Eight-years of cave monitoring at Golgotha Cave, SW Australia: implications for speleothem paleoclimate records
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Date
2014-06-29
Journal Title
Journal ISSN
Volume Title
Publisher
Australasian Quaternary Association Inc
Abstract
Speleothems are an important archive of paleoenvironmental information but a thorough
understanding of processes are necessary for their interpretation. In order to better understand
speleothem records from the climatically-sensitive southwest region of WA, we have conducted a
detailed eight-year monitoring study at Golgotha Cave, southwest WA.
Oxygen isotopic data demonstrated that the majority of water moved through the porous Quaternary
calcarenite as matrix-flow with an inferred transit time of <1 year. A zone of high-flow dripwater is fed
by high-magnitude rainfall events (Treble et al., 2013). Prior calcite precipitation (PCP) signals of
increased Mg/Ca and Sr/Ca in dripwater are attributed to stalactite deposition. This signal is
enhanced at low-flow sites and minimised at the high-flow site as degassing and subsequent
stalactite deposition are a function of drip interval. Long-term rising trends found in most solutes are
attributed via a mass-balance approach to increasing forest bioproductivity, consistent with an
increase in forest understorey following a low-intensity burn in 2006.
A fundamental message from this study is that individual speleothem records from within Golgotha
Cave will differ, e.g. speleothem δ18O at our high-flow site is biased to recording high-magnitude
rainfall events, whilst PCP will be the main driver of speleothem Mg/Ca and Sr/Ca at low-flow sites.
Forest biomass appears to be modulating transpiration-sensitive ions and these may serve as an
indicator of fire history.
Description
Keywords
Western Australia, Caves, Forests, Oxygen, Monitoring, Water, Quaternary period, Rain
Citation
Treble, P. C., Fairchild, I. J., Baker, A., Bradley, C., Wood, A., & McGuire, L. (2014). Eight-years of cave monitoring at Golgotha Cave, SW Australia: implications for speleothem paleoclimate records. Paper presented at the AQUA Biennial Meeting The Grand Hotel, Mildura, 29th June - 4th July, 2014.