The National Geochemical Survey of Australia Patrice de

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The National Geochemical Survey of Australia Patrice de Caritat Geoscience Australia A collaborative project under National Geoscience Agreements with New South Wales Department of Primary Industries, Mineral Resources Tasmania, Geo. Science Victoria, Primary Industries and Resources South Australia, Geological Survey of Western Australia, Northern Territory Geological Survey, Geological Survey of Queensland Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

Outline of Presentation • • • Why geochemical surveys? Review of pilot projects Aims of NGSA Strategy of NGSA Results and preliminary interpretations Ø Total element concentrations Ø Weak digestion concentrations Ø Visible near-infrared spectroscopy Conclusions Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

Geochemical Surveys 101 What are geochemical surveys? • GS are the documentation of the chemical composition of the Earth’s surface: concentration values & patterns • Fundamental dataset • Nature of end-product depends on a number of strategic decisions: Ø Purpose (minex, environmental, land-use, etc. ) Ø Size of area to cover (strategic v tactical) Ø Sampling medium Ø Sampling density Ø Constraints: time, resources, history, etc Gd+Sm Ti Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011) Neutron Spectrometry Data Elphic et al. (1998, 2000)

Geochemical Surveys 101 • • Initially developed for mineral exploration (“geochemical prospecting”) Reconnaissance geochemical surveys started in the 1960’s (Nichol et al. , 1966) Gained widespread popularity in many parts of the world over ensuing decades Variety of applications: mineral exploration, environmental baseline, geohealth (e. g. , drinking water!), land rehabilitation, risk assessment, etc. Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

Selected Results from Pilot Projects Approx area Average sampling Curnamona: Number ofsites (km ) sampling density (1 site per X km ) Ø Broken Hill region; base metal, Cu-Au Curnamona 61, 915 199 311 Riverina: 122, 976 142 866 • Gawler 53, 636 48 1117 Ø Agriculture, Murray Basin; Au, base metal Thomson 209, 824 99 2119 • Gawler: Ø Arid, flat, aeolian influence; Olympic Dam Feoxide-Cu-Au-U, Au • Thomson: Ø Eromanga/GAB Basin cover; borders on Curnamona and Cobar (base metal, Cu, Au) districts • Pilot survey 2 2 Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

Selected Results from Pilot Projects Riverina: Th channel airborne radiometrics vs Th (ppm) in <180 um TOS Caritat et al. , GEEA, 2008 Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

Selected Results from Pilot Projects Profile 111 Fe Zn Profile 133 Riverina: Depth profiles Fe Zn Shallow (<10 cm) and deep (>50 cm) levels are geochemically distinct Caritat et al. , GEEA, 2008 Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

Gawler: Zn (ppm) in <180 um TOS I A (TOS) Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011) Caritat et al. , GEEA, 2008

$Grouped by size fraction: • Frequency (%) Cu (ppm) Selected Results from Pilot Projects$ Grouped by size fraction: • Frequency (%) Cu (ppm) Selected Results from Pilot Projects Cu in Gawler: variation between sites >> variation between grain sizes Cu (ppm) Grouped by site: • N = 72 (6 sites x 2 depths x 6 fractions ) • Finest size fraction has significantly elevated Cu concentrations compared to coarser • Thus, analysing a fine and a coarse fraction adds information • Regardless of depth or size fractions, some sites have significantly more elevated Cu values • This is why low-density geochemical mapping works! Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011) Caritat et al. , GEEA, 2008

National Geochemical Survey of Australia • • • In August 2006, the Australian Government announced support for Onshore Energy Security Program (OESP) $59 M over 5 years (2006 -2011) Uranium, thorium, geothermal, petroleum Geoscience Australia established a multi-disciplinary program to tackle this new focus (seismic, AEM, AWAGS 2, geothermal, NGSA, etc. ) NGSA is but one of the OESP projects Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

Aims of NGSA • To provide pre-competitive data and knowledge to support exploration for energy resources in Australia Specifically Ø To improve the existing knowledge on the concentration and distribution of energy-related elements such as uranium (U) and thorium (Th) at the national scale • But it will also provide new data for a range of commodity related elements such as gold (Au), copper (Cu), nickel (Ni) and zinc (Zn), among others, as well as several elements of interest for other applications, e. g. environmental management, at the national scale Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

