Sadekov, A and Lloyd, NS and Misra, S and D'Olivo, JP and McCulloch, M (2020) In situ Mg isotope measurements of biogenic carbonates using laser ablation multi-collector inductively coupled plasma mass spectrometry: A new tool to understand biomineralisation. In: Rapid Communications in Mass Spectrometry, 34 (23).
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Abstract
Rationale: Magnesium is one of the most abundant elements in the earth's crust and in seawater. Fractionation of its stable isotopes has been shown to be a useful indicator of many geological, chemical, and biological processes. For example, biogenic carbonates display an ~5‰ range of δ26Mg values, which is attributed to variable degrees of biological control on Mg ions during biomineralisation. Understanding this biological control is essential for developing proxies based on biogenic carbonates. Methods: In this work, we present a new approach of measuring Mg isotopes in biogenic carbonates using Laser Ablation Multi-Collector Inductively Coupled Plasma Mass Spectrometry (LA-MC-ICPMS). Results: Our results show that this microanalytical approach provides relatively fast, high spatial resolution (<0.2 μm) measurements with high precision and accuracy down to 0.2‰ (2SE). To achieve high levels of precision and accuracy, baseline interferences need to be monitored and a carbonate standard with a relatively low trace metal composition similar to biogenic carbonates should be used. We also demonstrate that the matrix effect on Mg isotopes in carbonates with low Fe and Mn is limited to less than 0.2‰ fractionation under different laser parameters and low oxide condition (<0.3% ThO/Th). Conclusions: Our newly developed LA-MC-ICPMS method and its applications to biogenic carbonates show significant advantages provided by the microanalytical approach in understanding complex processes of biomineralisation in marine calcifiers. © 2020 John Wiley & Sons, Ltd.
| Item Type: | Journal Article |
|---|---|
| Publication: | Rapid Communications in Mass Spectrometry |
| Publisher: | John Wiley and Sons Ltd |
| Additional Information: | The copyright for this article belongs to The John Wiley and Sons Ltd. |
| Keywords: | carbonic acid; isotope; magnesium, biomineralization; chemistry; laser; mass spectrometry; metabolism; procedures, Biomineralization; Carbonates; Isotopes; Lasers; Magnesium; Mass Spectrometry |
| Department/Centre: | Division of Mechanical Sciences > Centre for Earth Sciences |
| Date Deposited: | 09 Jan 2023 09:18 |
| Last Modified: | 09 Jan 2023 09:18 |
| URI: | https://eprints.iisc.ac.in/id/eprint/78944 |
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