Data gathered in the field during the sample collection phase of the National Geochemical Survey of Australia (NGSA) has been used to compile the Preliminary Soil pH map of Australia. The map, which was completed in late 2009, offers a first-order estimate of where acid or alkaline soil conditions are likely to be expected. It provides fundamental datasets that can be used for mineral exploration and resource potential evaluation, environmental monitoring, landuse policy development, and geomedical studies into the health of humans, animals and plants.

The Northern Australian Development Committee nominated the region of the Ord and Victoria rivers to be surveyed by the Northern Australian Regional Survey, when the Barkly Region had been completed. The immediate objectives of the Survey are "to accurately record the nature of the country, to establish a sound basis upon which the production possibilities of the Region may be appraised and to make general recommendations concerning development and further investigations." It was decided that the region should include the Army Four Mile Map Sheets of Delamere, Victoria River Downs, Wave Hill, Birrundudu, Limbunya, Waterloo, Auvergne, Port Keats, Medusa Banks, Cambridge Gulf, Lissadell, Dixon Range, and Gordon Downs, and that the field work would be commenced during the 1949 dry season. The techniques and methods used to complete this survey work are noted. The stratigraphy, pedology, and economic geology of the area are described in some detail.

Introduction Low-density geochemical surveys provide a cost-effective means to assess the composition of near-surface materials over large areas. Many countries in the world have already compiled geochemical atlases based on such data. These have been used for a number of applications, including: - establish baselines from which future changes can be measured - design geologically sensible targets for remediation of contaminated sites - support decision-making regarding appropriate land-use - explore for natural resources - study links between geology and plant/animal health (geohealth) A first pilot project was initiated to help establish sampling and analytical protocols relevant to Australian landscapes and climates. The Riverina region was chosen for this study because of its crucial economic, environmental and societal importance within the Murray-Darling basin. The region is a prime agricultural area, is bordered to the south by the Victorian goldfields, and is home to 11% of the Australian population. Results of this study are presented here. Methods Using a hydrological analysis, 142 sites near the outlets of large catchments were selected within the 123,000 km2 survey area (1 site per 866 km2 on average). At each site, two 10-cm thick overbank sediment samples were taken, one at the surface ('top overbank sediment', TOS) and the other between 60 and 90 cm depth (`bottom overbank sediment', BOS). These were described, dried, sieved (<180 m) and analysed chemically for 62 elements. Exploratory data analysis was undertaken and geochemical maps (various styles are shown here) were prepared. Results and discussion The geology of the area is dominated by Cainozoic sediments found in low-relief plains over the vast majority of the Riverina. The eastern and southern fringes of the area form higher relief landforms developed on outcropping or subcropping Palaeozoic sedimentary, mafic and felsic volcanic and felsic intrusive rocks. The geochemical results of the survey are independently corroborated by the good match between the distributions of K, U and Th concentrations in TOS and airborne gamma-ray maps. The distribution of Ca in BOS indicates generally higher concentrations in the northern part of the study area, which is also reflected in higher soil pH values there. Such data have implications for soil fertility and management in agricultural areas. In terms of applications to mineral exploration, dispersion trains of typical pathfinder elements for gold mineralisation, like As and Sb are clearly documented by the smoothly decreasing concentrations from south (near the Victorian goldfields) to north (over sediments from the Murray basin). Chromium is an element that can be associated with ill-health in animals and humans when present over certain levels. There is a smooth increase in Cr concentration from north to south, and the two sites with the highest values can be correlated with a ridge of Cambrian mafic volcanics. High total Cr concentrations in the Riverina are unlikely, however, to lead to serious health problems as only a very small proportion of Cr will be bioavailable. Conversely, some elements can be present at concentrations that are too low for optimum plant growth, such as potentially Mo. The distribution map for this element shows a general decrease from south to north. Given its lower bioavailability in acid soils, Mo is likely to be deficient in the south of the region, despite higher total concentrations here. Farmers report the necessity to use Mo-enriched fertilisers in this area. Conclusions Low-density geochemical surveys can be conducted in Australia using common regolith sampling media. They provide a cost-effective, internally consistent dataset that can be used by to support a variety of critical economic, environmental and societal decisions.

As a results of representations made to the Bureau of Mineral Resources by the Australian Aluminium Production Commission during 1948 a brief examination was made in July, 1949, of the area known as Sogeri Plateau which is situated some 24 miles east-north-east of Port Moresby. The object of the inspection was to determine whether any bauxitic laterite was present on the plateau and if so to obtain samples for chemical determination of alumina soluble in caustic soda solution, that is, alumina extractable by the Bayer process. Three car traverses of the area were made - one along the Sogeri-Uberi road, one along the Sogeri-Subitana road and one along the Sogeri-Eilogo road. Two grab samples were collected and sent for analysis. The findings of the examination of the area and the results of the chemical analyses are described in this report.