Strategy for NGSA • • To keep costs down, an ultra-low sampling density strategy was adopted, backed by results from pilot projects Transported sediment: ‘a well-mixed composite sample of dominant lithologies upstreams’ as sampling medium Collect a proper sediment sample (fine-grained material, overbank/floodplain environment, outlet sediment, away from disturbed or polluted sites) Sample at 2 depths and separate 2 grain-size fractions to enhance geochemical information Analyse for major, minor & trace elements after total + aqua regia + Mobile Metal Ion. TM digests Identify areas where sediment chemistry indicates lithologies or mineralisation of interest Industry can focus further exploration investment in those selected areas and save $$ Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

National Geochemical Survey of Australia (NGSA) • • Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011) Landscape divided in large catchments Only mainland Australia + Tas Topographic analysis to split or amalgamate catchments Hydrologic analysis to determine catchment outlets Ignore catchments <1000 km 2 (mostly coastal) 91% coverage Emphasis on QA/QC from field to reporting

National Geochemical Survey of Australia (NGSA) • • • www. ga. gov. au/ngsa Contact: Patrice. de. Caritat@ga. gov. au Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011) Sample transported regolith at outlets of 1186 catchments over mainland Australia 123 of these catchments have been sampled in duplicate for quality control 6 other, large catchments also sampled higher up Average density ~1 site/5200 km 2 (similar to FOREGS European Atlas) 86% of the catchments have been sampled Over 6 million km 2 (or 80% of Australia) has been sampled

Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

National Geochemical Survey of Australia 0 -10 cm depth: Top Outlet Sediment (TOS) ca 60 -80 cm depth: Bottom Outlet Sediment (BOS) www. ga. gov. au/ngsa Air-dried, homogenised, split into ‘Bulk’, or sieved to <2 mm (‘Coarse’) and to <75 um (‘Fine’) grain size fractions Analysed for TOTAL, AQUA REGIA and MMITM element content Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

Geology Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

Validation of NGSA p. H against existing datasets Caritat et al. (2011) Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

Preliminary interpretation of NGSA results B C F G A D E H Caritat et al. (2011) Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

Comparison airborne vs soil geochemistry (p<0. 01) Existing U channel image ‘Corrected’ U channel image Green: 0 ppm U --- Red: 12 ppm U Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011) Wilford et al. (2011)

Comparison airborne vs soil geochemistry Wilford et al. (2011) Caritat & Cooper (2011) Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

Preliminary interpretation of NGSA results B C A F E Caritat et al. (2011) Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011) D

Possible causes of geochemical anomalies • • • Horizontal/lateral dispersion from ore deposit, mineralisation, secondary enrichment or alteration zone Vertical migration of chemical elements due to processes to be determined that could include groundwater (advection & diffusion), soil gas, plants or micro-organisms, electro-chemical currents over sulfide bodies or even lightning strikes Contamination due to mining activities (e. g. , dust), but (1) sites selected away from mines, (2) anomalies also in deeper BOS sample, (3) found equally around open-pit and underground mines, and (4) do not outline ore transport routes Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

Preliminary interpretation of NGSA results B C A Caritat et al. (2011) Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

Preliminary interpretation of NGSA results C B A D Caritat et al. (2011) Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

$Preliminary interpretation of NGSA results Concentration-Area (C-A) fractal analysis of Zn distribution “Background” “Anomalous”$ Preliminary interpretation of NGSA results Concentration-Area (C-A) fractal analysis of Zn distribution “Background” “Anomalous” Class 1 (4 -9 ppm) Class 2 (9 -40 ppm) Class 3 (40 -70 ppm) Class 4 (70 -105 ppm) Class 5 (>105 ppm) 9 mg/kg 40 72 Class 1 2 3 105 4 5 Zn deposit Zn occurrence Caritat et al. (2011) Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

Extraction Methods and Bio-Availability SGS Mann et al. (2011) Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

MMI extractable Ba (ppm) TM Caritat et al. (2011) Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

MMI extractable La (ppm) TM Caritat et al. (2011) Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

MMI extractable Au (ppb) TM Caritat et al. (2011) Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

MMI/Total: A measure of bio-availability? Mann et al. (2011) Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

Arid Zone Limestone Lithology Nullarbor Plain (limestone) Mann et al. (2011) Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

Arid Zone and/or Salt lakes Mann et al. (2011) Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

High Rainfall Zones c. f. Fe Mann et al. (2011) Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

Vis-NIR Spectroscopy Viscarra-Rossel et al. (2010, 2011) PC 1 PC 2 PC 3 Variance PC 1: hematite (-); 2: 1 clay minerals (+) PC 2: SOM, smectite (-); kaolinite (+) Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011) PC 3: illite, smectite, goethite? (-); SOM (+)

