Screening criteria for reliable U-Pb geochronology and oxygen isotope analysis in uranium-rich zircons: A case study from the Suzhou A-type granites, SE China

doi:10.1016/j.lithos.2014.02.002

	Screening criteria for reliable U-Pb geochronology and oxygen isotope analysis in uranium-rich zircons: A case study from the Suzhou A-type granites, SE China
	Gao, Yu-Ya 1,2,3; Li, Xian-Hua 1; Griffin, William L.3; O'Reilly, Suzanne Y.3; Wang, Ya-Fei 1,2
刊名	LITHOS
	2014-04-01
卷号	192 页码:180-191
关键词	Southeastern China Low-delta O-18 granite Zircon radiation damage Zircon metamictization Zircon and quartz oxygen isotope analyses Zircon U-Pb dating
ISSN号	0024-4937
DOI	10.1016/j.lithos.2014.02.002
文献子类	Article
英文摘要	Zircon is widely used in geochronology and as an isotopic tracer in igneous processes. However, the use of isotopic data obtained from zircon requires evaluating of processes that might compromise the robustness of its isotopic systems. In this study we have assessed how different U contents and degrees of metamictization have affected the SIMS U-Pb and oxygen-isotope signatures of zircon-quartz pairs from the U-rich A-type granites from Suzhou (southern China). Our SIMS results show that zircons with low U concentrations define a U-Pb age of 126.1 +/- 0.5 Ma and homogeneous mantle 8180 values of 5.34 +/- 0.46%. (2SD). In contrast, zircons with high U contents show a positive correlation between U concentration and U-Pb ages (123-157 Ma) and a negative correlation between U concentration and 8180 values (range from 5.3 to 3.7%.). These observations are integrated with Raman spectra and oxygen-isotope analyses of coexisting quartz to reveal that the anomalously high U-Pb ages and low 6180 values reflect the degree of radiation damage to the zircons (quantified by radiation dose in displacements-per-atom, D-dpa). The older SIMS U-Pb ages are a direct result of the matrix effect caused by metamictization, whereas the low 8180 values result from interaction with OH-bearing fluids, the infiltration and diffusion of which was facilitated in the radiation-damaged areas. Coexisting quartz preserves primary O-isotope signatures of the magma better than high-U zircon, and thus provides a constraint for zircon oxygen-isotope values. This study demonstrates that it is essential to evaluate the degree of radiation damage before/after carrying out dating or oxygen-isotope analysis on zircons with high U contents. The results indicate that for the Suzhou pluton, D-dpa < 0.03 is a robust discriminant threshold to identify zircons with primary oxygen-isotope ratios, and D-dpa < 0.08 is a robust discriminant to screen for reliable U-Pb dating. These different screening values reflect the evidence that oxygen-isotope compositions can be affected at a lower level of post-crystallization disturbance of the zircon lattice than the U-Pb system. (C) 2014 Elsevier B.V. All rights reserved.
WOS关键词	RADIOACTIVITY-INDUCED DAMAGE ; NATURAL REFERENCE MATERIAL ; RADIATION-DAMAGE ; ION MICROPROBE ; EASTERN CHINA ; TH-PB ; WORKING REFERENCE ; DETRITAL ZIRCON ; MAGMATIC ZIRCON ; TRACE-ELEMENT
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000335102100012
资助机构	National Natural Science Foundation of China(41173010) ; National Natural Science Foundation of China(41173010) ; National Natural Science Foundation of China(41173010) ; National Natural Science Foundation of China(41173010) ; Ministry of Science and Technology(2012CB416702) ; Ministry of Science and Technology(2012CB416702) ; Ministry of Science and Technology(2012CB416702) ; Ministry of Science and Technology(2012CB416702) ; Macquarie University Interantional Postgraduate Scholarship ; Macquarie University Interantional Postgraduate Scholarship ; Macquarie University Interantional Postgraduate Scholarship ; Macquarie University Interantional Postgraduate Scholarship ; National Natural Science Foundation of China(41173010) ; National Natural Science Foundation of China(41173010) ; National Natural Science Foundation of China(41173010) ; National Natural Science Foundation of China(41173010) ; Ministry of Science and Technology(2012CB416702) ; Ministry of Science and Technology(2012CB416702) ; Ministry of Science and Technology(2012CB416702) ; Ministry of Science and Technology(2012CB416702) ; Macquarie University Interantional Postgraduate Scholarship ; Macquarie University Interantional Postgraduate Scholarship ; Macquarie University Interantional Postgraduate Scholarship ; Macquarie University Interantional Postgraduate Scholarship ; National Natural Science Foundation of China(41173010) ; National Natural Science Foundation of China(41173010) ; National Natural Science Foundation of China(41173010) ; National Natural Science Foundation of China(41173010) ; Ministry of Science and Technology(2012CB416702) ; Ministry of Science and Technology(2012CB416702) ; Ministry of Science and Technology(2012CB416702) ; Ministry of Science and Technology(2012CB416702) ; Macquarie University Interantional Postgraduate Scholarship ; Macquarie University Interantional Postgraduate Scholarship ; Macquarie University Interantional Postgraduate Scholarship ; Macquarie University Interantional Postgraduate Scholarship ; National Natural Science Foundation of China(41173010) ; National Natural Science Foundation of China(41173010) ; National Natural Science Foundation of China(41173010) ; National Natural Science Foundation of China(41173010) ; Ministry of Science and Technology(2012CB416702) ; Ministry of Science and Technology(2012CB416702) ; Ministry of Science and Technology(2012CB416702) ; Ministry of Science and Technology(2012CB416702) ; Macquarie University Interantional Postgraduate Scholarship ; Macquarie University Interantional Postgraduate Scholarship ; Macquarie University Interantional Postgraduate Scholarship ; Macquarie University Interantional Postgraduate Scholarship
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/85136]
专题	中国科学院地质与地球物理研究所
通讯作者	Li, Xian-Hua
作者单位	1.Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, Beijing 100029, Peoples R China 2.Univ Chinese Acad Sci, Coll Earth Sci, Beijing 100049, Peoples R China 3.Macquarie Univ, Dept Earth & Planetary Sci, Australian Res Council Ctr Excellence Core Crust, Sydney, NSW 2019, Australia
推荐引用方式 GB/T 7714	Gao, Yu-Ya,Li, Xian-Hua,Griffin, William L.,et al. Screening criteria for reliable U-Pb geochronology and oxygen isotope analysis in uranium-rich zircons: A case study from the Suzhou A-type granites, SE China[J]. LITHOS,2014,192:180-191.
APA	Gao, Yu-Ya,Li, Xian-Hua,Griffin, William L.,O'Reilly, Suzanne Y.,&Wang, Ya-Fei.(2014).Screening criteria for reliable U-Pb geochronology and oxygen isotope analysis in uranium-rich zircons: A case study from the Suzhou A-type granites, SE China.LITHOS,192,180-191.
MLA	Gao, Yu-Ya,et al."Screening criteria for reliable U-Pb geochronology and oxygen isotope analysis in uranium-rich zircons: A case study from the Suzhou A-type granites, SE China".LITHOS 192(2014):180-191.