Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
The National Geochemical Survey of Australia
Patrice de CaritatGeoscience Australia
A collaborative project under National Geoscience Agreements with New South Wales Department of Primary Industries, Mineral Resources Tasmania,
GeoScience 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
Total element concentrations Weak digestion concentrations 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: Purpose (minex, environmental, land-use, etc.) Size of area to cover (strategic v tactical) Sampling medium Sampling density Constraints: time, resources, history, etc
Gd+Sm
Ti
Neutron SpectrometryDataElphic et al. (1998, 2000)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
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
• Curnamona: Broken Hill region; base metal, Cu-Au
• Riverina: Agriculture, Murray Basin; Au, base metal
• Gawler: Arid, flat, aeolian influence; Olympic Dam Fe-
oxide-Cu-Au-U, Au• Thomson:
Eromanga/GAB Basin cover; borders on Curnamona and Cobar (base metal, Cu, Au) districts
Pilot survey Approx area (km2)
Number of sampling sites
Average sampling density (1 site per X km2)
Curnamona 61,915 199 311
Riverina 122,976 142 866
Gawler 53,636 48 1117
Thomson 209,824 99 2119
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
Riverina: Depth profiles
Fe
Fe
Pro
file
133
Pro
file
11
1 Zn
Zn
Caritat et al., GEEA, 2008
Shallow (<10 cm) and deep (>50 cm) levels aregeochemically distinct
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
Lakes
Australian coastline
Catchment Outline
Zn (<180 um) (ppm)
1 - 8
9 - 22
23 - 30
31 - 40
41 - 63
Hutchinson Group
Ifould Complex
Tunkillia Suite Granite
Glenloth Granite
Sleeford Complex
Harris Greenstone Belt Volcanics
0 60 12030
Kilometres
Hiltiba SuiteGranite
Upper Gawler Range Volcanics
Lower Gawler Range Volcanics
St Peters Suite Granite
¯
133°0'E
133°0'E
133°30'E
133°30'E
134°0'E
134°0'E
134°30'E
134°30'E
135°0'E
135°0'E
135°30'E
135°30'E
136°0'E
136°0'E 136°30'E
33°3
0'S
33°0
'S
33°0
'S
32°3
0'S
32°3
0'S
32°0
'S
32°0
'S
31°3
0'S
31°3
0'S
31°0
'S
31°0
'S
30°3
0'S
30°3
0'S
(TOS)
AI
Gawler: Zn (ppm) in <180 um TOS
0 60 12030
Kilometres
Caritat et al., GEEA, 2008
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
Selected Results from Pilot Projects
• Cu in Gawler: variation between sites >> variation between grain sizes
Grouped by size fraction:
Grouped by site:
Cu
(ppm
)
Fre
quen
cy (
%)
Cu
(ppm
)
Caritat et al., GEEA, 2008
A. <75 μm B. 75-180 μm C. <180 μm D. 180-500 μm E. 500-1000 μm F. 1000-2000 μm
• 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)
National Geochemical Survey of Australia
• In August 2006, the Australian Government announced support for Onshore Energy Security Program (OESP)
• $59M over 5 years (2006-2011)• Uranium, thorium, geothermal, petroleum• Geoscience Australia established a multi-
disciplinary program to tackle this new focus (seismic, AEM, AWAGS2, 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 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 IonTM 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)
• 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 km2 (mostly coastal)
• 91% coverage• Emphasis on QA/QC
from field to reporting
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
National Geochemical Survey of Australia (NGSA)
• 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 km2 (similar to FOREGS European Atlas)
• 86% of the catchments have been sampled
• Over 6 million km2 (or 80% of Australia) has been sampled
www.ga.gov.au/ngsawww.ga.gov.au/ngsa
Contact: [email protected]
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
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)
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 contentwww.ga.gov.au/ngsa
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
Archean cratons & basins
Paleoproterozoic basins &complexes
Neoproterozoic basins
Paleozoic metamorphic & igneous rocks
Cenozoic & Quaternary sediments
Mesozoic sedimentary basins
Mesoproterozoic basins &complexes
Archean cratons & basins
Paleoproterozoic basins &complexes
Neoproterozoic basins
Paleozoic metamorphic & igneous rocks
Cenozoic & Quaternary sediments
Mesozoic sedimentary basins
Mesoproterozoic basins &complexes
Geology
Distribution of MMI™ extractable Ga (ppm) in Australia
Distribution of MMI™ extractable La (ppm) in Australia
Distribution of MMI™ extractable Cu (ppm) in Australia
ConclusionsThe distributions of MMI™ extractable elements in catchment outlet sediments from Australia demonstrate that geochemical signaturesfrom the underlying and/or surrounding bedrock, whether barren or mineralised, can be detected and interpreted in terms of lithology or mineralisation potential. Many known deposits are reflected by elevated MMI™ values, and many more anomalous results indicate potential for future mineral discovery.