Vis-NIR Spectroscopy Viscarra-Rossel et al. (2010, 2011) 4 1 kao hem 1 1 3 M SO 2 2: 1 c 4 kao 2: 1 c 3 4 2: 1 c goe 3 PC clusters 1 (orange), 2 (red), 3 (blue) and 4 (green) with central composition (stars) and average reflectance and continuum-removed spectra (right) Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

Vis-NIR Spectroscopy Australian Soil Classification: Map of Soil Orders (Isbell 1996) 4 3 1 2 Distribution of PC clusters 1 (orange), 2 (red), 3 (blue) and 4 (green) and comparison to Map of Soil Orders (right) Viscarra-Rossel et al. (2010, 2011) Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

Vis-NIR Spectroscopy Normalised Iron Oxide Difference Index (NIODI): Red = hematite; Yellow = goethite probability Map of “true colour” RGB composite of Australian topsoil Viscarra-Rossel et al. (2010, 2011) NIODI uncertainty map (right) Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

Conclusions • • • Geochemical surveys provide a fundamental dataset for decision making Low to ultra-low density geochemical surveys yield data that makes geological sense Pilot projects in the Riverina, Gawler and Thomson areas provided proof-of-concept for the NGSA The Onshore Energy Security Program from the Australian Government provided the financial support for the NGSA From 2007 to 2011, field work was carried out, sample preparation and analysis took place, and map production was completed Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

Conclusions • • • A new national geochemical dataset is available Comparison with independent datasets indicates reliability Data quality assessed in dedicated report NGSA data identifies a number of areas that may have potential for discovery, e. g. in terms of U, Th, Au, Pb, Zn, REEs as shown here >500 geochemical maps available on website www. ga. gov. au/ngsa The dataset and atlas are useful pre-competitive assets in the exploration for energy and mineral resources Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)

Acknowledgments • • • Australian Government for OESP funding All States and Northern Territory for entering a National Geoscience Agreement Land owners for access to sampling sites Field sampling teams from State/NT geoscience agencies: Ø Gary Burton, Paul Flitcroft, Trevor Hegvold (NSW) Ø Andrew Wygralak, Darren Bowbridge, Simon Fanning, Rod Maier, Clarke Petrick (NT) Ø Joseph Tang, Phil Boyle, Stanley Briggs, Dominic Brown, Philip Burrows, Leonard Cranfield, Terry Denaro, Glenys Diprose, Courteney Dhnaram, Melanie Fitzell, Dudley Fulton, Janice Harley, Jimmy Lam, Mark Livingstone, David Mc. Intyre, Jack Skinner, Jack Ryle (Qld) Ø Roger Fidler, Katherine Brownlie, Stacey Curtis, Tania Dhu, Adrian Fabris, Claire Fricke, Georgina Gordon, Tiphaine Lavigne, Josine Parsons, Steve Sutton, Antony Whiting, Tania Wilson, Ben Uppill (SA) Ø Geoff Green, Shane Heawood (Tas) Ø Emily House, Ken Sherry, Rachel Roberts (Vic) Ø Colin Strickland, Richard Langford, Paul Morris, Amanda Thomson (WA) Sample preparation and analysis team: Ø Christian Thun, Liz Webber, Bill Pappas, Matthew Brown, Jessica Byass, Nounou Chanthapanya, John Furlonger, Amber Green, Keith Henderson, Zia Husain, Bozana Krsteska, Benjamin Linehan, Andris Lukss, Ador Makuei, Lucy Mc. Cabe, Gregory O’Connell, Billie Poignand, Mike Smith, Helen Tait, Kylia Wall, Tony Watson (GA) For assistance and collaboration on various aspects: Ø Michelle Cooper, Evgeniy Bastrakov, Lindsay Highet, Subhash Jaireth, Megan Lech, Dan Mc. Ilroy, Andrew Mc. Pherson, Donna Phillips, Lara Sedgmen, John Wilford (GA); John Greenfield, John Watkins (GSNSW); Martin Fairclough (PIRSA); Paul Mc. Donald, Adele Seymon (GSV); Janet Stein, Mike Hutchinson, Peter Veth (ANU); Clemens Reimann (NGU); Rudi Dutter (VUT); Alan Mann (Consultant); Pierrette Prince (SGS); Raphael Viscarra. Rossel (CSIRO); Eric Grunsky (GSC) Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5 -7 Sep 2011)