Deciphering a multi-event in a non-complex set of detrital zircon U-Pb ages from Carboniferous graywackes of SW Iberia
Autor(a) principal: | |
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Data de Publicação: | 2014 |
Outros Autores: | , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10400.9/2757 |
Resumo: | The determination of U–Pb ages from detrital zircons of sedimentary rocks using LA-ICP-MS has been widely used for the purpose of provenance analysis. One problem that frequently arises is finding a population that appears to be non-complex despite several perceptible age peaks in its spectrum. These peaks are qualitatively defined by means of relative probability diagrams, or PDFs, but it is difficult to quantify their statistical significance relative to a zircon forming multi-event. Thus, can a multi-event in a non-complex set of detrital zircon U–Pb ages be deciphered and characterized? The aim of this study is to attempt to provide an answer to this question by means of statistical analysis. Its objectives are: a) to determine the best minimum number of zircon age populations (peaks), BmPs, b) for the characterization of each peak in terms of age and event duration; c) to compare the results obtained from two datasets showing similar zircon ages; and d) to demonstrate the usefulness of deciphering these BmPs. First, cluster analysis is carried out, aimed at grouping zircon ages into a set of consistent clusters. A Gaussian Kernel function is then fitted to each cluster and summed to obtain a theoretical PDFm (modeled probability density function). Finally, the selected modeled PDFm (that built on the BmPs) is that which reports the lowest number of peaks for which the difference as compared with the original gPDF (global probability density function) is equal to or below 5%. Deciphered BmP peaks can be characterized and used for characterizing and providing an understanding of related event(s). A geological interpretation, based on the results obtained, is attempted. This includes a robust measure for maximum age of deposition for both Cabrela and Mértola graywackes. |
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Deciphering a multi-event in a non-complex set of detrital zircon U-Pb ages from Carboniferous graywackes of SW IberiaGeocronologiaGrauvaquesCarbónicoPenínsula Ibérica (Sudoeste)The determination of U–Pb ages from detrital zircons of sedimentary rocks using LA-ICP-MS has been widely used for the purpose of provenance analysis. One problem that frequently arises is finding a population that appears to be non-complex despite several perceptible age peaks in its spectrum. These peaks are qualitatively defined by means of relative probability diagrams, or PDFs, but it is difficult to quantify their statistical significance relative to a zircon forming multi-event. Thus, can a multi-event in a non-complex set of detrital zircon U–Pb ages be deciphered and characterized? The aim of this study is to attempt to provide an answer to this question by means of statistical analysis. Its objectives are: a) to determine the best minimum number of zircon age populations (peaks), BmPs, b) for the characterization of each peak in terms of age and event duration; c) to compare the results obtained from two datasets showing similar zircon ages; and d) to demonstrate the usefulness of deciphering these BmPs. First, cluster analysis is carried out, aimed at grouping zircon ages into a set of consistent clusters. A Gaussian Kernel function is then fitted to each cluster and summed to obtain a theoretical PDFm (modeled probability density function). Finally, the selected modeled PDFm (that built on the BmPs) is that which reports the lowest number of peaks for which the difference as compared with the original gPDF (global probability density function) is equal to or below 5%. Deciphered BmP peaks can be characterized and used for characterizing and providing an understanding of related event(s). A geological interpretation, based on the results obtained, is attempted. This includes a robust measure for maximum age of deposition for both Cabrela and Mértola graywackes.Repositório do LNEGFerreira, A.Lopes, C.Chichorro, MartimPereira, M. FranciscoSolá, A. Rita2015-05-14T15:41:49Z2014-062014-06-01T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleapplication/pdfhttp://hdl.handle.net/10400.9/2757engFerreira, A... [et al.] - Deciphering a multi-event in a non-complex set of detrital zircon U-Pb ages from Carboniferous graywackes of SW Iberia. In: Chemical Geology, Vol. 378-379 (15 June 2014), p. 62-740009-2541http://dx.doi.org/10.1016/j.chemgeo.2014.04.011info:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2023-08-13T06:26:47ZPortal AgregadorONG |
