Home > Research > Publications & Outputs > Sulphate partitioning into calcite

Electronic data

  • Manuscript GCA-D-17-00001

    Rights statement: This is the author’s version of a work that was accepted for publication in Geochimica et Cosmochimica Acta. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Geochimica et Cosmochimica Acta, 226, 2018 DOI: 10.1016/j.jca.2018.01.020

    Accepted author manuscript, 2.78 MB, PDF document

    Available under license: CC BY-NC-ND: Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License

Links

Text available via DOI:

View graph of relations

Sulphate partitioning into calcite: Experimental verification of pH control and application to seasonality in speleothems

Research output: Contribution to Journal/MagazineJournal articlepeer-review

Published

Standard

Sulphate partitioning into calcite: Experimental verification of pH control and application to seasonality in speleothems. / Wynn, Peter Michael; Fairchild, Ian; Borsato, Andrea et al.
In: Geochimica et Cosmochimica Acta, Vol. 226, 01.04.2018, p. 69-83.

Research output: Contribution to Journal/MagazineJournal articlepeer-review

Harvard

Wynn, PM, Fairchild, I, Borsato, A, Spötl, C, Hartland, A, Baker, A, Frisia, S & Baldini, JUL 2018, 'Sulphate partitioning into calcite: Experimental verification of pH control and application to seasonality in speleothems', Geochimica et Cosmochimica Acta, vol. 226, pp. 69-83. https://doi.org/10.1016/j.gca.2018.01.020

APA

Wynn, P. M., Fairchild, I., Borsato, A., Spötl, C., Hartland, A., Baker, A., Frisia, S., & Baldini, J. U. L. (2018). Sulphate partitioning into calcite: Experimental verification of pH control and application to seasonality in speleothems. Geochimica et Cosmochimica Acta, 226, 69-83. https://doi.org/10.1016/j.gca.2018.01.020

Vancouver

Wynn PM, Fairchild I, Borsato A, Spötl C, Hartland A, Baker A et al. Sulphate partitioning into calcite: Experimental verification of pH control and application to seasonality in speleothems. Geochimica et Cosmochimica Acta. 2018 Apr 1;226:69-83. Epub 2018 Feb 2. doi: 10.1016/j.gca.2018.01.020

Author

Wynn, Peter Michael ; Fairchild, Ian ; Borsato, Andrea et al. / Sulphate partitioning into calcite : Experimental verification of pH control and application to seasonality in speleothems. In: Geochimica et Cosmochimica Acta. 2018 ; Vol. 226. pp. 69-83.

Bibtex

@article{cef26b980cf94c05b98c8ea516332cee,
title = "Sulphate partitioning into calcite: Experimental verification of pH control and application to seasonality in speleothems",
abstract = "Carbonate-associated sulphate (CAS) is a useful carrier of palaeoenvironmental information throughout the geologic record, particularly through its stable isotope composition. However, a paucity of experimental data restricts quantitative understanding of sulphate incorporation into carbonates, and consequently CAS concentrations and their diagenetic modifications are rarely interpreted. However, in the case of calcite speleothems, the remarkably high-resolution CAS records which are obtainable via modern microanalytical techniques represent a potentially invaluable source of palaeoenvironmental information. Here, we describe the results of controlled experiments of sulphate co-precipitation with calcite in freshwater solutions where pH, saturation state, and sulphate concentration were varied independently of each other. Solution pH is confirmed as the principal control on sulphate incorporation into calcite. The relative efficiency of incorporation was calculated as a partition coefficient DSO4 = (mSO4/mCO3)solid / (mSO4/mCO3)solution. High crystal growth rates (driven by either pH or saturation state) encouraged higher values of DSO4 because of an increasing concentration of defect sites on crystal surfaces. At low growth rates, DSO4 was reduced due to an inferred competition between sulphate and bicarbonate at the calcite surface. These experimental results are applied to understand the incorporation of sulphate into speleothem calcite. The experimentally determined pH-dependence suggests that strong seasonal variations in cave air PCO2 could account for annual cycles in sulphate concentration observed in stalagmites. Our new experimentally determined values of DSO4 were compared with DSO4 values calculated from speleothem-drip water monitoring from two caves within the Austrian and Italian Alps. At Obir cave, Austria, DSO4 (x105) varies between 11.1 (winter) and 9.0 (summer) and the corresponding figures for Ernesto cave, Italy, are 15.4 (winter) and 14.9 (summer). These values approximate predicted DSO4 values based on our chamber experiments containing both low (2 ppm) and high (20 ppm) sulphate concentrations. Our experimental values of DSO4 obtained at crystal growth rates typical of stalagmites, closely match those observed in other cave sites from around the world. This validates the universality of the controls behind DSO4 and will enhance the use of speleothem CAS as a palaeoenvironmental proxy.",
keywords = "Carbonate associated sulphate, Speleothem, Partition coefficients, Sulphate, pH",
author = "Wynn, {Peter Michael} and Ian Fairchild and Andrea Borsato and Christoph Sp{\"o}tl and Adam Hartland and Andy Baker and S Frisia and Baldini, {James U. L.}",
note = "This is the author{\textquoteright}s version of a work that was accepted for publication in Geochimica et Cosmochimica Acta. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Geochimica et Cosmochimica Acta, 226, 2018 DOI: 10.1016/j.jca.2018.01.020",
year = "2018",
month = apr,
day = "1",
doi = "10.1016/j.gca.2018.01.020",
language = "English",
volume = "226",
pages = "69--83",
journal = "Geochimica et Cosmochimica Acta",
issn = "0016-7037",
publisher = "Elsevier Limited",

}

RIS

TY - JOUR

T1 - Sulphate partitioning into calcite

T2 - Experimental verification of pH control and application to seasonality in speleothems

AU - Wynn, Peter Michael

AU - Fairchild, Ian

AU - Borsato, Andrea

AU - Spötl, Christoph

AU - Hartland, Adam

AU - Baker, Andy

AU - Frisia, S

AU - Baldini, James U. L.

