Skip to content

Research at St Andrews

Can we extract ultrahigh-temperature conditions from Fe-rich metapelites? An example from the Khondalite Belt, North China Craton

Research output: Contribution to journalArticle

Open Access Status

  • Embargoed (until 29/01/20)

Author(s)

Xianwei Li, Richard William White, Chunjing Wei

School/Research organisations

Abstract

In this study, garnet–sillimanite gneisses at Hongshaba in the eastern segment of the Khondalite Belt, North China Craton (NCC) are interpreted to have experienced ultrahigh-temperature (UHT) metamorphism (980–1040 °C) followed by post-Tmax cooling at pressures of 8–9 kbar to the solidus (810–830 °C), consistent with rare sapphirine-bearing assemblages in surrounding regions. This interpretation is mainly based on the combination of PT fields and garnet Xgr (=Ca/(Ca + Mg + Fe2+)) isopleths on the pseudosection of three garnet–sillimanite gneiss samples. Spinel tends to be enclosed in the outer margins of garnet, commonly closely associated with quartz. We interpret this to reflect the partial break down of garnet along the prograde path during heating with decompression followed by new garnet growth during cooling along an overall clockwise PT evolution. Although Fe-rich UHT metapelites tend to contain neither diagnostic mineral assemblages nor orthopyroxene from which to extract T via Al-in-orthopyroxene thermometry, isopleths of Ca in garnet may aid in retrieving UHT conditions from these compositions. This is attributed to Ca diffusion in garnet being much slower than Fe and Mg diffusion, leading to little change in Ca contents during post-Tmax cooling. LA-ICP-MS U-Pb dating of metamorphic zircon in one garnet–sillimanite gneiss sample yields a mean 207Pb/206Pb age of ca. 1.91 Ga, which is interpreted to record the timing of cooling of the UHT rocks to the solidus. This UHT metamorphism is interpreted to have been generated by mantle-derived magma during a tectonic extension from ca. 1.95 to 1.92 Ga within a post-orogenic setting.
Close

Details

Original languageEnglish
Pages (from-to)228-243
JournalLithos
Volume328-329
Early online date29 Jan 2019
DOIs
Publication statusPublished - Mar 2019

    Research areas

  • Khondalite Belt, North China Craton, Phase equilibrium modelling, Ultrahigh-temperature metamorphism, Zircon geochronology

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

View graph of relations

Related by author

  1. The truth and beauty of chemical potentials

    Powell, R., Evans, K. A., Green, E. C. R. & White, R. W., 2 May 2019, In : Journal of Metamorphic Geology. Early View

    Research output: Contribution to journalArticle

  2. Generation of Earth's early continents from a relatively cool Archean mantle

    Piccolo, A., Palin, R. M., Kaus, B. J. P. & White, R. W., 1 Apr 2019, In : Geochemistry, Geophysics, Geosystems. 20, 4, p. 1679-1697

    Research output: Contribution to journalArticle

  3. Origin, age, and significance of deep-seated granulite-facies migmatites in the Barrow zones of Scotland, Cairn Leuchan, Glen Muick area

    Palin, R. M., Sayed, A. B., White, R. W. & Mertz-kraus, R., Oct 2018, In : Journal of Metamorphic Geology. 36, 8, p. 1071-1096

    Research output: Contribution to journalArticle

  4. New constraints on granulite facies metamorphism and melt production in the Lewisian Complex, northwest Scotland

    Feisel, Y., White, R. W., Palin, R. M. & Johnson, T. E., Aug 2018, In : Journal of Metamorphic Geology. 36, 6, p. 799-819

    Research output: Contribution to journalArticle

Related by journal

  1. Lithos (Journal)

    Anouk Margaretha Borst (Reviewer)
    27 Oct 2017

    Activity: Publication peer-review and editorial work typesPeer review of manuscripts

Related by journal

  1. Dating agpaitic rocks: a multi-system (U/Pb, Sm/Nd, Rb/Sr and 40Ar/39Ar) isotopic study of layered nepheline syenites from the Ilímaussaq complex, Greenland

    Borst, A. M., Waight, T., Finch, A. A., Storey, M. & Le Roux, P., Jan 2019, In : Lithos. 324-325, p. 74-88 15 p.

    Research output: Contribution to journalArticle

  2. Exhumation of Attica high-pressure rocks in a subduction channel: new metamorphic PT constraints from Attica, NW Cyclades, Greece

    Ioannis, B., Evripides, M., Windley Brian, F. & Lamont, T. N., 1 Nov 2019, In : Lithos. In press, 105266.

    Research output: Contribution to journalArticle

  3. Implications of 770 Ma Rhyolitic Tuffs, eastern South China Craton in constraining the tectonic setting of the Nanhua Basin

    Qi, L., Xu, Y., Cawood, P. A., Wang, W. & Du, Y., Jan 2019, In : Lithos. 324-325, p. 842-858

    Research output: Contribution to journalArticle

  4. Apatite: a U-Pb thermochronometer or geochronometer?

    Kirkland, C. L., Yakymchuk, C., Szilas, K., Evans, N., Hollis, J., McDonald, B. & Gardiner, N. J., Oct 2018, In : Lithos. 318-319, p. 143-157 15 p.

    Research output: Contribution to journalArticle

ID: 257592570

Top