<div>We present the first national-scale lead (Pb) isotope maps of Australia based on surface regolith for five isotope ratios, ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb, ²⁰⁸Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁶Pb, and ²⁰⁸Pb/²⁰⁶Pb, determined by single collector Sector Field-Inductively Coupled Plasma-Mass Spectrometry after an Ammonium Acetate leach followed by Aqua Regia digestion. The dataset is underpinned principally by the National Geochemical Survey of Australia (NGSA) archived floodplain sediment samples. We analysed 1219 ‘top coarse’ (0-10 cm depth, &lt;2 mm grain size) samples, collected near the outlet of 1098 large catchments covering 5.647 million km2 (~75% of Australia). This paper focusses on the Aqua Regia dataset. The samples consist of mixtures of the dominant soils and rocks weathering in their respective catchments (and possibly those upstream) and are therefore assumed to form a reasonable representation of the average isotopic signature of those catchments. This assumption was tested in one of the NGSA catchments, within which 12 similar ‘top coarse’ samples were also taken; results show that the Pb isotope ratios of the NGSA catchment outlet sediment sample are close to the average of the 12 sub-catchment, upstream samples. National minimum, median and maximum values reported for ²⁰⁶Pb/²⁰⁴Pb were 15.558, 18.844, 30.635; for ²⁰⁷Pb/²⁰⁴Pb 14.358, 15.687, 18.012; for ²⁰⁸Pb/²⁰⁴Pb 33.558, 38.989, 48.873; for ²⁰⁷Pb/²⁰⁶Pb 0.5880, 0.8318, 0.9847; and for ²⁰⁸Pb/²⁰⁶Pb 1.4149, 2.0665, 2.3002, respectively. The new dataset was compared with published bedrock and ore Pb isotope data, and was found to dependably represent crustal elements of various ages from Archean to Phanerozoic. This suggests that floodplain sediment samples are a suitable proxy for basement and basin geology at this scale, despite various degrees of transport, mixing, and weathering experienced in the regolith environment, locally over protracted periods of time. An example of atmospheric Pb contamination around Port Pirie, South Australia, where a Pb smelter has operated since the 1890s, is shown to illustrate potential environmental applications of this new dataset. Other applications may include elucidating detail of Australian crustal evolution and mineralisation-related investigations.&nbsp;</div> <b>Citation:</b> Desem, C. U., de Caritat, P., Woodhead, J., Maas, R., and Carr, G.: A regolith lead isoscape of Australia, <o>Earth Syst. Sci. Data</i>, 16, 1383–1393, https://doi.org/10.5194/essd-16-1383-2024, 2024.

Background Wetlands provide a wide range of ecosystem services including improving water quality, carbon sequestration, as well as providing habitat for fish, amphibians, reptiles and birds. Managing wetlands in Australia is challenging due to competing pressures for water availability and highly variable climatic settings. The Wetlands Insight Tool (Ramsar Wetlands) has been developed to provide catchment managers, environmental water holders, andwetlands scientists a consistent historical baseline of wetlands dynamics from 1987 onwards. The Wetlands Insight Tool (Ramsar Wetlands) is available online through the DEA Mapswebsite. The Ramsar Wetlands of Australia Dataset is available under a Creative Commons Attribution 3.0 Australia Licence. We created individual wetland polygons from the multipart Ramsar polygons in the dataset. The 6 Australian Ramsar Sites in external territories are excluded as they are outside of Australia’s satellite data footprint. What this product offers The Wetlands Insight Tool (Ramsar Wetlands) summarises how the amount of water, green vegetation, dry vegetation and bare soil varies over time within eachwetland boundary.It provides the user with the ability to compare how the wetland is behaving now with how it has behaved in the past. This allows users to identify how changes in water availability have affected the wetland.It achieves this bypresentinga combined view of Water Observations from Space (DEA Water Observations), Tasseled Cap Wetness (DEA Wetness Percentiles) and Fractional Cover (DEA Fractional Cover) measurements from the Landsat series of satellites, summarised as a stacked line plot to show how that wetlandhas changed over time.