<div>Historically, isotopic data are collected at the individual sample level on local- to regional-scale features and are dispersed among decades of both published and unpublished individual academic literature, university theses and geological survey reports, in disparate formats and with widely varying levels of detail. Consequently, it has been difficult to visualise or interrogate the collective value of age and isotopic data at continental-scale. Geoscience Australia’s (GA) continental-scale Isotopic Atlas of Australia (Fraser et al., 2020), breaks this cycle of single-use science by compiling and integrating <strong>multiple radiometric age and isotopic tracer datasets</strong> and making them publicly accessible and useable through GA’s Exploring for the Future (EFTF) Portal.</div><div><br></div><div>The first iteration of a continental-scale Isotopic Atlas of Australia was introduced by Geoscience Australia at the 2019 SGGMP conference in Devonport, Tasmania, through a talk and poster display. In the three 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.&nbsp;</div>

This web service provides access to the Geoscience Australia (GA) ISOTOPE database containing compiled age and isotopic data from a range of published and unpublished (GA and non-GA) sources. The web service includes point layers (WFS, WMS, WMTS) with age and isotopic attribute information from the ISOTOPE database, and raster layers (WMS, WMTS, WCS) comprising the Isotopic Atlas grids which are interpolations of the point located age and isotope data in the ISOTOPE database.

The ISOTOPE database stores compiled age and isotopic data from a range of published and unpublished (GA and non-GA) sources. This internal database is only publicly accessible through the webservices given as links on this page. This data compilation includes sample and bibliographic links. The data structure currently supports summary ages (e.g., U-Pb and Ar/Ar) through the INTERPRETED_AGES tables, as well as extended system-specific tables for Sm-Nd, Pb-Pb, Lu-Hf and O- isotopes. The data structure is designed to be extensible to adapt to evolving requirements for the storage of isotopic data. ISOTOPE and the data holdings were initially developed as part of the Exploring for the Future (EFTF) program. During development of ISOTOPE, some key considerations in compiling and storing diverse, multi-purpose isotopic datasets were developed: 1) Improved sample characterisation and bibliographic links. Often, the usefulness of an isotopic dataset is limited by the metadata available for the parent sample. Better harvesting of fundamental sample data (and better integration with related national datasets such as Australian Geological Provinces and the Australian Stratigraphic Units Database) simplifies the process of filtering an isotopic data compilation using spatial, geological and bibliographic criteria, as well as facilitating ‘audits’ targeting missing isotopic data. 2) Generalised, extensible structures for isotopic data. The need for system-specific tables for isotopic analyses does not preclude the development of generalised data-structures that reflect universal relationships. GA has modelled relational tables linking system-specific Sessions, Analyses, and interpreted data-Groups, which has proven adequate for all of the Isotopic Atlas layers developed thus far. 3) Dual delivery of ‘derived’ isotopic data. In some systems, it is critical to capture the published data (i.e. isotopic measurements and derived values, as presented by the original author) and generate an additional set of derived values from the same measurements, calculated using a single set of reference parameters (e.g. decay constant, depleted-mantle values, etc.) that permit ‘normalised’ portrayal of the data compilation-wide. 4) Flexibility in data delivery mode. In radiogenic isotope geochronology (e.g. U-Pb, Ar-Ar), careful compilation and attribution of ‘interpreted ages’ can meet the needs of much of the user-base, even without an explicit link to the constituent analyses. In contrast, isotope geochemistry (especially microbeam-based methods such as Lu-Hf via laser ablation) is usually focused on the individual measurements, without which interpreted ‘sample-averages’ have limited value. Data delivery should reflect key differences of this kind.

