Skip to content

Research at St Andrews

Apatite: a new redox proxy for silicic magmas?

Research output: Contribution to journalArticle

Author(s)

A. J. Miles, C. M. Graham, C. J. Hawkesworth, M. R. Gillespie, R. W. Hinton, G. D. Bromiley, EMMAC

Abstract

The oxidation states of magmas provide valuable information about the release and speciation of volatile elements during volcanic eruptions, metallogenesis, source rock compositions, open system magmatic processes, tectonic settings and potentially titanium (Ti) activity in chemical systems used for Ti-dependent geothermometers and geobarometers. In this paper we explore the use of Mn in apatite as an oxybarometer in intermediate and silicic igneous rocks. Increased Mn concentrations in apatite in granitic rocks from the zoned Criffell granitic pluton (southern Scotland) correlate with decreasing Fe2O3 (Fe3+) and Mn in the whole-rock and likely reflect increased Mn2+/Mn3+ and greater compatibility of Mn2+ relative to Mn3+ in apatite under reduced conditions. Fe3+/Fe2+ ratios in biotites have previously been used to calculate oxygen fugacities (fO(2)) in the outer zone granodiorites and inner zone granites where redox conditions have been shown to change from close to the magnetite-hematite buffer to close to the nickel-nickel oxide buffer respectively (Stephens et al., 1985). This trend is apparent in apatite Mn concentrations from a range of intermediate to silicic volcanic rocks that exhibit varying redox states and are shown to vary linearly and negatively with log fO(2), such that

logfO(2) = -0.0022(perpendicular to 0.0003)Mn(ppm) -9.75(perpendicular to 0.46)

Variations in the Mn concentration of apatites appear to be largely independent of differences in the Mn concentration of the melt. Apatite Mn concentrations may therefore provide an independent oxybarometer that is amenable to experimental calibration, with major relevance to studies on detrital mineral suites, particularly those containing a record of early Earth redox conditions, and on the climatic impact of historic volcanic eruptions. (C) 2014 Elsevier Ltd. All rights reserved.

Close

Details

Original languageEnglish
Pages (from-to)101-119
Number of pages19
JournalGeochimica et Cosmochimica Acta
Volume132
DOIs
StatePublished - 1 May 2014

    Research areas

  • RARE-EARTH ELEMENTS, PLASMA-MASS SPECTROMETRY, TI-IN-ZIRCON, OXIDATION-STATE, ELECTRON-MICROPROBE, CONTINENTAL-CRUST, SULFUR EVOLUTION, SYNTHETIC ZIRCON, OXYGEN FUGACITY, GRANITIC-ROCKS

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

View graph of relations

Related by author

  1. Geological archive of the onset of plate tectonics

    Cawood, P. A., Hawkesworth, C. J., Pisarevsky, S. A., Dhuime, B., Capitanio, F. A. & Nebel, O. 13 Nov 2018 In : Philosophical Transactions of the Royal Society. A, Mathematical, Physical and Engineering Sciences . 376, 2132, 30 p., 20170405

    Research output: Contribution to journalArticle

  2. Carbonated mantle domains at the base of the Earth's transition zone

    Sun, W., Hawkesworth, C. J., Yao, C., Zhang, C., Huang, R., Liu, X., Sun, X., Ireland, T., Song, M., Ling, M., Ding, X., Zhang, Z., Fan, W. & Wu, Z. 5 Feb 2018 In : Chemical Geology. 478, p. 69-75

    Research output: Contribution to journalArticle

  3. Continental growth seen through the sedimentary record

    Dhuime, B., Hawkesworth, C. J., Delavault, H. & Cawood, P. A. 15 Jul 2017 In : Sedimentary Geology. 357, p. 16-32 17 p.

    Research output: Contribution to journalArticle

  4. Earth's continental lithosphere through time

    Hawkesworth, C. J., Cawood, P. A., Dhuime, B. & Kemp, T. I. S. Jun 2017 In : Annual Review of Earth and Planetary Sciences.

    Research output: Contribution to journalReview article

Related by journal

  1. Isotopic fractionation of zirconium during magmatic differentiation and the stable isotope composition of the silicate Earth

    Inglis, E., Moynier, F., Creech, J., Deng, Z., Day, J., Teng, F-Z., Bizzarro, M., Jackson, M. & Savage, P. 14 Feb 2019 In : Geochimica et Cosmochimica Acta. In press

    Research output: Contribution to journalArticle

  2. Records of carbon and sulfur cycling during the Silurian Ireviken Event in Gotland, Sweden

    Rose, C., Fischer, W. W., Finnegan, S. & Fike, D. A. 1 Feb 2019 In : Geochimica et Cosmochimica Acta. 246, p. 299-316 18 p.

    Research output: Contribution to journalArticle

  3. Assessing foraminifera biomineralisation models through trace element data of cultures under variable seawater chemistry

    Evans, D., Müller, W. & Erez, J. 8 Mar 2018 In : Geochimica et Cosmochimica Acta. In press

    Research output: Contribution to journalArticle

  4. Coupled Mg/Ca and clumped isotope analyses of foraminifera provide consistent water temperatures

    Breitenbach, S. F. M., Mleneck-Vautravers, M. J., Grauel, A. L., Lo, L., Bernasconi, S. M., Müller, I. A., Rolfe, J., Gázquez, F., Greaves, M. & Hodell, D. A. 1 Sep 2018 In : Geochimica et Cosmochimica Acta. 236, p. 283-296 14 p.

    Research output: Contribution to journalArticle

  5. Prediction of equilibrium isotopic fractionation of the gypsum/bassanite/water system using first-principles calculations

    Liu, T., Artacho, E., Gázquez, F., Walters, G. & Hodell, D. 5 Sep 2018 In : Geochimica et Cosmochimica Acta. In press

    Research output: Contribution to journalArticle

ID: 134776242