Beetaloo cores chemical data

Abstract

This dataset contains the chemical and strontium isotope data of a selection of cores and cuttings from the Beetaloo Sub-Basin, which were assessed from the core library of the Northern Territory Geological Survey. A total of 5 bores (Amungee NW-1, Beetaloo W1, BH 1, 12BC001, 12LE001) were sampled for either cuttings or parts of the core. These were for their elemental content by cation and Sr isotope analysis after digestion with Aqua Regia - for carbonate samples - or HF digestion - for samples with higher silicate contents such as basalts and sandstones below the Cambrian Limestone Aquifer (CLA). Further elemental analyses, especially uranium and thorium analysis were performed using XRF analysis at CSIRO Mineral Resources.

The data showed that the aquifer variability for strontium isotopes is much higher than the groundwater variability (as expected) but also that waters in the CLA have a strontium isotope range that differs from the one of the aquifer rock. Furthermore the analyses allowed estimating the insitu production of helium from radioactive decay of U and Th in the host rock and demonstrated that the high helium concentrations found in groundwater could not be produced within the aquifer itself but are due to fluid admixture from other (deeper) formations.