<div>Lithospheric and crustal architecture — the framework of major tectonic blocks, terranes and their boundaries — represents a fundamental first-order control on major geological systems, including the location of world-class mineral camps. Traditionally, lithospheric and crustal architecture are constrained using predominantly geophysical methods. However, Champion and Cassidy (2007) pioneered the use of regional Sm–Nd isotopic data from felsic igneous rocks to produce isotopic contour maps of the Yilgarn Craton, demonstrating the effectiveness of ‘isotopic mapping’, and the potential to map ‘time-constrained’ crustal architecture. Mole et al. (2013) demonstrated the association between lithospheric architecture and mineral systems, highlighting the potential of isotopic mapping as a greenfield area selection tool. Additional work, using Lu-Hf isotopes (Mole et al., 2014), demonstrated that the technique could constrain a range of temporal events via ‘time-slice mapping’, explaining how Ni-Cu-PGE mineralized komatiite systems migrated with the evolving lithospheric boundary of the Yilgarn Craton from 2.9 to 2.7 Ga. Similar studies have since been conducted in West Africa (Parra-Avila et al., 2018), Tibet (Hou et al., 2015), and Canada (Bjorkman, 2017; Mole et al., 2021; 2022). This work continues in Geoscience Australia’s $225 million Exploring for the Future program (2016-present). Isotopic mapping, which forms an integral part of a combined geology-geophysics-geochemistry approach, is currently being applied across southeast Australia, covering the eastern Gawler Craton, Delamerian Orogen, and western Lachlan Orogen, encompassing more than 3 Gyrs of Earth history with demonstrable potential for large mineral systems.</div><div> <b>Reference(s):</b></div><div> Bjorkman, K.E., 2017. 4D crust-mantle evolution of the Western Superior Craton: Implications for Archean granite-greenstone petrogenesis and geodynamics. University of Western Australia, PhD Thesis, 134 pp.</div><div> Champion, D.C. and Cassidy, K.F., 2007. An overview of the Yilgarn Craton and its crustal evolution. In: F.P. Bierlein and C.M. Knox-Robinson (Editors), Proceedings of Geoconferences (WA) Inc. Kalgoorlie '07 Conference. Geoscience Australia Record 2007/14, Kalgoorlie, Western Australia, pp. 8-13.</div><div> Hou, Z., Duan, L., Lu, Y., Zheng, Y., Zhu, D., Yang, Z., Yang, Z., Wang, B., Pei, Y., Zhao, Z. and McCuaig, T.C., 2015. Lithospheric architecture of the Lhasa terrane and its control on ore deposits in the Himalayan-Tibetan orogen. Economic Geology, 110(6): 1541-1575.</div><div> Mole, D.R., Fiorentini, M.L., Cassidy, K.F., Kirkland, C.L., Thebaud, N., McCuaig, T.C., Doublier, M.P., Duuring, P., Romano, S.S., Maas, R., Belousova, E.A., Barnes, S.J. and Miller, J., 2013. Crustal evolution, intra-cratonic architecture and the metallogeny of an Archaean craton. Geological Society, London, Special Publications, 393: pp. 23-80.</div><div> Mole, D.R., Fiorentini, M.L., Thebaud, N., Cassidy, K.F., McCuaig, T.C., Kirkland, C.L., Romano, S.S., Doublier, M.P., Belousova, E.A., Barnes, S.J. and Miller, J., 2014. Archean komatiite volcanism controlled by the evolution of early continents. Proceedings of the National Academy of Sciences, 111(28): 10083-10088.</div><div> Mole, D.R., Thurston, P.C., Marsh, J.H., Stern, R.A., Ayer, J.A., Martin, L.A.J. and Lu, Y., 2021. The formation of Neoarchean continental crust in the south-east Superior Craton by two distinct geodynamic processes. Precambrian Research, 356: 106104.</div><div> Mole, D.R., Frieman, B.M., Thurston, P.C., Marsh, J.H., Jørgensen, T.R.C., Stern, R.A., Martin, L.A.J., Lu, Y.J. and Gibson, H.L., 2022. Crustal architecture of the south-east Superior Craton and controls on mineral systems. Ore Geology Reviews, 148: 105017.</div><div> Parra-Avila, L.A., Belousova, E., Fiorentini, M.L., Eglinger, A., Block, S. and Miller, J., 2018. Zircon Hf and O-isotope constraints on the evolution of the Paleoproterozoic Baoulé-Mossi domain of the southern West African Craton. Precambrian Research, 306: 174-188.</div><div> This Abstract was submitted/presented to the Target 2023 Conference 28 July (https://6ias.org/target2023/)