气候变化领域集成服务门户(CCPortal): Petrogenesis of Early Cretaceous volcanic rocks from the Rena-Co area in the southern Qiangtang Terrane, central Tibet: evidence from zircon U-Pb geochronology, petrochemistry and Sr-Nd-Pb-Hf isotope characteristics

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DOI	10.1017/S0016756823000274
	Petrogenesis of Early Cretaceous volcanic rocks from the Rena-Co area in the southern Qiangtang Terrane, central Tibet: evidence from zircon U-Pb geochronology, petrochemistry and Sr-Nd-Pb-Hf isotope characteristics
	Wei, Shaogang; Tang, Juxing; Song, Yang; Li, Baolong; Dong, Yujie
发表日期	2023
ISSN	0016-7568
EISSN	1469-5081
起始页码	1144
结束页码	1159
卷号	160 期号:6
英文摘要	The subduction of the Bangong-Nujiang Ocean is important in the geological evolution of the Tibetan Plateau. In this paper, we report new zircon U-Pb age and Lu-Hf isotopic data and whole-rock elemental and Sr-Nd-Pb isotopic data for Early Cretaceous dacites from the Rena-Co area (RCA) in the southern Qiangtang Terrane (QT), central Tibet and use these data to better understand the tectonic evolution of the Bangong-Nujiang suture. LA-ICP-MS dating of zircons yields ages of 109.5 +/- 0.6 Ma to 109.6 +/- 0.8 Ma for the dacites from the RCA. Geochemically, these dacites are medium-K calc-alkaline and show high SiO2 contents of 64.79-70.37 wt.%, high Sr contents of 517-598 ppm and low Y contents of 8.45-10.7 ppm, similar to those of typical adakites. Additionally, all the rocks are strongly enriched in light rare earth elements and some large ion lithophile elements (e.g. Rb, U, K and Cs) but significantly depleted in high-field-strength elements (e.g. Nb, Ta and Ti), consistent with the geochemical characteristics of arc-type magmas formed in the subduction zone. Moreover, these adakite-like dacites show whole-rock initial (Sr-87/Sr-86)(i) ratios of 0.705119 to 0.705491, (Pb-206/Pb-204)(i) ratios of 18.489 to 18.508, (Pb-207/Pb-204)(i) ratios of 15.591 to 15.612, (Pb-208/Pb-204)(i) ratios of 38.599 to 38.686, epsilon(Nd)(t) values of -0.28 to +1.25 and single-stage Nd model ages of 642 to 818 Ma, as well as significantly positive zircon epsilon(Hf)(t) values of 3.9-13.1, with young Hf-depleted mantle ages of 331 to 923 Ma. These geochemical and isotopic data indicate that they are most likely derived from the juvenile thickened mafic lower continental crust, which contains partial melts of metasomatized peridotite and subduction-related fluids in the magma source region. Based on previous studies and our new data, we propose that the RCA adakite-like dacites are most likely a result of the northwards subduction of the Bangong-Nujiang Ocean lithosphere beneath the southern QT during the Early Cretaceous and that a slab rollback model could explain the formation of the RCA adakite-like dacites.
关键词	Adakite-like dacites Petrogenesis Rena-Co area Bangong-Nujiang suture zone Tibet
英文关键词	BANGONG-NUJIANG SUTURE; FELSIC INTRUSIVE ROCKS; SLAB-DERIVED MELTS; ADAKITE-LIKE ROCKS; ISLAND-ARC MAGMA; CU-AU DEPOSIT; TECTONIC EVOLUTION; CONTINENTAL-CRUST; NORTHERN TIBET; NORTHWARD SUBDUCTION
WOS研究方向	Geosciences, Multidisciplinary
WOS记录号	WOS:000980312400001
来源期刊	GEOLOGICAL MAGAZINE
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/282933
作者单位	Changshu Institute of Technology; China Geological Survey; Chinese Academy of Geological Sciences
推荐引用方式 GB/T 7714	Wei, Shaogang,Tang, Juxing,Song, Yang,et al. Petrogenesis of Early Cretaceous volcanic rocks from the Rena-Co area in the southern Qiangtang Terrane, central Tibet: evidence from zircon U-Pb geochronology, petrochemistry and Sr-Nd-Pb-Hf isotope characteristics[J],2023,160(6).
APA	Wei, Shaogang,Tang, Juxing,Song, Yang,Li, Baolong,&Dong, Yujie.(2023).Petrogenesis of Early Cretaceous volcanic rocks from the Rena-Co area in the southern Qiangtang Terrane, central Tibet: evidence from zircon U-Pb geochronology, petrochemistry and Sr-Nd-Pb-Hf isotope characteristics.GEOLOGICAL MAGAZINE,160(6).
MLA	Wei, Shaogang,et al."Petrogenesis of Early Cretaceous volcanic rocks from the Rena-Co area in the southern Qiangtang Terrane, central Tibet: evidence from zircon U-Pb geochronology, petrochemistry and Sr-Nd-Pb-Hf isotope characteristics".GEOLOGICAL MAGAZINE 160.6(2023).