A dataset of global zinc-bearing mineral deposits has been developed that complements previous such datasets (Franklin et al., 2005; Meinert et al., 2005; Mosier et al., 2009a,b; Taylor et al. 2009). The new dataset provides information on name, location, type, metal endowment, host rocks, associated igneous rocks, regional and proximal alteration assemblages (including, where possible, spatial and temporal zonation), Fe-S-O mineralogy, the presence of sulfate minerals, and sulfur and lead isotope data. In particular, unlike previous datasets, the age information provides the uncertainties of age determinations along with information on the assumptions and analytical methods used to determine the age. The dataset is meant to be used in conjunction with previous datasets and will be updated. Analysis of trends and relationships within the datasets are ongoing and will be published separately.

<div>Lead isotopic data implies that Th and U were fractionated from one another in Earth's early history, however, the origin of this fractionation is poorly understood. We report new <em>in-situ</em> Pb isotope data from orthoclase in 144 granites, sampled across the Archean Yilgarn Craton to characterize its Pb isotope variability and evolution. Granite Pb isotope compositions reveal three Pb sources, a mantle derived Pb reservoir and two crustal Pb reservoirs, distinguished by their implied source 232Th/238U (κPb). High-κPb granites reflect sources with high 232Th/238U (~4.7) and are largely co-located with Eoarchean–Paleoarchean crust. The Pb isotope compositions of most granites, and those of VHMS and gold ores, define a mixing array between a mantle Pb source and a Th-rich Eoarchean-Paleoarchean source. Pb isotope modelling indicates that the high-κPb source rocks experienced Th/U fractionation at ~3.3 Ga. As Th/U fractionation in the Yilgarn Craton must have occurred before Earth’s atmosphere was oxygenated, subaerial weathering cannot explain the apparent differences in their geochemical behavior. Instead, the high Th/U source reflects Eoarchean–Paleoarchean rocks that experienced prior high-temperature metamorphism, partial melting, and melt loss in the presence of a Th-sequestering mineral like monazite. Archean Pb isotope variability thus has its origins in open-system high-temperature metamorphic processes responsible for the differentiation and stabilization of Earth’s continental crust.</div> <b>Citation:</b> M.I.H. Hartnady, C.L. Kirkand, S.P. Johnson, R.H. Smithies, L.S. Doucet, D.R. Mole; <i>Origin of Archean Pb isotope variability through open-system Paleoarchean crustal anatexis</i>. Geology 2023; doi: https://doi.org/10.1130/G51507.1

Estimating the relative contributions of bedrock geology, mineralisation and anthropogenic contamination to the chemistry of samples collected at the Earth’s surface is critical in research and application fields as diverse as environmental impact studies and regional mineral exploration programs. The element lead (Pb) is a particularly useful tracer in this context, representing a toxin of environmental concern and associated with many other anthropogenic contaminants (e.g. mine wastes, waters, paints, aerosols), as well as with mineralisation. Although Pb concentration data are frequently collected in geochemical studies, isotopic analysis offers an important advantage, allowing discrimination between different sources of Pb. The Pb isotopic composition of regolith is likely to reflect contributions from underlying rock (including Pb-rich mineralisation), wind-blown dust and possibly anthropogenic sources (industry, transport, agriculture, residential, waste handling). Regolith samples collected at different depths may show distinct compositions; bedrock isotopic signatures are expected to dominate in deeper soils, whilst airborne dust and anthropogenic signatures are more important at the surface. Pb isotope ratios in the continental crust show large variations, which will be transferred to the regolith, providing a potentially unique bedrock signal that is easily measured. This research program examines if soil Pb isotope mapping can identify the underlying geology and metallogenic provinces, if different sampling and analytical approaches produce very different results, and how anthropogenic signals vary across the continent. Here, we present our results for the Northern Territory, where single regolith samples from many (not all) catchments define apparently consistent isotopic domains that can be interpreted in relation to the underlying geology (crystalline basement, basins) and mineral deposits. <b>Citation:</b> Desem, C.U., Maas, R., Woodhead, J., Carr, G. and de Caritat P., 2020. Towards a Pb isotope regolith map of the Australian continent: a Northern Territory perspective. In: Czarnota, K., Roach, I., Abbott, S., Haynes, M., Kositcin, N., Ray, A. and Slatter, E. (eds.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, 1–4.