Drip water isotopes in semi-arid karst: Implications for speleothem paleoclimatology
| Autor: | R. Ian Acworth, P. W. Graham, Mark O. Cuthbert, Catherine N. Jex, Pauline C. Treble, Andy Baker, Martin S. Andersen |
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| Rok vydání: | 2014 |
| Předmět: |
Hydrology
geography geography.geographical_feature_category Speleothem Groundwater recharge Arid Infiltration (hydrology) Geophysics Space and Planetary Science Geochemistry and Petrology Evapotranspiration otorhinolaryngologic diseases Earth and Planetary Sciences (miscellaneous) Meteoric water Precipitation Water content Geology |
| Zdroj: | Earth and Planetary Science Letters. 395:194-204 |
| ISSN: | 0012-821X |
| DOI: | 10.1016/j.epsl.2014.03.034 |
| Popis: | We report the results of the first multi-year monitoring and modelling study of the isotopic composition of drip waters in a semi-arid karst terrane. High temporal resolution drip rate monitoring combined with monthly isotope drip water and rainfall sampling at Cathedral Cave, Australia, demonstrates that drip water discharge to the cave occurs irregularly, and only after occasional long duration and high volume rainfall events, where the soil moisture deficit and evapotranspiration is overcome. All drip waters have a water isotopic composition that is heavier than the weighted mean annual precipitation, some fall along the local meteoric water line, others trend towards an evaporation water line. It is hypothesised that, in addition to the initial rainfall composition, evaporation of unsaturated zone water, as well as the time between infiltration events, are the dominant processes that determine infiltration water isotopic composition. We test this hypothesis using a soil moisture balance and isotope model. Our research reports, for the first time, the potential role of sub-surface evaporation in altering drip water isotopic composition, and its implications for the interpretation of speleothem δ O 18 records from arid and semi-arid regions. |
| Databáze: | OpenAIRE |
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