Comparison of δ18O in groundwater and a cave flowstone: improving the interpretation of the speleothem δ18O paleoclimate proxy

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dc.contributor.authorAdler, Len_AU
dc.contributor.authorPriestley, SCen_AU
dc.contributor.authorTreble, PCen_AU
dc.contributor.authorBaker, AAen_AU
dc.contributor.authorHellstrom, JCen_AU
dc.contributor.authorGriffiths, ADen_AU
dc.contributor.authorMeredith, KTen_AU
dc.date.accessioned2023-06-07T03:24:42Zen_AU
dc.date.available2023-06-07T03:24:42Zen_AU
dc.date.issued2019-07-30en_AU
dc.date.statistics2023-03-24en_AU
dc.description.abstractSpeleothems are high-resolution records that can be used for terrestrial paleoclimate reconstruction from their oxygen and carbon isotopes (δ18O and δ13C), and whose deposition is directly related to the groundwater recharge process. Groundwater δ18O records have the potential to provide an important long-term record of past climate, but they are low-resolution records as the isotope signal can be altered during flow within the aquifer. In this study we compare measured δ18O values from both a groundwater record and speleothem record from a flowstone over the past 12,000 years for the first time from south west Western Australia. Flowstones normally form from cave streams or fast dripping seepages and their oxygen isotope composition is sensitive to the extent of kinetic fractionation, determined by water flow rate, as well as, streams or seepages water δ18O composition. In this study comparison of δ18O values from a groundwater record and flowstone enables the source water oxygen isotopic composition to be constrained in order for a more complete interpretation of the higher resolution speleothem record, including the site specific kinetic processes and climatic changes. The flowstone δ18O values appear consistent with millennial variability in recharge δ18O predicted using the groundwater values, although the flowstone oxygen isotopes are generally enriched in 18O compared to the regional groundwater record before ~7.4ka. This offset between the records indicates that flowstone calcite deposition was not in isotopic equilibrium with its source water likely due to low flow regimes and extensive degassing of CO2. According to a model of isotopic disequilibrium that is driven by water supply, the Holocene portion of the flowstone record contains periods of relatively lower isotopic disequilibrium indicating possible higher water supply, and periods of relatively higher isotopic disequilibrium indicating possible lower water supply consistent with local and regional archives.en_AU
dc.identifier.citationAdler, L., Priestley, S., Treble, P., Baker, A., Hellstrom, J., Griffiths, A., & Meredith, K. (2019). Comparison of δ18O in groundwater and a cave flowstone: improving the interpretation of the speleothem δ18O paleoclimate proxy. Paper presented to the 20th INQUA Congress 25th - 31st July 2019, Dublin, Ireland. Retrieved from: https://virtual.oxfordabstracts.com/#/event/public/574/submission/853en_AU
dc.identifier.conferenceenddate31 July 2019en_AU
dc.identifier.conferencename20th INQUA Congressen_AU
dc.identifier.conferenceplaceDublin, Irelanden_AU
dc.identifier.conferencestartdate25 July 2019en_AU
dc.identifier.urihttps://virtual.oxfordabstracts.com/#/event/public/574/submission/853en_AU
dc.identifier.urihttps://apo.ansto.gov.au/handle/10238/15050en_AU
dc.language.isoenen_AU
dc.publisherInternational Union for Quaternary Research (INQUA)en_AU
dc.subjectGround wateren_AU
dc.subjectCavesen_AU
dc.subjectAquifersen_AU
dc.subjectQuaternary perioden_AU
dc.subjectIsotopesen_AU
dc.subjectClimatesen_AU
dc.subjectWestern Australiaen_AU
dc.subjectWateren_AU
dc.titleComparison of δ18O in groundwater and a cave flowstone: improving the interpretation of the speleothem δ18O paleoclimate proxyen_AU
dc.typeConference Presentationen_AU
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