Characteristics of deep sources and tectonic-magmatic evolution of the early Cretaceous volcanics in Genhe area, Da-Hinggan Mountains: Constraints of Sr-Nd-Pb-Hf isotopic geochemistries

	Characteristics of deep sources and tectonic-magmatic evolution of the early Cretaceous volcanics in Genhe area, Da-Hinggan Mountains: Constraints of Sr-Nd-Pb-Hf isotopic geochemistries
	Zhang LianChang 1; Chen ZhiGuang 1; Zhou Xinhua 2; Ying JiFeng 2; Wang Fei 2; Mang YuTao 2
刊名	ACTA PETROLOGICA SINICA
	2007-11-01
卷号	23 期号:11 页码:2823-2835
关键词	late mesozoic volcanies characteristics of deep sources tectonic-magmatic evolution isotopic geochemistry da-hinggan mountains
ISSN号	1000-0569
文献子类	Article
英文摘要	Late Mesozoic volcanic rocks section in Genhe area, northeast of Inner-Mongolia, is the important part of Da-Hinggan Mountains Mesozoic volcanic rocks. They are mainly composed of trachy-basalt, basaltic trachy-andesite, trachy-andesite, trachyte and rhyolite. Through geochronological study, including Ar-40-Ar-39 and SHRIMP zircon U-Pb dating, our study group attained ages of Genhe volcanic section, which have the range from 115Ma to 140Ma. This result indicates that these volcanic rocks were formed in three gyrations of volcanic explosion in early Cretaceous. The major elements of the samples show that geochemical characteristics of rocks in the lower and upper volcanic section are similar. Both of them have higher Al2O3, K2O and total alkaline contents, and relatively high in MgO and Mg-#. The trace elements demonstrate total LREE enrichment with insignificant Eu anomalies (delta Eu = 0.83-1. 00) and intense fractionation between LREE and HREE. The primitive mantle-normalized spidergrams are characterized by LILE enrichment and HFSE depletion, especially for a significantly negative Nb-Ta anomaly. Isotopic geochemistries show that values of epsilon(Nd) (t) range from 1.5 to 3.6, and ( Sr-87/(86) Sr)(i) from 0.704571 to 0.705907. The geochemical characteristics of trachytes, in middle volcanic section, are similar with basic and intermediate-basic volcanics of lower and upper volcanic section. However, MgO content and Mg-# is lower, and Ti shows intense depletion. Rhyolites of middle rocks section have higher SiO2 and more lower MgO and Mg-# values. Trace elements show the characteristics of significant Eu anomalies ( delta Eu = 0. 16 - 0. 85), intense depletion of Sr and Ba, and high (Sr-87/(86) Sr)(i) values. According to geochemistries of basic and intermediate-basic volcanics, it is inferred that these rocks formed in an intracontinental extension setting. On the other hand, some characteristics of are volcanics can be recognised in these rocks, which probably relate with dynamics and geochemical processes of subduction among plates in ancient Asian ocean territory. The origination of volcanic magma is speculated from a metasomatized mantle wedge, which had been modified by paleozoic subducted ocean slab. Fractional crystallization is the most important evolutionary type during magma evolvement. The early Cretaceous volcanics of Genhe area were formed in the transition stage from ancient Asia to paleo-pacific structural domain, which were caused by coupling effect of postorogenic extension Mongol-Okhotsk zone and subduction of west Pacific slab.
WOS关键词	EXTENSION ; MONGOLIA ; CHINA ; ARC ; GEOCHRONOLOGY ; ROCKS
WOS研究方向	Geology
语种	英语
出版者	SCIENCE CHINA PRESS
WOS记录号	WOS:000254139500013
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/68166]
专题	中国科学院地质与地球物理研究所
通讯作者	Zhang LianChang
作者单位	1.Chinese Acad Sci, Inst Geol & Geophys, Key Lab Mineral Resources, Beijing 100029, Peoples R China 2.Chinese Acad Sci, Inst Geol & Geophys, Beijing 100029, Peoples R China
推荐引用方式 GB/T 7714	Zhang LianChang,Chen ZhiGuang,Zhou Xinhua,et al. Characteristics of deep sources and tectonic-magmatic evolution of the early Cretaceous volcanics in Genhe area, Da-Hinggan Mountains: Constraints of Sr-Nd-Pb-Hf isotopic geochemistries[J]. ACTA PETROLOGICA SINICA,2007,23(11):2823-2835.
APA	Zhang LianChang,Chen ZhiGuang,Zhou Xinhua,Ying JiFeng,Wang Fei,&Mang YuTao.(2007).Characteristics of deep sources and tectonic-magmatic evolution of the early Cretaceous volcanics in Genhe area, Da-Hinggan Mountains: Constraints of Sr-Nd-Pb-Hf isotopic geochemistries.ACTA PETROLOGICA SINICA,23(11),2823-2835.
MLA	Zhang LianChang,et al."Characteristics of deep sources and tectonic-magmatic evolution of the early Cretaceous volcanics in Genhe area, Da-Hinggan Mountains: Constraints of Sr-Nd-Pb-Hf isotopic geochemistries".ACTA PETROLOGICA SINICA 23.11(2007):2823-2835.