Australia's climate, soil and groundwater history: a new facility for the analysis of carbonates

Posted 4 October 2011

Lewis Adler with the MAT-253 mass spectrometer

A new mass spectrometer facility funded by the Australian Research Council has been established within the UNSW Analytical Centre.

Despite recent funding initiatives to better understand and monitor modern day Australian groundwater amounts and fluxes (for example, the National Centre for Groundwater Research and Training), there is still a fundamental lack of knowledge about the relative importance of 'fossil' groundwater.

This 'fossil' water is that recharged to the groundwater in the past, and which we may be unsustainably using today.

Our lack of understanding includes a poor knowledge of the timing of these groundwater recharge events; and the climate regimes responsible.

Fundamentally, the extent to which we are unsustainably mining fossil groundwater is unknown, and carbonate isotope archives can provide us with answers to this key question.

The new mass spectrometer facility can analyse approximately forty samples per day of as little as just 20 micrograms of carbonate material, allowing very high resolution analysis of climate and groundwater history preserved in carbonates.

The facility, a state-of-art Finnigan MAT 253 isotope-ratio mass spectrometer, commenced operation in October 2011 in partnership with researchers at the Universities of Melbourne and Newcastle, and the Australian Nuclear Science and Technology Organisation (ANSTO).

A broad range of carbonates can provide crucial archives of past climate variability from materials such as cave stalagmites, corals, spring deposited travertine, and pedogenic carbonates. This is from the carbon and oxygen that makes up the carbonate, and specifically their stable isotopic composition. The ratio of the stable oxygen isotopes 16O and 18O provide archives of the water conditions at the time of archive deposition, be-it ocean composition (corals) or groundwater recharge and moisture source (stalagmites, soil carbonates). Additionally, the stable carbon isotopes ratio of 12C and 13C in stalagmites and pedogenic carbonates can provide unique records of soil carbon and surface vegetation responses to climate variability in the past, allowing us to link groundwater recharge, climate variability and terrestrial carbon budgets.

Further Information: scientists interested in using this new facility should contact Andy Baker. The technical specifications are a Finnigan MAT 253 Isotope ratio Mass Spectrometer with duel inlet system and Kiel Carbonate Preparation Device.

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