dc.title.none.fl_str_mv |
Deciphering a multi-event in a non-complex set of detrital zircon U-Pb ages from Carboniferous graywackes of SW Iberia |
title |
Deciphering a multi-event in a non-complex set of detrital zircon U-Pb ages from Carboniferous graywackes of SW Iberia |
spellingShingle |
Deciphering a multi-event in a non-complex set of detrital zircon U-Pb ages from Carboniferous graywackes of SW Iberia Ferreira, A. Geocronologia Grauvaques Carbónico Península Ibérica (Sudoeste) |
title_short |
Deciphering a multi-event in a non-complex set of detrital zircon U-Pb ages from Carboniferous graywackes of SW Iberia |
title_full |
Deciphering a multi-event in a non-complex set of detrital zircon U-Pb ages from Carboniferous graywackes of SW Iberia |
title_fullStr |
Deciphering a multi-event in a non-complex set of detrital zircon U-Pb ages from Carboniferous graywackes of SW Iberia |
title_full_unstemmed |
Deciphering a multi-event in a non-complex set of detrital zircon U-Pb ages from Carboniferous graywackes of SW Iberia |
title_sort |
Deciphering a multi-event in a non-complex set of detrital zircon U-Pb ages from Carboniferous graywackes of SW Iberia |
author |
Ferreira, A. |
author_facet |
Ferreira, A. Lopes, C. Chichorro, Martim Pereira, M. Francisco Solá, A. Rita |
author_role |
author |
author2 |
Lopes, C. Chichorro, Martim Pereira, M. Francisco Solá, A. Rita |
author2_role |
author author author author |
dc.contributor.none.fl_str_mv |
Repositório do LNEG |
dc.contributor.author.fl_str_mv |
Ferreira, A. Lopes, C. Chichorro, Martim Pereira, M. Francisco Solá, A. Rita |
dc.subject.por.fl_str_mv |
Geocronologia Grauvaques Carbónico Península Ibérica (Sudoeste) |
topic |
Geocronologia Grauvaques Carbónico Península Ibérica (Sudoeste) |
description |
The determination of U–Pb ages from detrital zircons of sedimentary rocks using LA-ICP-MS has been widely used for the purpose of provenance analysis. One problem that frequently arises is finding a population that appears to be non-complex despite several perceptible age peaks in its spectrum. These peaks are qualitatively defined by means of relative probability diagrams, or PDFs, but it is difficult to quantify their statistical significance relative to a zircon forming multi-event. Thus, can a multi-event in a non-complex set of detrital zircon U–Pb ages be deciphered and characterized? The aim of this study is to attempt to provide an answer to this question by means of statistical analysis. Its objectives are: a) to determine the best minimum number of zircon age populations (peaks), BmPs, b) for the characterization of each peak in terms of age and event duration; c) to compare the results obtained from two datasets showing similar zircon ages; and d) to demonstrate the usefulness of deciphering these BmPs. First, cluster analysis is carried out, aimed at grouping zircon ages into a set of consistent clusters. A Gaussian Kernel function is then fitted to each cluster and summed to obtain a theoretical PDFm (modeled probability density function). Finally, the selected modeled PDFm (that built on the BmPs) is that which reports the lowest number of peaks for which the difference as compared with the original gPDF (global probability density function) is equal to or below 5%. Deciphered BmP peaks can be characterized and used for characterizing and providing an understanding of related event(s). A geological interpretation, based on the results obtained, is attempted. This includes a robust measure for maximum age of deposition for both Cabrela and Mértola graywackes. |
publishDate |
2014 |
dc.date.none.fl_str_mv |
2014-06 2014-06-01T00:00:00Z 2015-05-14T15:41:49Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10400.9/2757 |
url |
http://hdl.handle.net/10400.9/2757 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
Ferreira, A... [et al.] - Deciphering a multi-event in a non-complex set of detrital zircon U-Pb ages from Carboniferous graywackes of SW Iberia. In: Chemical Geology, Vol. 378-379 (15 June 2014), p. 62-74 0009-2541 http://dx.doi.org/10.1016/j.chemgeo.2014.04.011 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.source.none.fl_str_mv |
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Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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RCAAP |
institution |
RCAAP |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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