Internal Water Facilitates Thermal Resetting of Clumped Isotopes in Biogenic Aragonite
Abstract Biogenic and inorganic calcium carbonates contain considerable amounts of internal water, both as free and organically associated water. The oxygen isotopic compositions (δ18O) of internal water and hosting carbonate are analyzed for various carbonates before and after heating at 175°C for...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Wiley
2021-05-01
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| Series: | Geochemistry, Geophysics, Geosystems |
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| Online Access: | https://doi.org/10.1029/2021GC009730 |
| _version_ | 1797638134897311744 |
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| author | C. W. Nooitgedacht H. J. L. van der Lubbe M. Ziegler P. T. Staudigel |
| author_facet | C. W. Nooitgedacht H. J. L. van der Lubbe M. Ziegler P. T. Staudigel |
| author_sort | C. W. Nooitgedacht |
| collection | DOAJ |
| description | Abstract Biogenic and inorganic calcium carbonates contain considerable amounts of internal water, both as free and organically associated water. The oxygen isotopic compositions (δ18O) of internal water and hosting carbonate are analyzed for various carbonates before and after heating at 175°C for 90 minutes. During heating, the δ18O values of internal water significantly increased in biogenic aragonites and speleothem calcite, whereas the δ18O carbonate values were lowered. Correspondingly, an aragonitic bivalve’s clumped‐isotope distribution (Δ47) changed during heating, increasing reconstructed paleotemperatures. In contrast, an inorganic aragonite crystal, containing a comparable amount of internal water, showed no oxygen isotope exchange, and its Δ47 values remained unaltered during heating, implying that there is a link between internal oxygen isotope exchange and Δ47 resetting. This alteration process occurred without any detectable transformation from aragonite to calcite. Our results therefore reveal a mechanism that facilitates oxygen isotope exchange between biogenic aragonite and its internal water, while simultaneously resetting the Δ47 values, without affecting mineralogy. Future studies may therefore apply coupled water‐carbonate analyses to scrutinize these kinds of diagenetic alteration processes. It appears that in biogenic aragonites, more carbonate is available for exchange reactions with the internal water reservoir than in inorganic aragonites, a feature that can be attributed to the distribution of organic‐associated water and/or high surface area fluid inclusions. This water‐aragonite exchange occurs at lower temperatures than those required for solid‐state bond reordering at the same timescale, and thus likely has occurred earlier during the burial of biogenic aragonites. |
| first_indexed | 2024-03-11T12:58:06Z |
| format | Article |
| id | doaj.art-004da7d10ad94650887135d8eef94877 |
| institution | Directory Open Access Journal |
| issn | 1525-2027 |
| language | English |
| last_indexed | 2024-03-11T12:58:06Z |
| publishDate | 2021-05-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geochemistry, Geophysics, Geosystems |
| spelling | doaj.art-004da7d10ad94650887135d8eef948772023-11-03T16:55:31ZengWileyGeochemistry, Geophysics, Geosystems1525-20272021-05-01225n/an/a10.1029/2021GC009730Internal Water Facilitates Thermal Resetting of Clumped Isotopes in Biogenic AragoniteC. W. Nooitgedacht0H. J. L. van der Lubbe1M. Ziegler2P. T. Staudigel3Department of Earth Sciences, Geology and Geochemistry Vrije Universiteit Amsterdam Amsterdam The NetherlandsDepartment of Earth Sciences, Geology and Geochemistry Vrije Universiteit Amsterdam Amsterdam The NetherlandsDepartment of Earth Sciences Utrecht University Utrecht The NetherlandsSchool of Earth and Environmental Sciences Cardiff University Cardiff UKAbstract Biogenic and inorganic calcium carbonates contain considerable amounts of internal water, both as free and organically associated water. The oxygen isotopic compositions (δ18O) of internal water and hosting carbonate are analyzed for various carbonates before and after heating at 175°C for 90 minutes. During heating, the δ18O values of internal water significantly increased in biogenic aragonites and speleothem calcite, whereas the δ18O carbonate values were lowered. Correspondingly, an aragonitic bivalve’s clumped‐isotope distribution (Δ47) changed during heating, increasing reconstructed paleotemperatures. In contrast, an inorganic aragonite crystal, containing a comparable amount of internal water, showed no oxygen isotope exchange, and its Δ47 values remained unaltered during heating, implying that there is a link between internal oxygen isotope exchange and Δ47 resetting. This alteration process occurred without any detectable transformation from aragonite to calcite. Our results therefore reveal a mechanism that facilitates oxygen isotope exchange between biogenic aragonite and its internal water, while simultaneously resetting the Δ47 values, without affecting mineralogy. Future studies may therefore apply coupled water‐carbonate analyses to scrutinize these kinds of diagenetic alteration processes. It appears that in biogenic aragonites, more carbonate is available for exchange reactions with the internal water reservoir than in inorganic aragonites, a feature that can be attributed to the distribution of organic‐associated water and/or high surface area fluid inclusions. This water‐aragonite exchange occurs at lower temperatures than those required for solid‐state bond reordering at the same timescale, and thus likely has occurred earlier during the burial of biogenic aragonites.https://doi.org/10.1029/2021GC009730carbonate mineralogyclumped isotopesfluid inclusionsoxygen isotope exchange |
| spellingShingle | C. W. Nooitgedacht H. J. L. van der Lubbe M. Ziegler P. T. Staudigel Internal Water Facilitates Thermal Resetting of Clumped Isotopes in Biogenic Aragonite Geochemistry, Geophysics, Geosystems carbonate mineralogy clumped isotopes fluid inclusions oxygen isotope exchange |
| title | Internal Water Facilitates Thermal Resetting of Clumped Isotopes in Biogenic Aragonite |
| title_full | Internal Water Facilitates Thermal Resetting of Clumped Isotopes in Biogenic Aragonite |
| title_fullStr | Internal Water Facilitates Thermal Resetting of Clumped Isotopes in Biogenic Aragonite |
| title_full_unstemmed | Internal Water Facilitates Thermal Resetting of Clumped Isotopes in Biogenic Aragonite |
| title_short | Internal Water Facilitates Thermal Resetting of Clumped Isotopes in Biogenic Aragonite |
| title_sort | internal water facilitates thermal resetting of clumped isotopes in biogenic aragonite |
| topic | carbonate mineralogy clumped isotopes fluid inclusions oxygen isotope exchange |
| url | https://doi.org/10.1029/2021GC009730 |
| work_keys_str_mv | AT cwnooitgedacht internalwaterfacilitatesthermalresettingofclumpedisotopesinbiogenicaragonite AT hjlvanderlubbe internalwaterfacilitatesthermalresettingofclumpedisotopesinbiogenicaragonite AT mziegler internalwaterfacilitatesthermalresettingofclumpedisotopesinbiogenicaragonite AT ptstaudigel internalwaterfacilitatesthermalresettingofclumpedisotopesinbiogenicaragonite |