An isotopic and modelling study of flow paths and storage in quaternary calcarenite, SW Australia: implications for speleothem paleoclimate records

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dc.contributor.authorTreble, PCen_AU
dc.contributor.authorBradley, Cen_AU
dc.contributor.authorWood, Aen_AU
dc.contributor.authorBaker, AAen_AU
dc.contributor.authorJex, CNen_AU
dc.contributor.authorFairchild, IJen_AU
dc.contributor.authorGagan, MKen_AU
dc.contributor.authorCowley, Jen_AU
dc.contributor.authorAzcurra, CSen_AU
dc.date.accessioned2015-11-01T00:24:50Zen_AU
dc.date.available2015-11-01T00:24:50Zen_AU
dc.date.issued2013-03-15en_AU
dc.date.statistics2015-10-21en_AU
dc.description.abstractWe investigated the distinctive shallow sub-surface hydrology of the southwest Western Australia (SWWA) dune calcarenite using observed rainfall and rainfall δ18O; soil moisture, cave drip rate and dripwater δ18O over a six-year period: August 2005–March 2012. A lumped parameter hydrological model is developed to describe water fluxes and drip δ18O. Comparison of observed data and model output allow us to assess the critical non-climatic karst hydrological processes that modify the precipitation δ18O signal and discuss the implications for speleothem paleoclimate records from this cave and those with a similar karst setting. Our findings include evidence of multiple reservoirs, characterised by distinct δ18O values and recharge responses (‘low’ and ‘high’ flow sites). Dripwaters exhibit δ18O variations in wet versus dry years at low-flow sites receiving diffuse seepage from the epikarst with an attenuated isotopic composition that approximates mean rainfall. Recharge from high-magnitude rain events is stored in a secondary reservoir which is associated with high-flow dripwater that is 1‰ lower than our monitored low-flow sites (δ18O). One drip site is characterised by mixed-flow behaviour and exhibits a non-linear threshold response after the cessation of drainage from a secondary reservoir following a record dry year (2006). Additionally, our results yield a better understanding of the vadose zone hydrology and dripwater characteristics in Quaternary age dune limestones. We show that flow to our monitored sites is dominated by diffuse flow with inferred transit times of less than one year. Diffuse flow appears to follow vertical preferential paths through the limestone reflecting differences in permeability and deep recharge into the host rock. © 2013, Elsevier Ltd.en_AU
dc.identifier.citationTreble, P. C., Bradley, C., Wood, A., Baker, A., Jex, C. N., Fairchild, I. J., Gagan. M. K., Cowley, J., & Azcurra, C. (2013). An isotopic and modelling study of flow paths and storage in quaternary calcarenite, SW Australia: implications for speleothem paleoclimate records. Quaternary Science Reviews, 64, 90-103. doi:10.1016/j.quascirev.2012.12.015en_AU
dc.identifier.govdoc6208en_AU
dc.identifier.issn0277-3791en_AU
dc.identifier.journaltitleQuaternary Science Reviewsen_AU
dc.identifier.pagination90-103en_AU
dc.identifier.urihttp://dx.doi.org/10.1016/j.quascirev.2012.12.015en_AU
dc.identifier.urihttp://apo.ansto.gov.au/dspace/handle/10238/6365en_AU
dc.identifier.volume64en_AU
dc.language.isoenen_AU
dc.publisherElsevieren_AU
dc.subjectWestern Australiaen_AU
dc.subjectRainen_AU
dc.subjectCavesen_AU
dc.subjectSoilsen_AU
dc.subjectWater reservoirsen_AU
dc.subjectSimulationen_AU
dc.titleAn isotopic and modelling study of flow paths and storage in quaternary calcarenite, SW Australia: implications for speleothem paleoclimate recordsen_AU
dc.typeJournal Articleen_AU
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