Patrice de Caritat

Geoscience Australia

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...

The National Geochemical Survey of Australia (NGSA) is Australia’s only internally consistent, continental-scale geochemical atlas and dataset. The present report presents additional mineralogical data acquired as part of the Heavy Mineral Map of Australia (HMMA) project on the NGSA samples, covering ~81% of Australia. The HMMA project, a collabora...

The Heavy Mineral Map of Australia (HMMA) is the world’s first project aiming to define acontinental heavy mineral baseline. It utilises a novel sample processing workflow andautomated mineralogy techniques to rapidly generate and analyse mineralogical data from1315 archived samples of catchment outlet sediments collected from 1186 catchmentsacross...

A novel method of estimating the silica (SiO 2 ) and loss-on-ignition (LOI) concentrations for the North American Soil Geochemical Landscapes (NASGL) project datasets is proposed. Combining the precision of the geochemical determinations with the completeness of the mineralogical NASGL data, we suggest a ‘reverse normative’ or inversion approach to...

The airborne fraction of soil (dust) is both ubiquitous in nature and contains localised biological and chemical signatures, making it a potential medium for forensic intelligence. Metabarcoding of dust can yield biological communities unique to the site of interest, similarly, geochemical analyses can uncover elements and minerals within dust that...

A novel method of estimating the silica (SiO2) and loss-on-ignition (LOI) concentrations for the North American Soil Geochemical Landscapes (NASGL) project datasets is proposed. Combining the precision of the geochemical determinations with the completeness of the mineralogical NASGL data, we suggest a ‘reverse normative’ or inversion approach to c...

With a higher demand for lithium (Li), a better understanding of its concentration and spatial distribution is important to delineate potential anomalous areas. This study uses a digital soil mapping framework to combine data from recent geochemical surveys and environmental covariates that affect soil formation to predict and map aqua-regia-extrac...

Heavy mineral techniques have been successfully used as exploration vectors to ore deposits around the world. However, heavy mineral exploration case studies and pre-competitive datasets relevant to Australian conditions are relatively limited. The Heavy Mineral Map of Australia (HMMA) project, part of Geoscience Australia's Exploring for the Futur...

Strontium isotopes (87Sr/86Sr) are useful to trace processes in the Earth sciences as well as in forensic, archaeological, palaeontological, and ecological sciences. As very few large-scale Sr isoscapes exist in Australia, we have identified an opportunity to determine 87Sr/86Sr ratios on archived fluvial sediment samples from the low-density Natio...

Environmental DNA (eDNA), elemental and mineralogical analyses of soil have been shown to be specific to their source material, prompting consideration of using the airborne fraction of soil (dust) for forensic intelligence work. Dust is ubiquitous in the environment and is easily transferred to items belonging to a person of interest, making dust...

Strontium isotopes (87Sr / 86Sr) are useful in the Earth sciences as well as in forensic, archaeological, palaeontological, and ecological sciences. As very few large-scale Sr isoscapes exist in Australia, we have identified an opportunity to determine 87Sr / 86Sr ratios on archive fluvial sediment samples from the low-density National Geochemical...

With a higher demand for lithium (Li), a better understanding of its concentration and spatial distribution is important to delineate potential anomalous areas. This study uses a digital soil mapping framework to combine data from recent geochemical surveys and environmental covariates to predict and map Li content across the 7.6 million km2 area o...

The National Geochemical Survey of Australia (NGSA) is Australia's first national-scale geochemical survey. It was delivered to the public on 30 June 2011, after almost five years of stakeholder engagement, strategic planning, sample collection, preparation and analysis, quality assurance/quality control, and preliminary data analytics. The project...

Alluvial sediments have long been used in geochemical surveys as their compositions are assumed to be representative of areas upstream. Overbank and floodplain sediments, in particular, are increasingly used for regional to continental-scale geochemical mapping. However, during downstream transport, sediments from heterogeneous source regions are c...

The values and distribution patterns of the strontium (Sr) isotope ratio 87 Sr/ 86 Sr in Earth surface materials are of use in the geological, environmental, and social sciences. Ultimately, the 87 Sr/ 86 Sr ratios of soils and everything that lives in and on them are inherited from the rocks that are the parent materials of the soil's components....

We describe a vision for a national-scale heavy mineral (HM) map generated through automated mineralogical identification and quantification of HMs contained in floodplain sediments from large catchments covering most of Australia. The composition of the sediments reflects the dominant rock types in each catchment, with the generally resistant HMs...

We describe a vision for a national-scale heavy mineral (HM) map generated through automated mineralogical identification and quantification of HMs contained in floodplain sediments from large catchments covering most of Australia. The composition of the sediments reflects the dominant rock types in each catchment, with the generally resistant HMs...

The values and distribution patterns of the strontium (Sr) isotope ratio 87Sr / 86Sr in Earth surface materials is of use in the geological, environmental and social sciences. Ultimately, the 87Sr / 86Sr ratio of soil and everything that lives in and on it is inherited from the rock that is its parent material. In Australia, there are few large-sca...

