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Title: Hydrogen and oxygen stable isotope signatures of goethite hydration waters by thermogravimetry-enabled laser spectroscopy

Abstract

The hydrogen and oxygen stable isotope composition (δ 2H and δ 18O values) of mineral hydration waters can give information on the environment of mineral formation. Here we present and validate an approach for the stable isotope analysis of mineral hydration waters based on coupling a thermogravimetric analyzer with a laser-based isotope ratio infrared spectroscopy instrument (Picarro L-2130i), which we abbreviate as TGA-IRIS. TGA-IRIS generates δ 2H and δ 18O values of liquid water samples with precision for δ 2H of ± 1.2‰, and for δ 18O of ± 0.17‰. For hydration waters in goethite, precision for δ 2H ranges from ± 0.3‰ to 1.6‰, and for δ 18O ranges from ± 0.17‰ to 0.27‰. The ability of TGA-IRIS to generate detailed water yield data and δ 2H and δ 18O values of water at varying temperatures allows for the differentiation of water in varying states of binding on mineral surfaces and within the mineral matrix. TGA-IRIS analyses of hydrogen isotopes in goethite yields δ 2H values that reflect the hydrogen of the OH phase in the mineral and are comparable to that made by IRMS and found in the literature. In contrast, δ 18O values on goethite reflectmore » the oxygen in OH groups bound to Fe (Fe-OH group), and not the oxygen bound only to Fe (Fe-O group) in the mineral crystal lattice, and may not be comparable to literature δ 18O values made by IRMS that reflect the total O in the mineral. TGA-IRIS presents the possibility to isotopically differentiate the various oxygen reservoirs in goethite, which may allow the mineral to be used as a single mineral geothermometer. As a result, TGA-IRIS measurements of hydration waters are likely to open new avenues and possibilities for research on hydrated minerals.« less

Authors:
ORCiD logo [1];  [1];  [1]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1406418
Report Number(s):
LLNL-JRNL-736485
Journal ID: ISSN 0009-2541
Grant/Contract Number:  
AC52-07NA27344
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Chemical Geology
Additional Journal Information:
Journal Volume: 475; Journal Issue: C; Journal ID: ISSN 0009-2541
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 58 GEOSCIENCES; 07 ISOTOPES AND RADIATION SOURCES; Stable isotope hydrology; Paleoclimatology; Dehydroxylation; Mineral-water fractionation; Hydrous minerals

Citation Formats

Oerter, Erik, Singleton, Michael, and Davisson, Lee. Hydrogen and oxygen stable isotope signatures of goethite hydration waters by thermogravimetry-enabled laser spectroscopy. United States: N. p., 2017. Web. doi:10.1016/j.chemgeo.2017.10.025.
Oerter, Erik, Singleton, Michael, & Davisson, Lee. Hydrogen and oxygen stable isotope signatures of goethite hydration waters by thermogravimetry-enabled laser spectroscopy. United States. doi:10.1016/j.chemgeo.2017.10.025.
Oerter, Erik, Singleton, Michael, and Davisson, Lee. Sun . "Hydrogen and oxygen stable isotope signatures of goethite hydration waters by thermogravimetry-enabled laser spectroscopy". United States. doi:10.1016/j.chemgeo.2017.10.025.
@article{osti_1406418,
title = {Hydrogen and oxygen stable isotope signatures of goethite hydration waters by thermogravimetry-enabled laser spectroscopy},
author = {Oerter, Erik and Singleton, Michael and Davisson, Lee},
abstractNote = {The hydrogen and oxygen stable isotope composition (δ2H and δ18O values) of mineral hydration waters can give information on the environment of mineral formation. Here we present and validate an approach for the stable isotope analysis of mineral hydration waters based on coupling a thermogravimetric analyzer with a laser-based isotope ratio infrared spectroscopy instrument (Picarro L-2130i), which we abbreviate as TGA-IRIS. TGA-IRIS generates δ2H and δ18O values of liquid water samples with precision for δ2H of ± 1.2‰, and for δ18O of ± 0.17‰. For hydration waters in goethite, precision for δ2H ranges from ± 0.3‰ to 1.6‰, and for δ18O ranges from ± 0.17‰ to 0.27‰. The ability of TGA-IRIS to generate detailed water yield data and δ2H and δ18O values of water at varying temperatures allows for the differentiation of water in varying states of binding on mineral surfaces and within the mineral matrix. TGA-IRIS analyses of hydrogen isotopes in goethite yields δ2H values that reflect the hydrogen of the OH– phase in the mineral and are comparable to that made by IRMS and found in the literature. In contrast, δ18O values on goethite reflect the oxygen in OH– groups bound to Fe (Fe-OH group), and not the oxygen bound only to Fe (Fe-O group) in the mineral crystal lattice, and may not be comparable to literature δ18O values made by IRMS that reflect the total O in the mineral. TGA-IRIS presents the possibility to isotopically differentiate the various oxygen reservoirs in goethite, which may allow the mineral to be used as a single mineral geothermometer. As a result, TGA-IRIS measurements of hydration waters are likely to open new avenues and possibilities for research on hydrated minerals.},
doi = {10.1016/j.chemgeo.2017.10.025},
journal = {Chemical Geology},
number = C,
volume = 475,
place = {United States},
year = {Sun Oct 22 00:00:00 EDT 2017},
month = {Sun Oct 22 00:00:00 EDT 2017}
}

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