Staff View: U-Pb dating by zircon dissolution method using chemical abrasion

U-Pb dating by zircon dissolution method using chemical abrasion

Chemical abrasion was carried out on zircons grains of the Temora II standard for U-Pb dating prior to analyses using in situ Laser Ablation-MultiCollector Ion Coupled Plasma Mass Spectrometer (LA-ICPMS) followed by the Isotope Dissolution Thermal Ionization Mass Spectrometer (ID-TIMS) method. The p...

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Main Authors:	Takehara, Lucy, Chemale Júnior, Farid, Hartmann, Léo A., Dussin, Ivo A., Kawashita, Koji
Format:	Artigo
Language:	English
Published:	Academia Brasileira de Ciências 2017
Subjects:	chemical abrasion ID-TIMS LA-MC-ICPMS U-Pb dating zircon dissolution abrasão química datação U-Pb dissolução de zircão
Online Access:	http://repositorio.unb.br/handle/10482/28258
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spelling	ir-10482-282582019-03-28T14:02:46Z U-Pb dating by zircon dissolution method using chemical abrasion Takehara, Lucy Chemale Júnior, Farid Hartmann, Léo A. Dussin, Ivo A. Kawashita, Koji chemical abrasion ID-TIMS LA-MC-ICPMS U-Pb dating zircon dissolution abrasão química ID-TIMS LA-MC-ICPMS datação U-Pb dissolução de zircão Chemical abrasion was carried out on zircons grains of the Temora II standard for U-Pb dating prior to analyses using in situ Laser Ablation-MultiCollector Ion Coupled Plasma Mass Spectrometer (LA-ICPMS) followed by the Isotope Dissolution Thermal Ionization Mass Spectrometer (ID-TIMS) method. The proposed methodology was herein applied in order to reduce primarily the effects of secondary Pb loss, the presence of common lead and/or silicate impurities. Nine Temora II zircon grains were analyzed by the laser ablation method yielding an age of 418.3±4.3 Ma. Zircon grains of a same population were separated for chemical abrasion before dissolution and mass spectrometry analyses. Six fractions of them were separated for isotope dissolution using 235U-205Pb mixed spike after we have checked and assured the laboratory conditions of low blank values for total Pb of less than 2 pg/g. The obtained U-Pb zircon age by the ID-TIMS method was 415.7±1.8 Ma (error 0.43 %) based on four successful determinations. The results are consistent with the published ages for the Temora diorite (Temora I â 416.75±1.3 Ma; Temora II â 416.78±0.33 Ma) and established as 416±0.33 Ma. The technique is thus recommended for high precision U-Pb zircon analyses (error < 1 %), mainly for high resolution stratigraphic studies of Phanerozoic sequences. Este trabalho apresenta a técnica de abrasão química em zircões do padrão Temora II aplicada em datação de U-Pb por Dissolução Isotópica e Espectrometria de Massa por Ionização Térmica, método DI-ESIT. O emprego deste método tem como princípio diminuir os efeitos da perda secundária de Pb radiogênico antes da dissolução. Em primeira instância, os zircões foram analisados pelo método in situ com uso de Microssonda Laser acoplada a um Espectrômetro de Massa Multicoletor com Plasma Acoplado Indutivamente (MC-ICP-MS), cujo objetivo foi identificar os grãos de zircão de fase de cristalização simples sem sobrecrescimento. Nove cristais de zircão analisados com microssonda a laser forneceram uma idade 418,3±4,3 Ma. Da mesma população foram separados cristais de zircão para datação utilizando a técnica de abrasão química e posterior análise pelo método DI-ESIT. Seis amostras de zircão foram separadas para diluição isotópica com adição de um traçador isotópico combinado U235-Pb205, em condições laboratoriais de brancos analíticos de Pb total menor que 2 pg/g. A idade U-Pb em zircão obtida foi 415,7±1,8 Ma (erro 0,43 %) com base em cinco amostras de zircão. Os resultados são concordantes com aquelas idades publicadas para o diorito Temora (Temora I â 416,75±1,3 Ma; Temora II â 416,78±0,33 Ma). A técnica descrita aqui é, portanto recomendada para ser aplicada em análises isotópicas de U-Pb com alta precisão (erros menor que 1%) para estudos de estratigrafia de alta resolução de sequências fanerozóicas. 