气候变化领域集成服务门户(CCPortal): Late Cretaceous bimodal volcanic rocks in Shuanghu induced by lithospheric delamination beneath the Southern Qiangtang, Tibet

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DOI	10.1016/j.lithos.2023.107368
	Late Cretaceous bimodal volcanic rocks in Shuanghu induced by lithospheric delamination beneath the Southern Qiangtang, Tibet
	Wen, Ding-Jun; Hu, Xiumian; Chapman, Timothy; Zeng, Gang; Ma, An-Lin; Wang, Rui-Qiang
发表日期	2023
ISSN	0024-4937
EISSN	1872-6143
卷号	460
英文摘要	The southern Qiangtang (SQT) in central Tibet is characterized by sporadic Late Cretaceous magmatic rocks whose petrogenesis and tectonic implications remain unclear. Here, new zircon U-Pb ages and Hf isotope compositions, together with whole-rock element and isotope data have been collected for the Duoma volcanic rocks from the SQT, central Tibet. Zircon U-Pb dating indicates that the Duoma volcanic rocks crystallized at ca. 98 Ma. The basalts of the Duoma volcanic rocks have low SiO2 (51.49-53.36 wt%), high total alkalis (4.65-6.25 wt%), and display OIB-like isotopic signatures (87Sr/86Sr)i = 0.7051 to 0.7058, epsilon Nd(t) = +0.04 to +1.10), overall similar to intra-plate alkali basalts. Moreover, basalts exhibit slight depletion of high-field-strength elements (HFSEs; e.g., Nb, Ta, and Ti), but enrichment of light rare earth (LaN/YbN = 6.7-7.6) with no negative Eu anomalies (Eu/Eu* = 0.91-0.99). These geochemical features, together with their high La/Nb (1.56-1.70) and Zr/Hf (44.70-45.87) but low La/Ba (0.08-0.09) and Ca/Al (0.43-0.65) ratios, suggest that the Duoma basalts originated from partial melting of garnet clinopyroxenite that was metasomatized by depleted mantle-derived melts. The coexisting rhyolites have high SiO2 (69.78-69.92 wt%) and exhibit significant enrichment in large-ion lithophile elements (LILEs) and depletion in HFSEs (Nb, Ta, and Ti). Furthermore, the Duoma rhyolites are characterized by the decoupled Nd (epsilon Nd(t) values ranging from-4.4 to-11.1) and Hf (epsilon Hf(t) values ranging from-0.7 to +2.7) compositions, that character indicates that they were probably derived from the partial melting of the lower continental crust. The compositional bimodality and heterogeneous source of the Late Cretaceous volcanism indicate that they were formed in an extension setting, presumably triggered by litho-spheric delamination beneath the SQT.
关键词	Late Cretaceous Intra-plate alkali basalts Partial melting Lithospheric delamination Southern Qiangtang
英文关键词	PARTIAL MELTING EXPERIMENTS; BANGONG-NUJIANG TETHYS; OCEAN ISLAND; TECTONIC EVOLUTION; TRACE-ELEMENT; U-PB; INTRUSIVE ROCKS; LHASA-QIANGTANG; CRUSTAL GROWTH; CARBONATITE METASOMATISM
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
WOS记录号	WOS:001088851900001
来源期刊	LITHOS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/283091
作者单位	Nanjing University; University of New England; Chengdu University of Technology
推荐引用方式 GB/T 7714	Wen, Ding-Jun,Hu, Xiumian,Chapman, Timothy,et al. Late Cretaceous bimodal volcanic rocks in Shuanghu induced by lithospheric delamination beneath the Southern Qiangtang, Tibet[J],2023,460.
APA	Wen, Ding-Jun,Hu, Xiumian,Chapman, Timothy,Zeng, Gang,Ma, An-Lin,&Wang, Rui-Qiang.(2023).Late Cretaceous bimodal volcanic rocks in Shuanghu induced by lithospheric delamination beneath the Southern Qiangtang, Tibet.LITHOS,460.
MLA	Wen, Ding-Jun,et al."Late Cretaceous bimodal volcanic rocks in Shuanghu induced by lithospheric delamination beneath the Southern Qiangtang, Tibet".LITHOS 460(2023).