Speleothem ‘uptick’ supports reduction in rainfall recharge to groundwater is unprecedented for last 800 years, SW Western Australia
Loading...
Date
2022-12-06
Journal Title
Journal ISSN
Volume Title
Publisher
Australasian Quaternary Association
Abstract
Southwestern Australia relies significantly on groundwater for domestic and industrial purposes. As water availability has decreased and is projected to continue to decrease with climate change, it is critical to understand the impacts of climate change on groundwater recharge for this region. Speleothem (e.g. cave stalagmites) deposition is directly related to groundwater recharge, as they form from rainfall which has infiltrated into the vadose zone and represent periods of potential aquifer recharge. In this study, modern speleothems from five caves record a consistent response to a sustained decrease in rainfall across south-west Australia that began in the 1970s, characterised by an ‘uptick’ in the speleothem oxygen isotopic composition (Priestley et al., 2022). It is demonstrated that the ‘uptick’ is in response to the shallow karst aquifers becoming disconnected from rainfall recharge due to regional drying. As the coastal caves are located in highly permeable host rock along the wettest zone of the region, our findings imply that rainfall recharge to groundwater across the southwest Australian region may no longer be reliably occurring. The paleo-record for speleothems from south-west Australia (Treble et al., 2022) provides a longer-term context to assess the recent isotopic uptick against and confirms that no similar events are seen in the last 800 years in stalagmites from the region.
Description
Keywords
Rain water, Australia, Ground water, Oxygen isotopes, Caves, Rocks, Deposition, Climates
Citation
Priestley, S., Treble, P., Baker, A., Griffiths, A., Abram, N., & Meredith, K. (2022). Speleothem ‘uptick’ supports reduction in rainfall recharge to groundwater is unprecedented for last 800 years, SW Western Australia. Paper presented to the AQUA 2022 Conference, 6-8th December, Adelaide, (pp. 87-88). Retrieved from: https://aqua.org.au/conference/aqua-2022/aqua-2022-conference-program-and-abstracts/