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STRATI 2013 pp 717-722 | Cite as

Deciphering a Multipeak Event in a Noncomplex Set of Detrital Zircon U–Pb Ages

  • A. FerreiraEmail author
  • C. Lopes
  • M. Chichorro
  • M. F. Pereira
  • A. R. Sola
Conference paper
Part of the Springer Geology book series (SPRINGERGEOL)

Abstract

The determination of U–Pb ages from detrital zircons of sedimentary rocks using LA–ICP–MS has been widely used to develop studies of provenance analysis. A problem that frequently arises is to find a population that appears to be noncomplex despite several perceptible age peaks in their spectrum. These peaks are qualitatively defined through diagrams of relative probability (probability density function or PDF), but it is difficult to quantify their statistical significance relative to a zircon-forming multipeak event. Therefore, the question arises as to whether we can decipher and characterize a multipeak event in a noncomplex set of detrital zircon U–Pb ages. This work is an attempt to answer the above question by means of a statistical analysis. The objectives are: (1) to determine the most appropriate minimum number of zircon age populations (peaks); (2) to characterize each peak in terms of age and event duration; and (3) to compare results obtained for two datasets showing similar zircon ages. The process starts by using a cluster analysis to group zircon ages into a set of consistent clusters. A Gaussian kernel function is then fitted to each cluster and summed to obtain a theoretical PDF. At the end of the process, the best modelled PDF must coincide with the original PDF at ≥95 %, and the deciphered peaks can then be characterized.

Keywords

Detrital zircon data Population Peaks Comparisons of datasets Gaussian kernel function 

Notes

Acknowledgments

This paper is a contribution to research project GONDWANA-PTDC/CTE-GIX/110426/2009 funded by Fundação para a Ciência e Tecnologia (Portugal). It is a contribution to project PEst-OE/CTE/UI4073/2014.

References

  1. Pereira, M. F., Chichorro, M., Johnston, S. T., Gutiérrez-Alonso, G., Silva, J. B., Linnemann, U., et al. (2012). The missing Rheic Ocean magmatic arcs: Provenance analysis of Late Paleozoic sedimentary clastic rocks of SW Iberia. Gondwana Research,22, 882–891.CrossRefGoogle Scholar
  2. Rosa, D., Finch, A., Andersen, T., & Inverno, C. (2009). U-Pb geochronology and Hf isotope ratios of magmatic zircons from the Iberian Pyrite Belt. Mineralogy and Petrology,95, 47–69.CrossRefGoogle Scholar
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  4. Sircombe, K. N. (2004). AgeDisplay: An EXCEL workbook to evaluate and display univariate geochronological data using binned frequency histograms and probability density distributions. Computers and Geosciences,30, 21–31.CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  • A. Ferreira
    • 1
    Email author
  • C. Lopes
    • 1
  • M. Chichorro
    • 1
  • M. F. Pereira
    • 2
  • A. R. Sola
    • 3
  1. 1.CICEGe, Departamento de Ciências da Terra, Faculdade de Ciências e TecnologiaUniversiadade Nova de LisboaCaparicaPortugal
  2. 2.IDL, Departamento de GeociênciasECT, Universidade de ÉvoraÉvoraPortugal
  3. 3.Unidade de Geologia, LNEGLisbonPortugal

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