气候变化领域集成服务门户(CCPortal): Early Cretaceous bimodal volcanic rocks in the southern Lhasa terrane, south Tibet: Age, petrogenesis and tectonic implications

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DOI	10.1016/j.lithos.2016.11.016
	Early Cretaceous bimodal volcanic rocks in the southern Lhasa terrane, south Tibet: Age, petrogenesis and tectonic implications
	Wang, Chao; Ding, Lin; Liu, Zhi-Chao; Zhang, Li-Yun; Yue, Ya-Hui
通讯作者	Wang, C (通讯作者)
发表日期	2017
ISSN	0024-4937
EISSN	1872-6143
起始页码	260
结束页码	273
卷号	268
英文摘要	Limited geochronological and geochemical data from Early Cretaceous igneous rocks of the Gangdese Belt have resulted in a dispute regarding the subduction history of Neo-Tethyan Ocean. To approach this issue, we performed detailed in-situ zircon U-Pb and Hf isotopic, whole-rock elemental and Sr-Nd isotopic analyses on Late Mesozoic volcanic rocks exposed in the Liqiongda area, southern Lhasa terrane. These volcanic rocks are calc-alkaline series, dominated by basalts, basaltic andesites, and subordinate rhyolites, with a bimodal suite. The LA-ICPMS zircon U-Pb dating results of the basaltic andesites and rhyolites indicate that these volcanic rocks erupted during the Early Cretaceous (137-130 Ma). The basaltic rocks are high-alumina (average >17 wt.%), enriched in large ion lithophile elements (LILEs) and light rare earth elements (LREEs), and depleted in high field strength elements (HFSEs), showing subduction-related characteristics. They display highly positive zircon epsilon(Hf)(t) values (+10.0 to +16.3) and whole-rock epsilon(Nd)(t) values ( +5.38 to +7.47). The silicic suite is characterized by low Al2O3 (<15.4 wt.%), Mg-# (<40), and TiO2 (<03 wt.%) abundances; enriched and variable concentrations of LILEs and REEs; and strongly negative Eu anomalies (Eu/Eu* = 0.08-0.19), as well as depleted Hf isotopic compositions (epsilon(Hf)(t) = +4.9 to +16.4) and Nd isotopic compositions (epsilon(Nd)(t) = +526 to +6.71). Consequently, we envision a process of basaltic magmas similar to that of MORB extracted from a source metasomatized by slab-derived components for the petrogenesis of mafic rocks, whereas the subsequent mafic magma under plating triggered partial melting of the juvenile crust to generate acidic magma. Our results confirm the presence of Early Cretaceous volcanism in the southern Lhasa terrane. Combined with the distribution of the contemporary magmatism, deformation style, and sedimentary characteristics in the Lhasa terrane, we favor the suggestion that the Neo-Tethyan oceanic lithosphere was flat-lying beneath the Lhasa terrane during the Early Cretaceous. (C) 2016 Elsevier B.V. All rights reserved.
关键词	ZIRCON U-PB LITHOSPHERE-ASTHENOSPHERE INTERACTION HIGH-ALUMINA BASALTS TRACE-ELEMENT ISOTOPIC CONSTRAINTS GANGDESE BATHOLITH GEOCHEMICAL EVIDENCE CONTINENTAL-CRUST EARLY SUBDUCTION BASIN EVOLUTION
英文关键词	Gangdese belt; Bimodal suite; Early Cretaceous; Zircon U-Pb geochronology and Hf isotopes; Sr-Nd isotopes; Southern Lhasa terrane
语种	英语
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
WOS类目	Geochemistry & Geophysics ; Mineralogy
WOS记录号	WOS:000392680400017
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/258967
推荐引用方式 GB/T 7714	Wang, Chao,Ding, Lin,Liu, Zhi-Chao,et al. Early Cretaceous bimodal volcanic rocks in the southern Lhasa terrane, south Tibet: Age, petrogenesis and tectonic implications[J]. 中国科学院青藏高原研究所,2017,268.
APA	Wang, Chao,Ding, Lin,Liu, Zhi-Chao,Zhang, Li-Yun,&Yue, Ya-Hui.(2017).Early Cretaceous bimodal volcanic rocks in the southern Lhasa terrane, south Tibet: Age, petrogenesis and tectonic implications.LITHOS,268.
MLA	Wang, Chao,et al."Early Cretaceous bimodal volcanic rocks in the southern Lhasa terrane, south Tibet: Age, petrogenesis and tectonic implications".LITHOS 268(2017).