气候变化领域集成服务门户(CCPortal): Geochronological and geochemical constraints on the petrogenesis of Early Eocene metagabbroic rocks in Nabang (SW Yunnan) and its implications on the Neotethyan slab subduction

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DOI	10.1016/j.gr.2014.01.007
	Geochronological and geochemical constraints on the petrogenesis of Early Eocene metagabbroic rocks in Nabang (SW Yunnan) and its implications on the Neotethyan slab subduction
	Wang, Yuejun; Li, Shubo; Ma, Liyan; Fan, Weiming; Cai, Yongfeng; Zhang, Yanhua; Zhang, Feifei
通讯作者	Wang, YJ (通讯作者)
发表日期	2015
ISSN	1342-937X
EISSN	1878-0571
起始页码	1474
结束页码	1486
卷号	27 期号:4
英文摘要	Mafic rocks similar to those of the Gangdese belt have been poorly reported in the Nabang area (SW Yunnan Province in SW China) of the Eastern Himalayan Syntaxis. This led to a widely-accepted assumption that Early Eocene mafic rocks are absent in Nabang. This paper reports new zircon U-Pb, Lu-Hf isotopic, whole-rock elemental and Sr-Nd isotopic data for the recently identified Tongbiguan and Jinzhuzhai metagabbroic plutons. Our data show that the two mafic plutons crystallized at 53.2 +/- 0.4 Ma and 53.6 +/- 0.7 Ma, respectively, with zircon in-situ epsilon(Hff)(t) values ranging from -3.1 to +4.9. Our data confirm the presence of Early Eocene mafic rocks in Nabang, contemporaneous with the major magmatic flare-ups of similar to 52 Ma in South Tibet. The rocks show high-K calc-alkaline basalt and basaltic andesite composition. They are characterized by subparallel spiky patterns with enrichment in LILEs, depletion in HFSEs and P-Ti negative anomalies. They show (Nb/La)n = 0.21-0.63, Ce/Pb = 2.99-9.91 and Nb/U = 5.2-14.1, along with high Sr-87/Sr-86(t) ratios of 0.7061-0.7077 and epsilon(Nd)(t) values of -3.4 to -5.6. Such geochemical signatures are similar to those of the synchronous Dangxung gabbroic and Yangbajing ultrapotassic rocks. Their least-contaminated samples can petrogenetically be attributed to input of slab-derived fluid into the lithospheric mantle. In conjunction with other available data, the mafic suite can be geochronologically and geochemically correlated to those in South Lhasa and are probably the equivalents of the Gangdese southeastward extension. Their formation might tectonically be related to slab rollback in response to the decreasing convergence rate. The termination of the Neotethyan subduction in SW Yunnan might be later than similar to 52 Ma, identical to that in South Tibet. (C) 2014 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.
关键词	INDIA-EURASIA COLLISION ZIRCON U-PB EASTERN HIMALAYAN SYNTAXIS TECTONIC EVOLUTION SOUTHERN TIBET GANGDESE BATHOLITH ISOTOPIC CHARACTERISTICS CONTINENTAL COLLISION VOLCANIC-ROCKS ASIA
英文关键词	Early Eocene metagabbroic rocks; Zircon U-Pb geochronology; Geochemistry; Gangdese igneous belt; West Yingjiang
语种	英语
WOS研究方向	Geology
WOS类目	Geosciences, Multidisciplinary
WOS记录号	WOS:000355024800010
来源期刊	GONDWANA RESEARCH
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/258585
推荐引用方式 GB/T 7714	Wang, Yuejun,Li, Shubo,Ma, Liyan,et al. Geochronological and geochemical constraints on the petrogenesis of Early Eocene metagabbroic rocks in Nabang (SW Yunnan) and its implications on the Neotethyan slab subduction[J]. 中国科学院青藏高原研究所,2015,27(4).
APA	Wang, Yuejun.,Li, Shubo.,Ma, Liyan.,Fan, Weiming.,Cai, Yongfeng.,...&Zhang, Feifei.(2015).Geochronological and geochemical constraints on the petrogenesis of Early Eocene metagabbroic rocks in Nabang (SW Yunnan) and its implications on the Neotethyan slab subduction.GONDWANA RESEARCH,27(4).
MLA	Wang, Yuejun,et al."Geochronological and geochemical constraints on the petrogenesis of Early Eocene metagabbroic rocks in Nabang (SW Yunnan) and its implications on the Neotethyan slab subduction".GONDWANA RESEARCH 27.4(2015).