ReferencesCaritat & Cooper, 2011. Geoscience Australia Record 2011/20 (Available at: http://www.ga.gov.au/ngsa)SGS, 2011. MMI™ Theory (Available at: http://www.geochem.sgs.com/mmi-theory.htm)
Geology
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
Validation of NGSA pH against existing datasets
Caritat et al. (2011)
Caritat et al. (2011)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
A
C
B
D
E
F
G
H
Preliminary interpretation of NGSA results
Caritat et al. (2011)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
Comparison airborne vs soil geochemistry
‘Corrected’ U channel image
TOS U ppm vs Airborne eU ppm (300m radius average)with > 25% 2mm fraction removed
R2 = 0.3319
0
1
2
3
4
5
6
7
8
0 2 4 6 8 10 12 14Soil U ppm
Air
bo
rne
eU
pp
m
(p<0.01)
Existing U channel image
Green: 0 ppm U --- Red: 12 ppm U Wilford et al. (2011)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
Caritat & Cooper (2011)
TOS Th ppm vs Airborne eTh ppm (300m radius average)with > 25% 2mm fraction removed
R2 = 0.5768
0
5
10
15
20
25
30
35
40
0 5 10 15 20 25 30 35 40 45Soil Th ppm
Air
bo
rne
eT
h p
pm
Wilford et al. (2011)
Comparison airborne vs soil geochemistry
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
B
A
D
C
E
F
Preliminary interpretation of NGSA results
Caritat et al. (2011)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
• 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
Possible causes of geochemical anomalies
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
B
AC
Preliminary interpretation of NGSA results
Caritat et al. (2011)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
B
A
D
C
Preliminary interpretation of NGSA results
Caritat et al. (2011)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
Preliminary interpretation of NGSA resultsConcentration-Area (C-A) fractal analysis of Zn distribution
Caritat et al. (2011)
9 mg/kg40
72
105
“Background” “Anomalous”
Class 1 2 3 4 5
Class 1 (4-9 ppm)Class 2 (9-40 ppm)Class 3 (40-70 ppm)Class 4 (70-105 ppm)Class 5 (>105 ppm)
Zn depositZn occurrence
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
Extraction Methods and Bio-Availability
Mann et al. (2011)
SGS
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
Ba (MMI)<0.01-0.180.18-0.340.34-0.480.48-0.650.65-0.890.89-1.171.17-1.501.50-2.192.19-3.363.36-15.3
MMITM extractable Ba (ppm)
Caritat et al. (2011)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
La (MMI)<0.001-0.0020.002-0.0050.005-0.0100.010-0.0210.021-0.0400.040-0.0680.068-0.1200.120-0.2010.201-0.3360.336-3.310
La (MMI)<0.001-0.0020.002-0.0050.005-0.0100.010-0.0210.021-0.0400.040-0.0680.068-0.1200.120-0.2010.201-0.3360.336-3.310
MMITM extractable La (ppm)
Caritat et al. (2011)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
Au (MMI)<0.1 ppb<0.1-0.10.1-0.20.2-0.30.3-0.40.4-0.50.5-0.70.7-0.90.9-1.31.3-1.98
Au (MMI)<0.1 ppb<0.1-0.10.1-0.20.2-0.30.3-0.40.4-0.50.5-0.70.7-0.90.9-1.31.3-1.98
Au (MMI)<0.1 ppb<0.1-0.10.1-0.20.2-0.30.3-0.40.4-0.50.5-0.70.7-0.90.9-1.31.3-1.98
Ernest Henry
Vera Nancy
Osborne
Mt Rawdon
Sarsfield
The Peak, Tritton,Endeavor, North Parkes
Cowal, Peak Hill,Ridgeway, Cadia
Stawell, FostervilleBroken Hill
Roseberry
Olympic Dam
Prominent Hill
Coyote The GranitesTelfer
Plutonic
Meekatharra
Jundee-Nimary
Golden Grove
Agnew, Thunderbox,Hill 50, Lalwers, GrannySmith, Darlot-Centenary
Sons of Gwalia
Marvel Loch, Bullfinch
Bounty, Frog’s Leg,Norseman, Kundana
Primarily Au MinePrimarily Cu or Zn MinePrimarily Au MinePrimarily Cu or Zn MinePrimarily Au MinePrimarily Cu or Zn Mine
MMITM extractable Au (ppb)
Caritat et al. (2011)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
Average % Bioavailability
NGSA Overbank Sampling
Based on 1190 Comparisons MMI vs Total Analysis for Ca, Fe, P1176 for Cu, 1188 for K, 1161 for Mg, 1138 for Mn, 1169 for Zn
Ca Cu Fe K Mg Mn P Zn0
2
4
6
8
10
12
14
16
% Bioavailability
Mann et al. (2011)
MMI/Total: A measure of bio-availability?