<div>The ubiquitous nature of dust, along with localised chemical and biological signatures, makes it an ideal medium for provenance determination in a forensic context. Metabarcoding of dust can yield biological communities unique to the site of interest, similarly, geochemical and mineralogical analyses can uncover elements and minerals within dust than can be matched to a geographic location. Combining these analyses presents multiple lines of evidence as to the origin of collected dust samples. In this work, we investigated whether the time an item spent at a site collecting dust influenced the ability to assign provenance. We then integrated dust metabarcoding of bacterial and fungal communities into a framework amenable to forensic casework, (i.e., using calibrated log-likelihood ratios to predict the origin of dust samples) and assessed whether current soil metabarcoding databases could be utilised to predict dust origin. Furthermore, we tested whether both metabarcoding and geochemical/mineralogical analyses could be conducted on a single sample for situations where sampling is limited. We found both analyses could generate results capable of separating sites from a single swabbed sample and that the duration of time to accumulate dust did not impact site separation. We did find significant variation within sites at different sampling time periods, showing that bacterial and fungal community profiles vary over time and space – but not to the extent that they are non-discriminatory. We successfully modelled soil and dust samples for both bacterial and fungal diversity, developing calibrated log-likelihood ratio plots and used these to predict provenance for dust samples. We found that the temporal variation in community composition influenced our ability to predict dust provenance and recommend reference samples be collected as close to the sampling time as possible. Thus, our framework showed soil metabarcoding databases are capable of being used to predict dust provenance but the temporal variation in metabarcoded communities will need to be addressed to improve provenance estimates.&nbsp;</div> <b>Citation:</b> Nicole R. Foster, Duncan Taylor, Jurian Hoogewerff, Michael G. Aberle, Patrice de Caritat, Paul Roffey, Robert Edwards, Arif Malik, Michelle Waycott and Jennifer M. Young, The secret hidden in dust: Uncovering the potential to use biological and chemical properties of the airborne soil fraction to assign provenance and integrating this into forensic casework, <i>Forensic Science International: Genetics,</i> (2023) doi:https://doi.org/10.1016/j.fsigen.2023.102931

A fundamental component of soils is its mineralogy which is a key driver/indicator of important soil properties/processes such as soil pH (acidity), metal availability (e.g. Al, K, Fe, Si, Ca, Mg) and water content/permeability/runoff. However, soil mineralogy is not routinely measured as part of current soil mapping programs at the paddock-, catchment- or continental-scales mainly because currently deployed measurement technologies are not able to deliver soil mineralogy directly, though remote radiometric and microwave sensing technologies do provide useful soil information. In contrast, mineralogy is now being efficiently delivered to the Australian minerals exploration industry through a new generation of field, airborne and spaceborne hyperspectral technologies (www.hyvista.com; nvcl.csiro.au/). This mineral information includes two of the three major soil mineral components, namely: clays (e.g. kaolinite, illite, smectite); and iron/aluminium oxyhydroxides (e.g. hematite. goethite, gibbsite), with specific information being delivered on their composition, abundances and physicochemistries (disorder and chemistry). The third dominant soil mineral component, quartz, is also spectrally measurable but has diagnostic features at wavelengths longer than current "operational" hyperspectral systems. These hyperspectral technologies thus provide an excellent opportunity to transfer mineral mapping capabilities being developed for the minerals industry into the soil mapping application, especially for establishing baseline inventories of soil mineral composition and providing a possible mechanism for quantitative monitoring of change in soil properties related to its mineralogy (e.g. pH, soil loss, water effects, metal activities and possibly soil carbon and salinity). This opportunity is explored using results from a collaborative geological remote sensing project between the CSIRO, the Geological Survey of Queensland and Geoscience Australia (www.em.csiro.au/NGMM, www.nrw.qld.gov.au/science/geoscience/projects/hyperspectral.html) which involves the collection and processing of 25,000 km2 of airborne HyMap imagery (~300 flight-lines at 5m pixel resolution and totalling >1 Terabyte of raw data) from across Queensland, including areas covered by airborne radiometrics and published geology at 1:100 000 scale around the Mount Isa region. The processed hyperspectral data show that lateritic materials in the Tick Hill area comprise relatively abundant iron oxides and kaolinite (poorly ordered) whereas the radiometrics shows these areas as being relatively high Th and U counts. This kaolinite is presumably developed in response to more acid conditions and/or better (downward percolating) drainage. The hyperspectral data also maps extensive areas of Al-smectite (montmorillonite) associated with the weathering of carbonate (calcite and dolomite) parent rocks or as "pedogenic" occurrences in alluvium/colluvium, with the latter sometimes associated with abundant opaline silica (also mapped using the hyperspectral data). These Al-rich smectites are formed in more alkaline conditions where there is sufficient Ca or Mg and water at the near surface and typically show in the radiometric as being poor in K and Th. Muscovite (water-poor, K-bearing white mica) is mapped over exposed parent rocks whereas illite (water-rich, K-bearing white mica) is typically mapped in weathered materials, including many soils and dried lake beds where there is sufficient available K. The radiometric data typically shows these areas as being K-rich. Note that the accuracy of the hyperspectral clay mineral maps was also validated by field sampling and associated laboratory spectral and X-Ray diffraction analyses.

