Skip to content

Research at St Andrews

Mapping temporal and spatial patterns of zircon U-Pb disturbance: a Yilgarn Craton case study

Research output: Contribution to journalArticle

DOI

Author(s)

C. L. Kirkland, F. Abello, M. Danišík, N. J. Gardiner, C. Spencer

School/Research organisations

Abstract

The zircon U-Pb system is a robust geochronometer, however disturbance to this system can be widely diagnosed on U-Pb concordia diagrams where it is typically interpreted as a consequence of radiogenic-Pb loss. In many cases, removal of radiogenic-Pb is not complete, and Discordia regressions on concordia diagrams may then potentially track both the original age of crystallization of the rock, and the timing of isotopic disturbance. However, U-Pb disturbance, resulting in normal discordance, can also be driven by U gain. In this contribution, we expand on a novel approach to determine the most pervasive time of U-Pb disturbance in a sample. We introduce the Concordant-Discordant Comparison (CDC) test which evaluates the similarity between a sample's concordant age structure and a modelled age structure, from discordant analyses, over a wide range of potential disturbance times. The closest similarity in concordant and discordant age populations as derived from a specified time of elemental mobility, is interpreted as the best estimate for the time of U-Pb disturbance. The CDC test is appropriate for magmatic as well as detrital samples, and yields dates that can be spatially interpolated to produce regional maps that define domains of U-Pb disturbance.


We highlight the application of the CDC test using a case study from the Eastern Goldfields Superterrane of the Yilgarn Craton, Western Australia. U-Pb SIMS analysis of 95 zircon samples from across the Eastern Goldfields Superterrane reveals two dominant times of U-Pb disturbance – recent and at ~ 600 Ma. The ~ 600 Ma time of U-Pb disturbance shows a statistically significant spatial relationship to a buried set of undated dykes (the Cosmo Newbery Dyke Suite), which are apparent in geophysical images. Thermal modelling indicates dyke temperatures alone are insufficient to cause widespread Pb loss in host rock zircon. We therefore suggest dyke emplacement caused U-Pb disturbance through reactive fluids leaching radiogenic-Pb. Additionally, we use the difference between the measured and calculated zircon Th/U ratio to distinguish between Pb loss and elemental gain processes, as the calculated Th/U ratio derived from 208Pb/206Pb will only match measured Th/U where no later addition or loss of Th or U has occurred. CDC modelling of discordant U-Pb zircon analyses may provide a means to recognise the distal footprint of otherwise difficult to date tectonothermal events and extract useful information from often discarded analyses.

Close

Details

Original languageEnglish
Pages (from-to)39-47
Number of pages9
JournalGondwana Research
Volume52
Early online date31 Aug 2017
DOIs
Publication statusPublished - Dec 2017

    Research areas

  • Discordant, Geochronology, Pb-loss, U-Pb, Zircon

Discover related content
Find related publications, people, projects and more using interactive charts.

View graph of relations

Related by author

  1. Mesoarchean partial melting of mafic crust and tonalite production during high-T–low-P stagnant tectonism, Akia Terrane, West Greenland

    Yakymchuk, C., Kirkland, C. L., Hollis, J. A., Kendrick, J., Gardiner, N. J. & Szilas, K., 8 Jan 2020, In : Precambrian Research. In press

    Research output: Contribution to journalArticle

  2. A window into an ancient backarc? The magmatic and metamorphic history of the Fraser Zone, Western Australia

    Glasson, K. J., Johnson, T. E., Kirkland, C. L., Gardiner, N. J., Clark, C., Blereau, E., Hartnady, M. I. H., Spaggiari, C. & Smithies, H., Apr 2019, In : Precambrian Research. 323, p. 55-69 15 p.

    Research output: Contribution to journalArticle

  3. Building Mesoarchaean crust upon Eoarchaean roots: the Akia Terrane, West Greenland

    Gardiner, N. J., Kirkland, C. L., Hollis, J., Szilas, K., Steenfelt, A., Yakymchuk, C. & Heide-Jørgensen, H., Mar 2019, In : Contributions to Mineralogy and Petrology. 174, 20.

    Research output: Contribution to journalArticle

  4. Zircon U–Pb, Lu–Hf and O isotopes from the 3414 Ma Strelley Pool Formation, East Pilbara Terrane, and the Palaeoarchaean emergence of a cryptic cratonic core

    Gardiner, N. J., Wacey, D., Kirkland, C. L., Johnson, T. E. & Jeon, H., Feb 2019, In : Precambrian Research. 321, p. 64-84 21 p.

    Research output: Contribution to journalArticle

  5. Secular change in TTG compositions: implications for the evolution of Archaean geodynamics

    Johnson, T. E., Kirkland, C. L., Gardiner, N. J., Brown, M., Smithies, R. H. & Santosh, M., 1 Jan 2019, In : Earth and Planetary Science Letters. 505, p. 65-75 11 p.

    Research output: Contribution to journalArticle

Related by journal

  1. Evolution of the Mozambique Belt in Malawi constrained by granitoid U-Pb, Sm-Nd and Lu-Hf isotopic data

    Manda, B. W. C., Cawood, P. A., Spencer, C. J., Prave, T., Robinson, R. & Roberts, N. M. W., 29 Nov 2018, In : Gondwana Research. In press

    Research output: Contribution to journalArticle

  2. The crustal architecture of Myanmar imaged through zircon U-Pb, Lu-Hf and O isotopes: tectonic and metallogenic implications

    Gardiner, N. J., Searle, M. P., Morley, C. K., Robb, L. J., Whitehouse, M. J., Roberts, N. M. W., Kirkland, C. L. & Spencer, C. J., Oct 2018, In : Gondwana Research. 62, p. 27-60 34 p.

    Research output: Contribution to journalReview article

  3. From convergent plate margin to arc-continent collision: formation of the Kenting Mélange, southern Taiwan

    Zhang, X., Cawood, P. A., Huang, C-Y., Wang, Y., Yan, Y., Santosh, M., Chen, W. & Yu, M., Oct 2016, In : Gondwana Research. 38, p. 171-182 12 p.

    Research output: Contribution to journalArticle

ID: 261164562

Top