N1 - This is the author’s version of a work that was accepted for publication in Geochimica et Cosmochimica Acta. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Geochimica et Cosmochimica Acta, 226, 2018 DOI: 10.1016/j.jca.2018.01.020

PY - 2018/4/1

Y1 - 2018/4/1

N2 - Carbonate-associated sulphate (CAS) is a useful carrier of palaeoenvironmental information throughout the geologic record, particularly through its stable isotope composition. However, a paucity of experimental data restricts quantitative understanding of sulphate incorporation into carbonates, and consequently CAS concentrations and their diagenetic modifications are rarely interpreted. However, in the case of calcite speleothems, the remarkably high-resolution CAS records which are obtainable via modern microanalytical techniques represent a potentially invaluable source of palaeoenvironmental information. Here, we describe the results of controlled experiments of sulphate co-precipitation with calcite in freshwater solutions where pH, saturation state, and sulphate concentration were varied independently of each other. Solution pH is confirmed as the principal control on sulphate incorporation into calcite. The relative efficiency of incorporation was calculated as a partition coefficient DSO4 = (mSO4/mCO3)solid / (mSO4/mCO3)solution. High crystal growth rates (driven by either pH or saturation state) encouraged higher values of DSO4 because of an increasing concentration of defect sites on crystal surfaces. At low growth rates, DSO4 was reduced due to an inferred competition between sulphate and bicarbonate at the calcite surface. These experimental results are applied to understand the incorporation of sulphate into speleothem calcite. The experimentally determined pH-dependence suggests that strong seasonal variations in cave air PCO2 could account for annual cycles in sulphate concentration observed in stalagmites. Our new experimentally determined values of DSO4 were compared with DSO4 values calculated from speleothem-drip water monitoring from two caves within the Austrian and Italian Alps. At Obir cave, Austria, DSO4 (x105) varies between 11.1 (winter) and 9.0 (summer) and the corresponding figures for Ernesto cave, Italy, are 15.4 (winter) and 14.9 (summer). These values approximate predicted DSO4 values based on our chamber experiments containing both low (2 ppm) and high (20 ppm) sulphate concentrations. Our experimental values of DSO4 obtained at crystal growth rates typical of stalagmites, closely match those observed in other cave sites from around the world. This validates the universality of the controls behind DSO4 and will enhance the use of speleothem CAS as a palaeoenvironmental proxy.

AB - Carbonate-associated sulphate (CAS) is a useful carrier of palaeoenvironmental information throughout the geologic record, particularly through its stable isotope composition. However, a paucity of experimental data restricts quantitative understanding of sulphate incorporation into carbonates, and consequently CAS concentrations and their diagenetic modifications are rarely interpreted. However, in the case of calcite speleothems, the remarkably high-resolution CAS records which are obtainable via modern microanalytical techniques represent a potentially invaluable source of palaeoenvironmental information. Here, we describe the results of controlled experiments of sulphate co-precipitation with calcite in freshwater solutions where pH, saturation state, and sulphate concentration were varied independently of each other. Solution pH is confirmed as the principal control on sulphate incorporation into calcite. The relative efficiency of incorporation was calculated as a partition coefficient DSO4 = (mSO4/mCO3)solid / (mSO4/mCO3)solution. High crystal growth rates (driven by either pH or saturation state) encouraged higher values of DSO4 because of an increasing concentration of defect sites on crystal surfaces. At low growth rates, DSO4 was reduced due to an inferred competition between sulphate and bicarbonate at the calcite surface. These experimental results are applied to understand the incorporation of sulphate into speleothem calcite. The experimentally determined pH-dependence suggests that strong seasonal variations in cave air PCO2 could account for annual cycles in sulphate concentration observed in stalagmites. Our new experimentally determined values of DSO4 were compared with DSO4 values calculated from speleothem-drip water monitoring from two caves within the Austrian and Italian Alps. At Obir cave, Austria, DSO4 (x105) varies between 11.1 (winter) and 9.0 (summer) and the corresponding figures for Ernesto cave, Italy, are 15.4 (winter) and 14.9 (summer). These values approximate predicted DSO4 values based on our chamber experiments containing both low (2 ppm) and high (20 ppm) sulphate concentrations. Our experimental values of DSO4 obtained at crystal growth rates typical of stalagmites, closely match those observed in other cave sites from around the world. This validates the universality of the controls behind DSO4 and will enhance the use of speleothem CAS as a palaeoenvironmental proxy.

KW - Carbonate associated sulphate

KW - Speleothem

KW - Partition coefficients

KW - Sulphate

KW - pH

U2 - 10.1016/j.gca.2018.01.020

DO - 10.1016/j.gca.2018.01.020

M3 - Journal article

VL - 226

SP - 69

EP - 83

JO - Geochimica et Cosmochimica Acta

JF - Geochimica et Cosmochimica Acta

SN - 0016-7037

ER -