Mataranka Springs hydrochemistry time series

\n## **Abstract** \nThis dataset contains the hydrochemical and environmental tracer data of a fortnightly time series and event-driven precipitation data between October 2019 and March 2021 created as part of the Geological and Bioregional Assessment Program (GBA) stage 3 in the Beetaloo Sub-basin. A total of 28 spring samples were collected and analysed for a number of parameters including hydrochemistry (major and minor ions) and the environmental tracers 222Rn, 18O, 2H. Samples are from Bitter Spring (2 locations), Rainbow Spring and Fig Tree Spring at Mataranka. Further 19 rainwater samples were taken at the ranger station in Mataranka and analysed for 18O & 2H. The data showed the variability of Fig-Tree Spring indicating that part of the water discharging is sourced from a swampy upstream area and flows to the spring along a short flow distance. Bitter Spring and Rainbow Spring show steady values hardly influenced by seasons and therefore have mean residence times above 4-5years. Significant values of helium above solubility equilibrium also indicate the presence of an older component, probably circulating on the time scale of centuries.\n\n\n## **Attribution** \nGeological and Bioregional Assessment Program\n\n\n## **History** \nSamples were taken by Mataranka Rangers and sent by post to CSIRO Waite Campus, Adelaide for 222Rn measurement and to CDU in Darwin for 18O, 2H and hydrochemistry measurement. Alkalinity was measured by titration. Stable isotopes 2H and 18O of water were measured on a Picarro Cavity-Ring Down Laser Spectrometer, are calibrated versus VSMOW and given in the usual delta notation. Anions were measured by ion chromatography and cations by ICP-OES. Radon extraction followed the procedure outlined in Leaney & Herczeg (2006) and measurements were done using Liquid Scintillation Spectroscopy on a Quantulus Counter. Data are reported as measured without further post-processing.