Journal metrics

Journal metrics

  • IF value: 3.174 IF 3.174
  • IF 5-year value: 3.841 IF 5-year 3.841
  • CiteScore value: 3.48 CiteScore 3.48
  • SNIP value: 1.078 SNIP 1.078
  • SJR value: 1.981 SJR 1.981
  • IPP value: 3.38 IPP 3.38
  • h5-index value: 42 h5-index 42
  • Scimago H index value: 58 Scimago H index 58
Discussion papers | Copyright
https://doi.org/10.5194/cp-2018-113
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

Technical note 04 Sep 2018

Technical note | 04 Sep 2018

Review status
This discussion paper is a preprint. It is a manuscript under review for the journal Climate of the Past (CP).

Lithium isotopes in dolostone as a palaeo-environmental proxy – An experimental approach

Holly L. Taylor1, Isaac J. Kell Duivestein2, Juraj Farkaš3,4, Martin Dietzel2, and Anthony Dosseto1 Holly L. Taylor et al.
  • 1Wollongong Isotope Geochronology Laboratory, School of Earth & Environmental Sciences, University of Wollongong, Wollongong, NSW, Australia
  • 2Institute of Applied Geosciences, Graz University of Technology, Graz, Austria
  • 3Department of Earth Sciences, University of Adelaide, Adelaide, SA, Australia
  • 4Department of Environmental Geosciences, Faculty of Environmental Seciences, Czech University of Life Sciences Prague, Kamycka 129, Praha – Suchdol, Czech Republic

Abstract. Lithium (Li) isotopes in marine carbonates have considerable potential as a proxy to constrain past changes in silicate weathering fluxes and improve our understanding of Earth’s climate. To date the majority of Li isotope studies on marine carbonates have focussed on calcium carbonates. Determination of the Li isotope fractionation between dolomite and a dolomitizing fluid, would allow us to extend investigations to deep times (i.e., Precambrian) when dolostones were the most abundant marine carbonate archives. Dolostones often contain a significant proportion of detrital silicate material, which dominates the Li budget, thus pre-treatment needs to be designed so that only the isotope composition of the carbonate-associated Li is measured. This study aims to serve two main goals: (1) determining the Li isotope fractionation between Ca-Mg carbonates and solution and (2) to develop a method for leaching the carbonate-associated Li out of dolostone while not affecting that contained within the detrital portion of the rock. We synthesized Ca-Mg carbonates at high temperature (150 to 220°C) and measured the Li isotope composition (δ7Li) of precipitated solids and their respective reactive solutions. The relationship of the Li isotope fractionation factor with temperature was obtained: 103lnαprec-sol=(2.56±0.27)×106T2+(5.8±1.3)

Competitive nucleation and growth between dolomite and magnesite were observed during the experiments, however, without notable effect of their relative proportion on the apparent Li isotope fractionation. We found that Li isotope fractionation between precipitated solid and solution is much greater for Ca-Mg carbonates than for Ca carbonates. If the seawater temperature can be estimated independently, the above equation could be used in conjunction with the Li isotope composition of dolostones to derive those of the precipitating solutions and hence make inferrals about the past oceanic Li cycle.

In addition, we also conducted leaching experiments on a Neoproterozoic dolostone and a Holocene coral. Results show that leaching with 0.05M HCl or 0.5% acetic acid at room temperature for 60min releases Li from the carbonate fraction without significant contribution of Li from the siliciclastic detrital component.

These experimental and analytical developments provide a basis for the use of Li isotopes in dolostones as a palaeo-environmental proxy, which will contribute to further advance our understanding of the evolution of Earth’s surface environments.

Download & links
Holly L. Taylor et al.
Interactive discussion
Status: open (until 30 Oct 2018)
Status: open (until 30 Oct 2018)
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
[Subscribe to comment alert] Printer-friendly Version - Printer-friendly version Supplement - Supplement
Holly L. Taylor et al.
Holly L. Taylor et al.
Viewed
Total article views: 325 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
284 38 3 325 1 1
  • HTML: 284
  • PDF: 38
  • XML: 3
  • Total: 325
  • BibTeX: 1
  • EndNote: 1
Views and downloads (calculated since 04 Sep 2018)
Cumulative views and downloads (calculated since 04 Sep 2018)
Viewed (geographical distribution)
Total article views: 325 (including HTML, PDF, and XML) Thereof 316 with geography defined and 9 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Cited
Saved
No saved metrics found.
Discussed
Latest update: 25 Sep 2018
Publications Copernicus
Download
Short summary
Approximately 600 million years ago, major environmental changes set the course for the emergence of animal life. Lithium (Li) isotopes in calcium carbonates can be used as a proxy to understand changes in the palaeo-environment. We conducted experiments that allow us to use Li isotopes in dolostones to extend our understanding of palaeo-environmental changes deeper into the geological record, where other calcium carbonates archives are not present.
Approximately 600 million years ago, major environmental changes set the course for the...
Citation
Share