气候变化领域集成服务门户(CCPortal): Geochemical discrimination of the altered volcanic tuff from sediments in the Lunpola Basin, central Tibetan Plateau

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DOI	10.1180/clm.2020.39
	Geochemical discrimination of the altered volcanic tuff from sediments in the Lunpola Basin, central Tibetan Plateau
	Mao, Ziqiang; Fang, Xiaomin; Yang, Yibo; Ye, Chengcheng; Zhang, Tao; Zhang, Weilin; Zan, Jinbo
通讯作者	Fang, XM (通讯作者)
发表日期	2020
ISSN	0009-8558
EISSN	1471-8030
起始页码	303
结束页码	319
卷号	55 期号:4
英文摘要	Volcanic tuffs are important in determining the stratigraphic age of sedimentary sequences, which is closely related to the tectonic, sedimentological, geomorphological, palaeoclimatic, and palaeo-ecological evolution of the sequences. However, it may be difficult practically to identify tuffs in stratigraphic sections, especially when they are altered after deposition. In this study, a series of petrographic, mineralogical, and geochemical analyses was deployed in the tuff layers cropping out in the Lunpola Basin of the central Tibetan Plateau, which is a crucial site for studying the dynamics and processes of the Cenozoic uplift of the Tibetan Plateau and its environmental impacts. In these pyroclastic layers, authigenic analcime is the main volcanic glass alteration product. The analcime-bearing samples are Na-enriched, in contrast to the K-abundant magmatic rocks in the central Tibetan Plateau. The distribution patterns of the rare earth elements (REEs) of the bulk analcime-bearing samples are similar to those of the magmatic rocks but different from those of the analcime-poor sediments and analogues of well-mixed upper continental material (e.g. the upper continental crust and post-Archaean Australian average shales). The distinct distributions of Na and REEs among analcime-bearing samples, analcime-poor sediments, and volcanic rocks reveal that analcime formed both from alteration of volcanic material and from mixing processes with non-volcanic sediments. It is proposed, therefore, that the discrimination plot of Na2O/Al2O3-(La/Yb)(N) may be used to distinguish the analcime-related pyroclastic rocks from the basin sedimentary sequence, and thus it may provide a means of discriminating between various volcanic material and of supporting age dating by tephrochronology in the central Tibetan Plateau.
关键词	EAST-WEST EXTENSION EARLY MIOCENE BIRTH ASIA SUTURE ZONE HOH XIL BASIN ULTRAPOTASSIC MAGMATISM CONTINENTAL COLLISION MODERATE ELEVATION SOUTHERN TIBET NORTHERN TIBET MANTLE SOURCE
英文关键词	altered tuff; analcime; La/Yb ratio; Na/Al ratio; pyroclastic; rare earth element
语种	英语
WOS研究方向	Chemistry ; Geology ; Mineralogy
WOS类目	Chemistry, Physical ; Geosciences, Multidisciplinary ; Mineralogy
WOS记录号	WOS:000634389500004
来源期刊	CLAY MINERALS
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/259727
推荐引用方式 GB/T 7714	Mao, Ziqiang,Fang, Xiaomin,Yang, Yibo,et al. Geochemical discrimination of the altered volcanic tuff from sediments in the Lunpola Basin, central Tibetan Plateau[J]. 中国科学院青藏高原研究所,2020,55(4).
APA	Mao, Ziqiang.,Fang, Xiaomin.,Yang, Yibo.,Ye, Chengcheng.,Zhang, Tao.,...&Zan, Jinbo.(2020).Geochemical discrimination of the altered volcanic tuff from sediments in the Lunpola Basin, central Tibetan Plateau.CLAY MINERALS,55(4).
MLA	Mao, Ziqiang,et al."Geochemical discrimination of the altered volcanic tuff from sediments in the Lunpola Basin, central Tibetan Plateau".CLAY MINERALS 55.4(2020).