BIROn - Birkbeck Institutional Research Online

    Using Mg Isotopes to estimate natural Calcite compositions and precipitation rates during the 2010 Eyjafjallajökull eruption

    Pogge von Strandmann, Philip A.E. and Olsson, J. and Luu, T.-H. and Gislason, S. and Burton, K. (2019) Using Mg Isotopes to estimate natural Calcite compositions and precipitation rates during the 2010 Eyjafjallajökull eruption. Frontiers in Earth Science 7 (6), ISSN 2296-6463.

    [img] Text
    Eyjafjallajokull Mg resubmission.pdf - Author's Accepted Manuscript
    Restricted to Repository staff only

    Download (411kB)
    [img]
    Preview
    Text
    26099.pdf - Published Version of Record
    Available under License Creative Commons Attribution.

    Download (1MB) | Preview

    Abstract

    Chemical weathering of silicate rocks is a key control on the long-term climate, via drawdown of atmospheric CO2. Magnesium isotopes are increasingly being used to trace weathering, but are often complicated by several coincident fractionating processes. Here we examine Mg isotope ratios of waters stemming from beneath lava flows from the 2010 Eyjafjallajökull eruption. Travertine calcite was observed directly precipitating from these high-TDS (total dissolved solids) waters, and were also sampled. This system therefore provides the opportunity to study natural Mg isotope fractionation by calcite. Riverine δ26Mg increase from −2.37 to +0.43% with flow distance, as isotopically light travertine precipitates (δ26Mg = −3.38 to −3.94%). The solution Mg isotope ratios also co-vary with pH, calcite saturation indices and Sr/Ca ratios, strongly indicating that they are dominantly controlled by carbonate precipitation. Using experimental isotopic fractionation factors and the measured δ26Mg values, we can predict the compositions of the precipitated travertines that are within uncertainty of the directly measured travertines. Hence, in some systems, Mg isotopes can be used to quantify carbonate precipitation.

    Metadata

    Item Type: Article
    Keyword(s) / Subject(s): weathering, carbonate, travertine, magnesium isotopes, basalt
    School: Birkbeck Schools and Departments > School of Science > Earth and Planetary Sciences
    Depositing User: Philip Pogge Von Strandmann
    Date Deposited: 04 Feb 2019 15:48
    Last Modified: 25 Jan 2020 01:24
    URI: http://eprints.bbk.ac.uk/id/eprint/26099

    Statistics

    Downloads
    Activity Overview
    84Downloads
    45Hits

    Additional statistics are available via IRStats2.

    Archive Staff Only (login required)

    Edit/View Item Edit/View Item