Mineral deposits are metal enrichment anomalies, occurring as local manifestations of the interplay between various geological processes that operate at a wide range of temporal and spatial scales. Mineral prospectivity maps are generated by integrating several proxy maps that represent critical geological processes in a mineral system conceptual m...

Soil is a ubiquitous material at the Earth's surface with potential to be a useful evidence class in forensic and intelligence applications. Compositional data from a soil survey over North Canberra, Australian Capital Territory, are used to develop and test an empirical soil provenancing method. Mineralogical data from Fourier Transform InfraRed s...

The Australian Capital Territory Geochemical Urban Mapping (ACTGUM) project, a collaboration between the National Centre for Forensic Studies at the University of Canberra, Geoscience Australia (GA) and the Australian Federal Police, has been established as part of a research program for undergraduate and postgraduate science students. The ACTGUM p...

Compositional data from a soil survey over North Canberra, Australian Capital Territory, are used to develop and test an empirical soil provenancing method. Mineralogical data from Fourier transform infrared spectroscopy (FTIR) and magnetic susceptibility (MS), and geochemical data from X‐ray fluorescence (XRF; for total major oxides) and inductive...

Heavy minerals (HMs) are minerals with a specific gravity greater than 2.9 g/cm3. They are commonly highly resistant to physical and chemical weathering, and therefore persist in sediments as lasting indicators of the (former) presence of the rocks they formed in. The presence/absence of certain HMs, their associations with other HMs, their concent...

Plutonium (Pu) interactions in the environment are highly complex. Site-specific variables play an integral role in determining the chemical and physical form of Pu, and its migration, bioavailability, and immobility. This paper aims to identify the key variables that can be used to highlight regions of radioecological sensitivity and guide remedia...

Exploring for the Future (EFTF) is a four-year (2016-20) geoscience data and information acquisition program that aims to better understand on a regional scale the potential mineral, energy and groundwater resources concealed under cover in northern Australia and parts of South Australia. Hydrogeochemical surveys utilise groundwater as a passive sa...

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 trac...

With the increasing need to extend mineral exploration undercover, new approaches are required to better constrain concealed geology, thereby reducing exploration risk and search space. Hydrogeochemistry is an under-utilised tool that can identify subsurface geology and buried mineral system components, while also providing valuable insights into e...

Soil is a common evidence type used in forensic and intelligence operations. Where soil composition databases are lacking or inadequate, we propose to use publicly available soil attribute rasters to reduce forensic search areas. Soil attribute rasters, which have recently become widely available at high spatial resolutions, typically three arc‐sec...

We collected 38 groundwater and two surface-water samples in the semi-arid Lake Woods region of the Northern Territory to better understand the hydrogeochemistry of this system, which straddles the Wiso, Tennant Creek and Georgina geological regions. Lake Woods is presently a losing waterbody feeding the underlying groundwater system. The main aqui...

Global-scale, or continental-scale, geochemical surveys cover millions of square kilometers of the Earth’s surface generally at a very low sample density (1 site per 1,000 to 10,000 km2). Geochemical patterns produced from these low-density surveys reflect processes that act at the broad scale of sampling. These processes are related to many factor...

Exploring for the Future (EFTF) is a four-year (2016-20) geoscience data and information acquisition program that aims to better understand on a regional scale the potential mineral, energy and groundwater resources concealed under cover in northern Australia and parts of South Australia. Hydrogeochemical surveys utilise groundwater as a passive sa...

Prediction of true classes of surficial and deep earth materials using multivariate spatial data is a common challenge for geoscience modelers. Most geological processes leave a footprint that can be explored by geochemical data analysis. These footprints are normally complex statistical and spatial patterns buried deep in the high-dimensional comp...

Understanding the distribution of surface geochemistry at broad scales is a significant challenge. This is due to the sparse nature of point data observations and the complex characteristics of the 'critical zone' (near surface zone between tree tops and groundwater aquifers). Here is where the biogeochemical processes that alter the substrate occu...

Understanding the distribution of surface geochemistry at broad scales is a significant challenge. This is due to the sparse nature of point data observations and the complex characteristics of the critical zone, the near surface zone between tree tops and groundwater aquifers. This is where the biogeochemical processes that alter the substrate occ...

The Australian Federal Police (AFP) has been conducting comparative soil examinations for several years for the comparison of recovered soil samples to known soil samples. The comparative examination process implemented by the AFP uses the instrumentation common to trace evidence laboratories and does not require extensive soil knowledge to success...

The Australian Federal Police (AFP) has been conducting comparative soil examinations for several years for the comparison of recovered soil samples to known soil samples. The comparative examination process implemented by the AFP uses the instrumentation common to trace evidence laboratories and does not require extensive soil knowledge to success...

This report entails the procedures used for measuring soil and powder samples using Bruker Vertex 70 and Bruker Vertex 80 FTIRs with a MCT detector attached to a Bruker A562 integrating hemisphere and ASD FieldSpec3 and FieldSpec4 spectroradiometers. The measurements were collected between June 2013 and June 2016 using the two FTIR spectrometers a...

