Genesis and open-system evolution of Quaternary magmas beneath   southeastern margin of Tibet: Constraints from Sr-Nd-Pb-Hf isotope   systematics

doi:10.1016/j.lithos.2016.12.012

CORC > 北京大学 > 地球与空间科学学院

	Genesis and open-system evolution of Quaternary magmas beneath southeastern margin of Tibet: Constraints from Sr-Nd-Pb-Hf isotope systematics
	Zou, Haibo ; Ma, Mingjia ; Fan, Qicheng ; Xu, Bei ; Li, Shuang-Qing ; Zhao, Yongwei ; King, David T., Jr.
刊名	LITHOS
	2017
关键词	Quaternary volcano Assimilation fractional crystallization Tengchong Continental subduction indo-Asian collision TENGCHONG VOLCANIC FIELD INDO-ASIAN COLLISION ZIRCON U-PB TRACE-ELEMENT MANTLE SOURCE CRUSTAL STRUCTURE WESTERN YUNNAN ULTRAPOTASSIC MAGMATISM PLATEAU IMPLICATIONS SOUTHWESTERN CHINA
DOI	10.1016/j.lithos.2016.12.012
英文摘要	Post-collisional volcanic rocks on the Tibetan Plateau and its margins contain valuable information about the geodynamic processes associated with this Cenozoic continent-continent collision. The Quaternary Tengchong volcanic field at the southeastern margin of the Tibetan Plateau formed high-potassium calc-alkaline volcanic rocks. Herein, we present comprehensive Nd-Sr-Pb-Hf isotopic and elemental data for trachybasalts, basaltic trachyandesites, and trachyandesites from four Quaternary Tengchong volcanoes (Maanshan, Dayingshan, Heikongshan, and Laoguipo) in order to understand their magma genesis and evolution as well as tectonic significance. Good correlations between SiO2 content and the ratios Sr-87/Sr-86, Nd-143/Nd-144. (206)pb/(204)pb, and Hf-177/Hf-176 for these Quaternary volcanics strongly suggest that the combined assimilation and fractional crystallization (AFC) was an important process in the origin of basaltic trachyandesites and trachyandesites. High Y and Yb contents and low Sr/Y ratios of these basaltic trachyandesites and trachyandesites are uncharacteristic of adakites that formed by partial melting of eclogitic lower crust or partial melting of basaltic oceanic crust with eclogite as a restite. A combined assimilation-fractional crystallization model is proposed for these basaltic trachyandesites and trachyandesites. Nd-Sr-Pb-Hf isotopes for the uncontaminated Tengchong magma (trachybasalts with SiO2 < 52.5 wt.% and MgO > 5.5% wt.%) reflect a heterogeneous enriched mantle source. High Th/U, Th/Ta, and Rb/Nb ratios and Nd-Sr-Pb-Hf isotope characteristics of the uncontaminated magmas suggest that the enriched mantle beneath Tengchong formed as a result of subduction of clay-rich sediments, which probably came from the Indian continental plate. Partial melting of the enriched mantle was generated by deep continental subduction coupled with recent regional extension in the Tengchong area. (C) 2016 Elsevier B.V. All rights reserved.; NSF of China [41272070]; SCI(E); ARTICLE; 278-290; 272
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/475498]
专题	地球与空间科学学院
推荐引用方式 GB/T 7714	Zou, Haibo,Ma, Mingjia,Fan, Qicheng,et al. Genesis and open-system evolution of Quaternary magmas beneath southeastern margin of Tibet: Constraints from Sr-Nd-Pb-Hf isotope systematics[J]. LITHOS,2017.
APA	Zou, Haibo.,Ma, Mingjia.,Fan, Qicheng.,Xu, Bei.,Li, Shuang-Qing.,...&King, David T., Jr..(2017).Genesis and open-system evolution of Quaternary magmas beneath southeastern margin of Tibet: Constraints from Sr-Nd-Pb-Hf isotope systematics.LITHOS.
MLA	Zou, Haibo,et al."Genesis and open-system evolution of Quaternary magmas beneath southeastern margin of Tibet: Constraints from Sr-Nd-Pb-Hf isotope systematics".LITHOS (2017).