气候变化领域集成服务门户(CCPortal): Prolonged Neo-Tethyan magmatic arc in Myanmar: evidence from geochemistry and Sr-Nd-Hf isotopes of Cretaceous mafic-felsic intrusions in the Banmauk-Kawlin area

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DOI	10.1007/s00531-020-01824-w
	Prolonged Neo-Tethyan magmatic arc in Myanmar: evidence from geochemistry and Sr-Nd-Hf isotopes of Cretaceous mafic-felsic intrusions in the Banmauk-Kawlin area
	Li, Jin-Xiang; Fan, Wei-Ming; Zhang, Li-Yun; Peng, Tou-Ping; Sun, Ya-Li; Ding, Lin; Cai, Fu-Long; Sein, Kyaing
通讯作者	Li, JX (通讯作者)
发表日期	2020
ISSN	1437-3254
EISSN	1437-3262
起始页码	649
结束页码	668
卷号	109 期号:2
英文摘要	Cretaceous mafic-felsic intrusions are extensively distributed in the West Burma terrane (Myanmar), but their petrogenesis and tectonic setting still remain unclear. In this study, whole-rock geochemical and Sr-Nd as well as zircon U-Pb and Hf isotopic data for the Cretaceous mafic-felsic intrusions from the Banmauk-Kawlin area (northern Myanmar) are presented. Precise zircon U-Pb dating results indicate that they emplaced at Cretaceous ( 110-90 Ma) and likely belong to an eastward extension of the coeval Gangdese magmatic belt in the southern Lhasa terrane (Tibet). The studied Cretaceous intrusions (SiO2 = 41.97 to 74.54 wt%) mostly have calc-alkaline and Na-rich characteristics, and strong enrichments in large ion lithophile elements (e.g., Cs, Rb, and K), depletions in Nb and Ta on primitive mantle-normalized diagrams, consistent with geochemical characteristics of arc-type magmas. Most of Cretaceous gabbroic and dioritic intrusions with relatively depleted mantle Sr-Nd-Hf isotopic compositions (Sr-87/Sr-86(i) = 0.7041-0.7048, epsilon Nd(t) = 0.2-6.8, and epsilon Hf(t) = 4.3-15.1) and high Ba/La ratios were possibly derived from partial melting of mantle wedge metasomatized by slab-derived fluids and underwent a certain degree of fractional crystallization. Whereas Cretaceous granodiorite and granite probably formed by partial melting of juvenile arc lower crust on the basis of positive epsilon Nd(t)-epsilon Hf(t) values (- 2.4 to 6.6 and - 2.8 to 15.3) and low initial Sr isotopic ratios (Sr-87/Sr-86(i) = 0.7045-0.7063). A wide range of Th/Nb ratios and Sr-Nd-Hf isotopic values in these intrusions suggests that their juvenile arc lower crust possibly formed by melting of slab-derived fluids and/or sediment melts metasomatized mantle. Overall, Cretaceous ( 110-90 Ma) mafic-felsic intrusions in the West Burma terrane may have formed in an arc setting during subduction of the Neo-Tethyan oceanic lithosphere, suggesting a prolonged Neo-Tethyan magmatic arc system from southern Tibet to Southeast Asia.
关键词	ZIRCON U-PB JURASSIC VOLCANIC-ROCKS A-TYPE GRANITES TECTONIC EVOLUTION SOUTHERN TIBET LU-HF YEBA FORMATION CALC-ALKALINE CONSTRAINTS GANGDESE
英文关键词	Cretaceous; Neo-Tethyan magmatic arc; Mafic-felsic intrusions; Banmauk-Kawlin area; Myanmar
语种	英语
WOS研究方向	Geology
WOS类目	Geosciences, Multidisciplinary
WOS记录号	WOS:000511060300001
来源期刊	INTERNATIONAL JOURNAL OF EARTH SCIENCES
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/259853
推荐引用方式 GB/T 7714	Li, Jin-Xiang,Fan, Wei-Ming,Zhang, Li-Yun,et al. Prolonged Neo-Tethyan magmatic arc in Myanmar: evidence from geochemistry and Sr-Nd-Hf isotopes of Cretaceous mafic-felsic intrusions in the Banmauk-Kawlin area[J]. 中国科学院青藏高原研究所,2020,109(2).
APA	Li, Jin-Xiang.,Fan, Wei-Ming.,Zhang, Li-Yun.,Peng, Tou-Ping.,Sun, Ya-Li.,...&Sein, Kyaing.(2020).Prolonged Neo-Tethyan magmatic arc in Myanmar: evidence from geochemistry and Sr-Nd-Hf isotopes of Cretaceous mafic-felsic intrusions in the Banmauk-Kawlin area.INTERNATIONAL JOURNAL OF EARTH SCIENCES,109(2).
MLA	Li, Jin-Xiang,et al."Prolonged Neo-Tethyan magmatic arc in Myanmar: evidence from geochemistry and Sr-Nd-Hf isotopes of Cretaceous mafic-felsic intrusions in the Banmauk-Kawlin area".INTERNATIONAL JOURNAL OF EARTH SCIENCES 109.2(2020).