Ar-40/Ar-39 ages and stable isotopes of supergene jarosite from the Baiyin VHMS ore field, NE Tibetan Plateau with paleoclimatic implications

doi:10.1007/s11434-014-0276-8

	Ar-40/Ar-39 ages and stable isotopes of supergene jarosite from the Baiyin VHMS ore field, NE Tibetan Plateau with paleoclimatic implications
	Chen, Lei 1,2; Li, Jianwei 2,3
刊名	CHINESE SCIENCE BULLETIN
	2014-08-01
卷号	59 期号:24 页码:2999-3009
关键词	Jarosite Ar-40/Ar-39 geochronology Stable isotopes Qilian Mountain Paleoclimate
ISSN号	1001-6538
DOI	10.1007/s11434-014-0276-8
文献子类	Article
英文摘要	Supergene jarosite is widely distributed in weathering profiles derived from hypogene sulfide ores. Precise Ar-40/Ar-39 dating and determination of hydrogen and oxygen isotopes of supergene jarosite can not only place tight constraints on the timing and history of continental weathering and supergene enrichment of sulfide ore deposits, but also shed significant insights into paleoclimatic conditions and tectonic uplift responsible for the weathering. In this paper, we present a preliminary study of Ar-40/Ar-39 geochronology and stable isotope geochemistry of supergene jarosite from the early Paleozoic Zheyaoshan volcanic-hosted massive sulfide deposit of the Baiyin ore field located in the eastern portion of the Qilian Mountain along the northeastern (NE) margin of the Tibetan Plateau in an attempt to better understand the climatic conditions prevailed during the pervasive weathering in the region. Jarosite from the Zheyaoshan mining area occurs either as gravels within alluvial deposits over low-relief flat-top hills or cm-wide veins crosscutting weathered sulfide ores or their wall rocks. The gravels consist of massive jarosite aggregates with tabular crystal morphology and contain 8.21 wt%-8.31 wt% K2O on average. Two jarosite grains extracted from the gravels (08-02-2 and 08-02-5) yield well-defined Ar-40/Ar-39 plateau ages of 37.1 +/- A 0.3 and 41.2 +/- A 0.4 Ma (2 sigma), respectively. They have delta D values of -133 aEuro degrees and -156 aEuro degrees, and values of 2.6 aEuro degrees and 2.5 aEuro degrees. The vein-type jarosite consists of hexagonal pyramid crystals and contains much lower K2O, averaging at 2.44 wt%-2.72 wt%. Two jarosite veins (06-16-3 and 06-16-4) yield similar plateau ages of 3.2 +/- A 0.1 and 3.3 +/- A 0.1 Ma (2 sigma), respectively. These jarosite veins have delta D values of -158 aEuro degrees and -160 aEuro degrees, and values of 2.8 aEuro degrees and 2.5 aEuro degrees. The Ar-40/Ar-39 ages indicate that sulfide ores of the Zheyaoshan deposit must have been brought to the surface since the late Eocene, and subsequently subjected to prolonged oxidation and supergene enrichment. The precipitation and preservation of jarosite in weathering profiles indicate that arid-semiarid climatic conditions must have been prevailed since the late Eocene. The hydrogen and oxygen isotopes of the jarosite further point to variation of climatic conditions in the area, with the Pliocene being slightly cooler relative to the late Eocene. Given that weathering profiles overlying sulfide ore deposits are widely distributed along the Qilian Mountain, systematic studies of Ar-40/Ar-39 geochronology and stable isotope geochemistry of jarosite-group minerals from these profiles would provide valuable information on the timing and evolution of regional tectonic uplift, paleoclimatic changes, and supergene mineralization in this mountainous belt along the NE edge of the Tibetan Plateau.
WOS关键词	ATACAMA-DESERT ; NORTHERN CHILE ; K-AR ; GEOCHRONOLOGY ; ALUNITE ; EVOLUTION ; GEOCHEMISTRY ; AUSTRALIA ; HISTORY ; UPLIFT
WOS研究方向	Science & Technology - Other Topics
语种	英语
出版者	SCIENCE PRESS
WOS记录号	WOS:000339104800010
资助机构	National Natural Science Foundation of China(41325007 ; National Natural Science Foundation of China(41325007 ; National Natural Science Foundation of China(41325007 ; National Natural Science Foundation of China(41325007 ; Program for New Century Excellent Talents in University(NCET-05-0665) ; Program for New Century Excellent Talents in University(NCET-05-0665) ; Program for New Century Excellent Talents in University(NCET-05-0665) ; Program for New Century Excellent Talents in University(NCET-05-0665) ; 40573021) ; 40573021) ; 40573021) ; 40573021) ; National Natural Science Foundation of China(41325007 ; National Natural Science Foundation of China(41325007 ; National Natural Science Foundation of China(41325007 ; National Natural Science Foundation of China(41325007 ; Program for New Century Excellent Talents in University(NCET-05-0665) ; Program for New Century Excellent Talents in University(NCET-05-0665) ; Program for New Century Excellent Talents in University(NCET-05-0665) ; Program for New Century Excellent Talents in University(NCET-05-0665) ; 40573021) ; 40573021) ; 40573021) ; 40573021) ; National Natural Science Foundation of China(41325007 ; National Natural Science Foundation of China(41325007 ; National Natural Science Foundation of China(41325007 ; National Natural Science Foundation of China(41325007 ; Program for New Century Excellent Talents in University(NCET-05-0665) ; Program for New Century Excellent Talents in University(NCET-05-0665) ; Program for New Century Excellent Talents in University(NCET-05-0665) ; Program for New Century Excellent Talents in University(NCET-05-0665) ; 40573021) ; 40573021) ; 40573021) ; 40573021) ; National Natural Science Foundation of China(41325007 ; National Natural Science Foundation of China(41325007 ; National Natural Science Foundation of China(41325007 ; National Natural Science Foundation of China(41325007 ; Program for New Century Excellent Talents in University(NCET-05-0665) ; Program for New Century Excellent Talents in University(NCET-05-0665) ; Program for New Century Excellent Talents in University(NCET-05-0665) ; Program for New Century Excellent Talents in University(NCET-05-0665) ; 40573021) ; 40573021) ; 40573021) ; 40573021)
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/85848]
专题	中国科学院地质与地球物理研究所
通讯作者	Li, Jianwei
作者单位	1.Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, Beijing 100029, Peoples R China 2.China Univ Geosci, State Key Lab Geol Proc & Mineral Resources, Wuhan 430074, Peoples R China 3.China Univ Geosci, Fac Earth Resources, Wuhan 430074, Peoples R China
推荐引用方式 GB/T 7714	Chen, Lei,Li, Jianwei. Ar-40/Ar-39 ages and stable isotopes of supergene jarosite from the Baiyin VHMS ore field, NE Tibetan Plateau with paleoclimatic implications[J]. CHINESE SCIENCE BULLETIN,2014,59(24):2999-3009.
APA	Chen, Lei,&Li, Jianwei.(2014).Ar-40/Ar-39 ages and stable isotopes of supergene jarosite from the Baiyin VHMS ore field, NE Tibetan Plateau with paleoclimatic implications.CHINESE SCIENCE BULLETIN,59(24),2999-3009.
MLA	Chen, Lei,et al."Ar-40/Ar-39 ages and stable isotopes of supergene jarosite from the Baiyin VHMS ore field, NE Tibetan Plateau with paleoclimatic implications".CHINESE SCIENCE BULLETIN 59.24(2014):2999-3009.