2017-12-07T04:58:02Z 2017-12-07T04:58:02Z 2012 Artigo An. Acad. Bras. Ciênc.,v.84,n.2,p.399-405,2012 0001-3765 http://repositorio.unb.br/handle/10482/28258 10.1590/S0001-37652012000200011 en Acesso Aberto application/pdf Academia Brasileira de Ciências http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652012000200011&lng=en&nrm=iso http://www.scielo.br/scielo.php?script=sci_abstract&pid=S0001-37652012000200011&lng=en&nrm=iso http://www.scielo.br/scielo.php?script=sci_pdf&pid=S0001-37652012000200011&lng=en&nrm=iso
institution	REPOSITORIO UNB
collection	REPOSITORIO UNB
language	English
topic	chemical abrasion ID-TIMS LA-MC-ICPMS U-Pb dating zircon dissolution abrasão química ID-TIMS LA-MC-ICPMS datação U-Pb dissolução de zircão
spellingShingle	chemical abrasion ID-TIMS LA-MC-ICPMS U-Pb dating zircon dissolution abrasão química ID-TIMS LA-MC-ICPMS datação U-Pb dissolução de zircão Takehara, Lucy Chemale Júnior, Farid Hartmann, Léo A. Dussin, Ivo A. Kawashita, Koji U-Pb dating by zircon dissolution method using chemical abrasion
description	Chemical abrasion was carried out on zircons grains of the Temora II standard for U-Pb dating prior to analyses using in situ Laser Ablation-MultiCollector Ion Coupled Plasma Mass Spectrometer (LA-ICPMS) followed by the Isotope Dissolution Thermal Ionization Mass Spectrometer (ID-TIMS) method. The proposed methodology was herein applied in order to reduce primarily the effects of secondary Pb loss, the presence of common lead and/or silicate impurities. Nine Temora II zircon grains were analyzed by the laser ablation method yielding an age of 418.3±4.3 Ma. Zircon grains of a same population were separated for chemical abrasion before dissolution and mass spectrometry analyses. Six fractions of them were separated for isotope dissolution using 235U-205Pb mixed spike after we have checked and assured the laboratory conditions of low blank values for total Pb of less than 2 pg/g. The obtained U-Pb zircon age by the ID-TIMS method was 415.7±1.8 Ma (error 0.43 %) based on four successful determinations. The results are consistent with the published ages for the Temora diorite (Temora I â 416.75±1.3 Ma; Temora II â 416.78±0.33 Ma) and established as 416±0.33 Ma. The technique is thus recommended for high precision U-Pb zircon analyses (error < 1 %), mainly for high resolution stratigraphic studies of Phanerozoic sequences.
format	Artigo
author	Takehara, Lucy Chemale Júnior, Farid Hartmann, Léo A. Dussin, Ivo A. Kawashita, Koji
author_sort	Takehara, Lucy
title	U-Pb dating by zircon dissolution method using chemical abrasion
title_short	U-Pb dating by zircon dissolution method using chemical abrasion
title_full	U-Pb dating by zircon dissolution method using chemical abrasion
title_fullStr	U-Pb dating by zircon dissolution method using chemical abrasion
title_full_unstemmed	U-Pb dating by zircon dissolution method using chemical abrasion
title_sort	u-pb dating by zircon dissolution method using chemical abrasion
publisher	Academia Brasileira de Ciências
publishDate	2017
url	http://repositorio.unb.br/handle/10482/28258
_version_	1641988754836029440
score	13.657419

U-Pb dating by zircon dissolution method using chemical abrasion

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