Isotopic Atlas of Australia - An Update for AESC 2023

At the 2021 AESC (Australian Earth Sciences Convention), Geoscience Australia (GA) introduced a continental-scale Isotopic Atlas of Australia (Fraser et al., 2020) through an interactive poster display (Fraser et al., 2021). In the two years since, progress on this Isotopic Atlas has continued and expanded datasets are now publicly available and downloadable via Geoscience Australia’s Exploring for the Future (EFTF) Geochronology and Isotopes Data Portal.

This poster provides example maps produced from the compiled data of multiple geochronology and isotopic tracer datasets, now available in the Geochronology and Isotopes Data Portal. Available data include Sm–Nd model ages of magmatic rocks (Champion et al., 2013); Lu–Hf isotopes from zircon and associated O-isotope data (Waltenberg et al., 2023); Pb–Pb isotopes from ore-related minerals such as galena and pyrite (Huston et al., 2019); Rb–Sr stable isotopes from surface regolith (de Caritat et al., 2022, 2023); U–Pb interpreted ages of magmatic, metamorphic and sedimentary rocks (Jones et al., 2018); and K–Ar, Ar–Ar, Re–Os, Rb–Sr and fission-track interpreted ages from minerals and whole rocks.

Significant recent additions to the datasets include geochronology compilations for Victoria (Waltenberg et al., 2021) and Tasmania (Jones et al., 2022) and full geochronology analytical data tables for GA’s SHRIMP (Sensitive High Resolution Ion Micro Probe) U–Pb results. The online data portal provides tools for visualizing data in commonly-used diagrammatic formats (e.g. Time-Space style plots for geochronology, isotope evolution diagrams for Nd and Hf data). Data are also available for download in a range of formats (CSV, JSON, KML, Shapefile) to allow manipulation and visualization offline for specific purposes.

Work is ongoing to improve the coverage of legacy interpreted ages geochronology data, to include geochronology analytical data tables for both ID-TIMS and LA-ICP-MS data, and to update the Sm-Nd and Pb-Pb in ores coverages with new data. New work is in progress to develop a Pb-Pb isotopic coverage from representative ‘basement’ rocks (Liebmann et al., 2022) and to expand the coverage of oxygen and Lu-Hf isotopes from zircon, with a current focus in south-eastern Australia (Mole et al., 2022).

This Isotopic Atlas of Australia provides a convenient visual overview of age and isotopic patterns reflecting geological processes that have led to the current configuration of the Australian continent, including progressive development of continental crust from the mantle. These datasets and maps unlock the collective value of several decades of geochronological and isotopic studies conducted across Australia, and provide an important complement to other geological maps and geophysical images—in particular, by adding a time dimension to 2D and 3D maps and models. Abstract/Poster submitted and presented at 2023 Australian Earth Science Convention (AESC), Perth WA (https://2023.aegc.com.au/)