Chen, X;
Zhou, Y;
(2023)
Effective Leaching of Argillaceous and Dolomitic Carbonate Rocks for Strontium Isotope Stratigraphy.
Geostandards and Geoanalytical Research
10.1111/ggr.12531.
(In press).
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Abstract
Various methods have been developed to extract a primary seawater Sr isotope signal from carbonate rocks for strontium isotope stratigraphy. However, there is little consensus around the best method due to variable sample purity and mineralogy. For this study, we applied sequential leaching to a range of rock samples in order to explore strontium isotope leaching systematics of less favoured argillaceous and dolomitic limestone samples. Following an ammonium acetate (NH4Ac) prewash that removed ~ 10% of the carbonate fraction, a subsequent dilute acetic acid leach (10–30% aliquot) was shown to extract the lowest, demonstrably least altered seawater 87Sr/86Sr isotope ratios, along with in most cases seawater-like rare earth element (REE) plus yttrium (Y) patterns with the highest Y/Ho ratios (mostly > 36). Subsequent dissolution steps exhibited significantly elevated 87Sr/86Sr isotope ratios, Rb/Sr, Al/Ca and Mg/Ca ratios, indicating greater contributions from aluminosilicates and dolomite in the leachates. The new dissolution method by comparison significantly increases the likelihood of obtaining primary seawater 87Sr/86Sr isotope ratios from argillaceous and dolomitic limestones where the other established procedures failed. Broad application of this approach could improve the temporal resolution of the seawater Sr isotope curve, especially where high purity limestone samples are scarce.
| Type: | Article |
|---|---|
| Title: | Effective Leaching of Argillaceous and Dolomitic Carbonate Rocks for Strontium Isotope Stratigraphy |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1111/ggr.12531 |
| Publisher version: | https://doi.org/10.1111/ggr.12531 |
| Language: | English |
| Additional information: | © 2023 The Authors. Geostandards and Geoanalytical Research published by John Wiley & Sons Ltd on behalf of International Association of Geoanalysts. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
| Keywords: | Dissolution method, strontium isotopes, argillaceous limestone, dolomitic limestone |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Earth Sciences |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10183439 |
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