Subaqueous speleothems as archives of groundwater recharge on Australia's southern arid margin
<p>As anthropogenic climate change enhances aridity across many regions of the globe, understanding drivers of aridification is more important than ever before. Unfortunately, arid regions globally tend to exhibit a paucity of palaeoclimate records, and the archives that are available typicall...
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Copernicus Publications
2025-05-01
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| Series: | Climate of the Past |
| Online Access: | https://cp.copernicus.org/articles/21/857/2025/cp-21-857-2025.pdf |
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| author | C. N. Gould-Whaley R. N. Drysdale P. C. Treble P. C. Treble J.-H. May S. C. Priestley J. C. Hellstrom C. R. Vardanega C. C. Buswell |
| author_facet | C. N. Gould-Whaley R. N. Drysdale P. C. Treble P. C. Treble J.-H. May S. C. Priestley J. C. Hellstrom C. R. Vardanega C. C. Buswell |
| author_sort | C. N. Gould-Whaley |
| collection | DOAJ |
| description | <p>As anthropogenic climate change enhances aridity across many regions of the globe, understanding drivers of aridification is more important than ever before. Unfortunately, arid regions globally tend to exhibit a paucity of palaeoclimate records, and the archives that are available typically comprise unconsolidated sediments prone to reworking, large dating uncertainties, and ambiguous climatic interpretations. This is certainly true of Australia's vast continental interior, which is dominated by harsh, arid conditions. Mairs Cave, in the southern Ikara-Flinders Ranges (South Australia), is located on the southern margin of the arid zone. In the present day, the cave is largely dry, and there is limited evidence of active speleothem growth. However, historical records and observations throughout the cave indicate that it was periodically flooded, suggesting the local water balance was once much more positive than it is today. The cave contains a curtain of hanging speleothems known as pendulites, which grow subaqueously when submerged in water that is saturated with respect to calcite. Geochemical evidence, including trace element concentrations, uranium isotope ratios, and dead carbon fractions (DCFs), indicates that a rise in the local groundwater during periods of enhanced groundwater recharge is the cause of the cave flooding events that trigger pendulite growth. Uranium–thorium dating of a pendulite retrieved from Mairs Cave has revealed two multi-millennial growth phases (68.5–65.4 and 51.2–42.3 ka) and two short bursts of growth (18.9 and 16.4 ka) during the Last Glacial Period (LGP). The absence of subsequent pendulite growth suggests that strong water deficits under warm Holocene interglacial conditions give rise to episodic, rather than persistent, cave flooding.</p> |
| format | Article |
| id | doaj-art-d0cc634b03ed4349802bfec07945f4ca |
| institution | DOAJ |
| issn | 1814-9324 1814-9332 |
| language | English |
| publishDate | 2025-05-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Climate of the Past |
| spelling | doaj-art-d0cc634b03ed4349802bfec07945f4ca2025-08-20T02:57:17ZengCopernicus PublicationsClimate of the Past1814-93241814-93322025-05-012185787610.5194/cp-21-857-2025Subaqueous speleothems as archives of groundwater recharge on Australia's southern arid marginC. N. Gould-Whaley0R. N. Drysdale1P. C. Treble2P. C. Treble3J.-H. May4S. C. Priestley5J. C. Hellstrom6C. R. Vardanega7C. C. Buswell8School of Geography, Earth and Atmospheric Science, University of Melbourne, Parkville, 3010, AustraliaSchool of Geography, Earth and Atmospheric Science, University of Melbourne, Parkville, 3010, AustraliaEnvironment Research Group, Australian Nuclear Science and Technology Organisation, Lucas Heights, 2234, AustraliaSchool of Biological, Earth and Environmental Sciences, University of New South Wales, Kensington, 2052, AustraliaSchool of Geography, Earth and Atmospheric Science, University of Melbourne, Parkville, 3010, AustraliaDrought Resilience Mission, Commonwealth Scientific and Industrial Research Organisation, Adelaide, 5000, AustraliaSchool of Geography, Earth and Atmospheric Science, University of Melbourne, Parkville, 3010, AustraliaEnvironment Research Group, Australian Nuclear Science and Technology Organisation, Lucas Heights, 2234, AustraliaCollege of Humanities, Arts and Social Sciences, Flinders University, Adelaide, 5001, Australia<p>As anthropogenic climate change enhances aridity across many regions of the globe, understanding drivers of aridification is more important than ever before. Unfortunately, arid regions globally tend to exhibit a paucity of palaeoclimate records, and the archives that are available typically comprise unconsolidated sediments prone to reworking, large dating uncertainties, and ambiguous climatic interpretations. This is certainly true of Australia's vast continental interior, which is dominated by harsh, arid conditions. Mairs Cave, in the southern Ikara-Flinders Ranges (South Australia), is located on the southern margin of the arid zone. In the present day, the cave is largely dry, and there is limited evidence of active speleothem growth. However, historical records and observations throughout the cave indicate that it was periodically flooded, suggesting the local water balance was once much more positive than it is today. The cave contains a curtain of hanging speleothems known as pendulites, which grow subaqueously when submerged in water that is saturated with respect to calcite. Geochemical evidence, including trace element concentrations, uranium isotope ratios, and dead carbon fractions (DCFs), indicates that a rise in the local groundwater during periods of enhanced groundwater recharge is the cause of the cave flooding events that trigger pendulite growth. Uranium–thorium dating of a pendulite retrieved from Mairs Cave has revealed two multi-millennial growth phases (68.5–65.4 and 51.2–42.3 ka) and two short bursts of growth (18.9 and 16.4 ka) during the Last Glacial Period (LGP). The absence of subsequent pendulite growth suggests that strong water deficits under warm Holocene interglacial conditions give rise to episodic, rather than persistent, cave flooding.</p>https://cp.copernicus.org/articles/21/857/2025/cp-21-857-2025.pdf |
| spellingShingle | C. N. Gould-Whaley R. N. Drysdale P. C. Treble P. C. Treble J.-H. May S. C. Priestley J. C. Hellstrom C. R. Vardanega C. C. Buswell Subaqueous speleothems as archives of groundwater recharge on Australia's southern arid margin Climate of the Past |
| title | Subaqueous speleothems as archives of groundwater recharge on Australia's southern arid margin |
| title_full | Subaqueous speleothems as archives of groundwater recharge on Australia's southern arid margin |
| title_fullStr | Subaqueous speleothems as archives of groundwater recharge on Australia's southern arid margin |
| title_full_unstemmed | Subaqueous speleothems as archives of groundwater recharge on Australia's southern arid margin |
| title_short | Subaqueous speleothems as archives of groundwater recharge on Australia's southern arid margin |
| title_sort | subaqueous speleothems as archives of groundwater recharge on australia s southern arid margin |
| url | https://cp.copernicus.org/articles/21/857/2025/cp-21-857-2025.pdf |
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