Soils are one of the key factors which limit human settlement in Australia. Few Australian soils are of good quality - most are naturally infertile. This map shows the extent of soil limitations across the country. In order to overcome problems associated with the many classifications in existence, this map classes soils according to limitations of use - in particular chemical and physical limitations. Altogether, four primary groupings are shown and these are further divided into a total of 29 mapping units. A detailed table relates these units to traditionally classified soil profiles and landforms. Product Specifications: Coverage: Australia Currency: 1976-77 Coordinates: Geographical Datum: AGD66 (GDA94 compliant at this scale) Projection: Simple Conic on two standard parallels 18S and 36S Medium: Paper, flat and folded copies

The National Geochemical Survey of Australia (NGSA) provides the first national coverage of multi-element chemistry at a continental scale. The NGSA data is an important complement to other national-scale geological and geophysical datasets, particularly the Radiometric Map of Australia. The Radiometric Map of Australia shows potassium (K) measured directly from gamma-rays emitted when 40K decays to argon (40Ar), whereas thorium (Th) and uranium (U) do not emit gamma-rays. Instead, their abundances are inferred indirectly by measuring gamma-ray emissions associated with parent radionuclides (thallium-208 for Th, and bismuth-214 for U) within their radioactive decay chains. Airborne-derived grids provide a continuous prediction of these radioelements across the Australian landscape. In contrast, the NGSA data provide a series of precise single point geochemical measurements of surface (0-10 cm) and near-surface (~60-80 cm depth) unconsolidated catchment outlet sediments.

Following the drilling of a shallow natural CO₂ reservoir at the Qinghai research site, west of Haidong, China, it was discovered that CO₂ was continuously leaking from the wellbore due to well-failure. The site has become a useful research facility in China for studying CO₂ leakage and monitoring technologies for application to geological storage sites of CO₂. During an eight day period in 2014, soil gas and soil flux surveys were conducted to characterise the distribution, magnitude and likely source of the leaking CO₂ . Two different sampling patterns were utilised during soil flux surveys. A regular sampling grid was used to spatially map out the two high-flux zones which were located 20–50 m away from the wellhead. An irregular sampling grid, with higher sampling density in the high-flux zones, allowed for more accurate mapping of the leak distribution and estimation of total field emission rate using cubic interpolation. The total CO₂ emission rate for the site was estimated at 649-1015 kgCO₂/d and there appeared to be some degree of spatial correlation between observed CO₂ fluxes and elevated surface H₂O fluxes. Sixteen soil gas wells were installed across the field to test the real-time application of Romanak et al.’s (2012) process-based approach for soil gas measurements (using ratios of major soil gas components to identify the CO₂ source) using a portable multi-gas analyser. Results clearly identified CO₂ as being derived from one exogenous source, and are consistent with gas samples collected for laboratory analysis. Carbon-13 isotopes in the centre of each leak zone (−0.21‰ and −0.22‰) indicate the underlying CO₂ is likely sourced from the thermal decomposition of marine carbonates. Surface soil mineralisation (predominantly calcite) can be used to infer prior distribution of the CO₂ hotspots and as a consequence highlighted plume migration of 20m in 11 years. The broadening of the affected area beyond the wellbore at the Qinghai research site markedly increases the area that needs surveying at sufficient density to detect a leak. This challenges the role of soil gas and soil flux in a CCS monitoring and verification program for leak detection, suggesting that these techniques may be better applied for characterising the source and emission rate of a CO₂ leak, respectively. <b>Citation:</b> I.F. Schroder, H. Zhang, C. Zhang, A.J. Feitz, The role of soil flux and soil gas monitoring in the characterisation of a CO2 surface leak: A case study in Qinghai, China, International Journal of Greenhouse Gas Control, Volume 54, Part 1, 2016, Pages 84-95, ISSN 1750-5836, https://doi.org/10.1016/j.ijggc.2016.07.030.

Geoscience Australia and the CO2CRC have constructed a greenhouse gas controlled release facility at an experimental agricultural station maintained by CSIRO Plant Industry at Ginninderra, Canberra. The facility is designed to simulate surface emissions of CO2 (and other greenhouse gases) from the soil into the atmosphere. CO2 is injected into the soil is via a 120m long slotted HDPE pipe installed horizontally 2m underground. This is fitted with a straddle packer system to partition the well into six CO2 injection chambers with each chamber connected to its own CO2 injection line. CO2 was injected into 5 of the chambers during the first sub-surface release experiment (March - May 2012) and the total daily injection rate was 100 kg/d. A krypton tracer was injected into one of the 5 chambers at a rate of 10 mL/min. Monitoring methods trialled at the site include eddy covariance, atmospheric tomography using a wireless networked array of solar powered CO2 stations, soil flux, soil gas, frequency-domain electromagnetics (FDEM), soil community DNA analysis, and krypton tracer studies (soil gas and air). A summary of the findings will be presented. Paper presented at the 2012 CO2CRC Research Symposium, Sunshine Beach, 27-29 November 2012.