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| DOI | 10.1016/j.lithos.2014.09.029 |
| Southern Tibetan Oligocene-Miocene adakites: A record of Indian slab tearing | |
| Zhang, Li-Yun; Ducea, Mihai N.; Ding, Lin; Pullen, Alex; Kapp, Paul; Hoffman, Derek | |
| 通讯作者 | Zhang, LY (通讯作者) |
| 发表日期 | 2014 |
| ISSN | 0024-4937 |
| EISSN | 1872-6143 |
| 起始页码 | 209 |
| 结束页码 | 223 |
| 卷号 | 210 |
| 英文摘要 | Oligocene-Miocene granitoids exposed within the 1500-km-long Gangdese arc of southern Tibet exhibit adakitic compositions. Five plutonic samples from the southeastern Lhasa terrane near Namche Barwa area were analyzed to determine their geochemical characteristics and to better understand the geodynamic evolution of the eastern Himalayan syntaxis orogen. The samples, yielded U-Pb zircon ages in the range of 30-26 Ma, are intermediate to silicic in composition and have elevated K2O (1.5-8.9), Th/La ratios (0.14-1.10), low MgO (<2%) and Mg# (<50), as well as high initial Sr-87/Sr-86(i) (0.7062-0.7103) and low epsilon Nd(t) (-10.9 to -1.0) isotopic compositions. In addition, these granitic and granodioritic rocks have high Sr/Y (66-306) and La/Yb (25-312) ratios, a characteristic of adakitic rocks. In-situ zircon epsilon Hf(t) isotopic compositions are in the range of + 8.1 to -1.9. Within the framework of the Tibetan-Himalayan orogenesis we attribute these rocks to represent partial melting and mixing products of two end-member components of the lower Tibetan crust: the roots of the relatively juvenile Gangdese arc crust and newly-underplated high-potassium mafic magmas. Adakitic magmatism initiated at 30-26 Ma near the eastern Himalayan syntaxis and systematically decreases in age to the west to 18-9 Ma near Shigatse. We attribute this temporal-spatial distribution of adakitic magmatism within the Gangdese arc, along with the regional Oligo-Miocene geology, to the progressive tearing of the Indian plate. Based on the decrease in age of adakitic magmatism from east to west we hypothesize that the tear initiated beneath the eastern Himalayan syntaxis and propagated westward. (C) 2014 Elsevier B.V. All rights reserved. |
| 关键词 | ZIRCON U-PBEASTERN HIMALAYAN SYNTAXISMANTLE SOURCE CHARACTERISTICSCONTINENTAL COLLISION ZONESHF-O ISOTOPESTECTONIC EVOLUTIONASIA COLLISIONGEOCHEMICAL CONSTRAINTSGANGDESE BATHOLITHVOLCANIC-ROCKS |
| 英文关键词 | Postcollisional; Adakitic granitoids; Eastern Himalayan syntaxis; SE Tibet; Slab tearing |
| 语种 | 英语 |
| WOS研究方向 | Geochemistry & Geophysics ; Mineralogy |
| WOS类目 | Geochemistry & Geophysics ; Mineralogy |
| WOS记录号 | WOS:000347507600014 |
| 来源期刊 | LITHOS
 |
| 来源机构 | 中国科学院青藏高原研究所 |
| 文献类型 | 期刊论文 |
| 条目标识符 | http://gcip.llas.ac.cn/handle/2XKMVOVA/258365 |
| 推荐引用方式 GB/T 7714 | Zhang, Li-Yun,Ducea, Mihai N.,Ding, Lin,et al. Southern Tibetan Oligocene-Miocene adakites: A record of Indian slab tearing[J]. 中国科学院青藏高原研究所,2014,210. |
| APA | Zhang, Li-Yun,Ducea, Mihai N.,Ding, Lin,Pullen, Alex,Kapp, Paul,&Hoffman, Derek.(2014).Southern Tibetan Oligocene-Miocene adakites: A record of Indian slab tearing.LITHOS,210. |
| MLA | Zhang, Li-Yun,et al."Southern Tibetan Oligocene-Miocene adakites: A record of Indian slab tearing".LITHOS 210(2014). |
| 条目包含的文件 | 条目无相关文件。 | |||||
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