The multi-element aqua regia National Geochemical Survey of Australia (NGSA) database is used to demonstrate an improved method for quantifying the degree of geochemical similarity (DOGS2) between soil samples. The improvements introduced here address issues relating to compositional data (closure, relative scale). After removing the elements with...

Several mineral prospectivity studies that have been undertaken recently using the NGSA dataset are reviewed.

The National Geochemical Survey of Australia (NGSA) provides an internally consistent, state-of-the-art, continental-scale geochemical dataset that can be used to assess areas of Australia more elevated in commodity metals and/or pathfinder elements than others. But do regions elevated in such elements correspond to known mineralized provinces, and...

This report entails the procedures used for quality control checking of spectral measurements of soils and powdered materials measured with the Bruker Vertex FTIR instruments with an integrating hemisphere and an ASD FieldSpec spectroradiometers. A component of data management is the curation and storage of spectral data along with its metadata and...

The GEMAS (geochemical mapping of agricultural soil) project collected 2108 Ap horizon soil samples from regularly ploughed fields in 33 European countries, covering 5.6 million km2. The <2 mm fraction of these samples was analysed for 53 elements by ICP-MS and ICP-AES, following a HNO3/HCl/H2O (modified aqua regia) digestion. Results are used here...

Executive Summary This hydrogeochemical atlas for South Australia builds on the accompanying notes to the revised hydrogeochemical data from the SA_Geodata groundwater dataset. The dataset is available online (Gray and Bardwell, 2016a; http://doi.org/10.4225/08/5756B3BF09204) and is part of the ‘Continental Scale Hydrogeochemistry’ initiative. The...

During the last 10–20 years, Geological Surveys around the world have undertaken a major effort towards delivering fully harmonised and tightly quality controlled low-density multi-element soil geochemical maps and datasets of vast regions including up to whole continents. Concentrations of between 45 and 60 elements commonly have been determined i...

The Proposal for the establishment of the International Centre on Global-Scale Geochemistry (ICGG) in Langfang, P.R. Chi- na, under the auspices of UNESCO as a Category II Centre, was ap- proved at the 37th session of UNESCO in Paris on the 13th of Novem- ber 2013. Following its formal approval by the Chinese Government, the agreement between UNESC...

Multi-element geochemical surveys of rocks, soils, stream/lake/floodplain sediments, and regolith are carried out by governments and mineral exploration companies at continental (0.5-50 million km 2), regional (500-500,000 km 2) and local (0.5-500 km 2) scales. The chemistry of these materials is defined by their primary mineral assemblages and the...

The results of a pilot study into the application of an unsupervised clustering approach to the analysis of catchment-based National Geochemical Survey of Australia (NGSA) geochemical data combined with geophysical and geological data across northern Australia are documented. NGSA Mobile Metal Ion® (MMI) element concentrations and first and second...

A new method for detecting and quantifying diffuse contamination at the continental to regional scale is based on the analysis of cumulative distribution functions (CDFs). It uses cumulative probability (CP) plots for spatially representative data sets, preferably containing >1000 determinations. Simulations demonstrate how different types of conta...

poster in SSS3.5 - Geochemical mapping at all scales: evidence from soil, sediment, water and plants

This comment highlights a whole series of datasets on thallium concentrations in the environment that were overlooked in the recent review by Karbowska, Environmental Monitoring and Assessment, 188, 640, 2016 in this journal. Geochemical surveys carried out over the last few decades all over the world at various scales and using different sampling...

The log ratio methodology converts compositional data, such as concentrations of chemical elements in a rock, from their original Aitchison geometry to interpretable real orthonormal coordinates, thereby allowing meaningful statistical processing and visualization. However, it must be taken into account that the original concentrations can be flawe...

Multi-element near-surface geochemistry from the National Geochemical Survey of Australia has been evaluated in the context of mapping the exposed to deeply buried major crustal blocks of the Australian continent. The major crustal blocks, interpreted from geophysical and geological data, reflect distinct tectonic domains comprised of early Archean...

Chlorine and bromine play crucial roles in atmospheric element cycles and are important environmental tracers in catchment investigations, so understanding their distribution at the Earth's near-surface is imperative for deciphering their behaviour. This study presents the first continental-scale analysis of Cl− and Br− concentrations of wet deposi...

Understanding the character of Australia's extensive regolith cover is crucial to the continuing success of mineral exploration. We hypothesise that the regolith contains geochemical fingerprints of processes related to the development and preservation of mineral systems at a range of scales. We test this hypothesis by analysing the composition of...

During the National Geochemical Survey of Australia over 1300 top (0–10 cm depth) and bottom (~ 60–80 cm depth) sediment samples (including ~ 10% field duplicates) were collected from the outlet of 1186 catchments covering 81% of the continent at an average sample density of 1 site/5200 km². The < 2 mm fraction of these samples was analysed for 59...

Although the use of soil evidence in forensic casework has a long history it has often been only on a simple one-by-one comparison basis and/or relied heavily on local heuristic knowledge. For forensic intelligence gathering the spatial distribution of soil parameters needs to be documented, understood and modelled to provide continuous spatial cov...