolution and characteristics of continental crust. The Eocene felsic rocks in the Qiangtang block (central Tibet) commonly have enriched Nd isotope compositions and have been considered to be related to the recycling of ancient continental crustal material. In this paper we report new data on early Eocene felsic rocks with positive e Nd values in the northeastern Qiangtang block, which can be used to help understand Cenozoic evolution and characteristics of continental crust in the Qiangtang block. These rocks consist of rhyolites and occur in the Shanglaxiu and Xialaxiu areas in the north-eastern Qiangtang block. Zircon U-Pb dating yields ages of 47.8 0.6 and 44.2 +/- 0.7 Ma for the Shanglaxiu and Xialaxiu rhyolites, respectively, and so they represent the earliest record of Eocene magmatism in the Qiangtang block. The Shanglaxiu-Xialaxiu rhyolites have relatively low calculated zircon saturation temperatures (719-819 degrees C), along with high SiO 2 (74.8-83.3 wt%) and K 2 (5.1-7.8 wt%) contents, and low MgO (0.2-0.3 wt%), Cr and Ni contents. They are enriched in light rare earth elements (LREEs), Rb, K, Th, Zr, and Hf, and are depleted in Nb, Ta, Ti, Sr, and P, with moderately negative Eu anomalies. The Shanglaxiu rhyolites have positive whole-rock e Nd (t) (0.3-0.4) and zircon e Hf (t) (1.8-10.4), and variable zircon 8 18 O (6.3-7.3%o). The Xialaxiu rhyolites have slightly different whole-rock e Nd (t) (-1.5 to -1.6), but similar zircon e Hf (t) (2.2-7.7) and 8 18 O (6.7-7.2%o). We propose that the Shanglaxiu-Xialaxiu rhyolites were most probably generated by partial melting of the pre-existing juvenile crust with the addition of minor sedimentary material. This partial melting was possibly triggered by the south-dipping continental subduction of the Songpan-Ganzi block. The pre-existing juvenile crust was probably formed during the subduction of Paleo-Tethyan oceanic slab in Paleozoic-Early Mesozoic. |
| WOS研究方向 | Geochemistry & Geophysics ; Mineralogy |
| 语种 | 英语 |
| WOS记录号 | WOS:001218552800001 |
| 源URL | [http://ir.gig.ac.cn/handle/344008/77003]  |
| 专题 | 同位素地球化学国家重点实验室 |
| 通讯作者 | Wang, Qiang |
| 作者单位 | 1.Chinese Acad Sci, State Key Lab Isotope Geochem, Guangzhou Inst Geochem, Guangzhou 510640, Peoples R China 2.Cardiff Univ, Sch Earth & Environm Sci, Cardiff CF10 3AT, Wales 3.Qinghai Geol Survey Inst, Xining 810012, Qinghai, Peoples R China 4.Univ Chinese Acad Sci, Coll Earth & Planetary Sci, Beijing 100049, Peoples R China |
| 推荐引用方式 GB/T 7714 | Wei, Yi-Wen,Wang, Jun,Wang, Qiang,et al. Eocene rhyolites in the Shanglaxiu-Xialaxiu area of north-eastern Qiangtang Block, Tibet: Partial melting of juvenile crust?[J]. LITHOS,2024,476:16. |
| APA | Wei, Yi-Wen.,Wang, Jun.,Wang, Qiang.,Wang, Bing-Zhang.,Kerr, Andrew C..,...&Wang, Zi-Long.(2024).Eocene rhyolites in the Shanglaxiu-Xialaxiu area of north-eastern Qiangtang Block, Tibet: Partial melting of juvenile crust?.LITHOS,476,16. |
| MLA | Wei, Yi-Wen,et al."Eocene rhyolites in the Shanglaxiu-Xialaxiu area of north-eastern Qiangtang Block, Tibet: Partial melting of juvenile crust?".LITHOS 476(2024):16. |
入库方式： OAI收割
来源：广州地球化学研究所
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