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
110 115 120 125 130 135 140 145 150 155-45
-40
-35
-30
-25
-20
-15
-10
0
200
400
600
800
NGSA Overbank SamplingIsotropic Kriging MMI ImageGeoscience Australia - SGS
. O verbank Sam pling Location
MMI Ca(ppm)Ca
Nullarbor Plain(limestone)
Arid Zone
LimestoneLithology
Mann et al. (2011)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
110 115 120 125 130 135 140 145 150 155-45
-40
-35
-30
-25
-20
-15
-10
0
50
100
150
200
NGSA Overbank SamplingIsotropic Kriging MMI ImageGeoscience Australia - SGS
. O verbank Sam pling Location
MMI K(ppm)K
Arid Zoneand/orSalt lakes
Mann et al. (2011)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
110 115 120 125 130 135 140 145 150 155-45
-40
-35
-30
-25
-20
-15
-10
0
2
4
6
8
NGSA Overbank SamplingIsotropic Kriging MMI ImageGeoscience Australia - SGS
. O verbank Sam pling Location
MMI Mn(ppm)Mn
HighRainfallZonesc.f. Fe
Mann et al. (2011)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
Vis-NIR Spectroscopy
PC1 PC2 PC3
PC1: hematite (-);2:1 clay minerals (+)
PC2: SOM, smectite (-); kaolinite (+)
Variance Variance Variance
PC3: illite, smectite, goethite? (-); SOM (+)
Viscarra-Rossel et al. (2010,2011)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
Vis-NIR Spectroscopy
PC clusters 1 (orange), 2 (red), 3 (blue) and 4 (green)
with central composition (stars) and average reflectance and continuum-removed spectra
(right)
1
2
4
3
1
2
3
4
1
2
3
4
SOM
SOM
kao
hem
goe
2:1
c2:1
c
2:1
c
kao
2:1
c
2:1
cViscarra-Rossel et al. (2010,2011)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
Vis-NIR Spectroscopy
Australian Soil Classification: Map of Soil Orders (Isbell 1996)
Distribution of PC clusters 1 (orange), 2 (red), 3 (blue) and 4 (green) and comparison
to Map of Soil Orders (right)
1
2
4
3
Viscarra-Rossel et al. (2010,2011)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
Vis-NIR SpectroscopyMap of “true colour” RGB composite
of Australian topsoil
NIODI uncertaintymap (right)
Normalised Iron Oxide Difference Index (NIODI):Red = hematite; Yellow = goethite probability
Viscarra-Rossel et al. (2010,2011)
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
• 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
Conclusions
Geochemical Atlas of Cyprus Symposium (Lefkosia, Cyprus, 5-7 Sep 2011)
• 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
Conclusions
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:
Gary Burton, Paul Flitcroft, Trevor Hegvold (NSW) Andrew Wygralak, Darren Bowbridge, Simon Fanning, Rod Maier, Clarke Petrick (NT) 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 McIntyre, Jack Skinner, Jack Ryle (Qld)
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)
Geoff Green, Shane Heawood (Tas) Emily House, Ken Sherry, Rachel Roberts (Vic) Colin Strickland, Richard Langford, Paul Morris, Amanda Thomson (WA)
• Sample preparation and analysis team: 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 McCabe, Gregory O’Connell, Billie Poignand, Mike Smith, Helen Tait, Kylia Wall, Tony Watson (GA)
• For assistance and collaboration on various aspects: Michelle Cooper, Evgeniy Bastrakov, Lindsay Highet, Subhash Jaireth, Megan Lech, Dan
McIlroy, Andrew McPherson, Donna Phillips, Lara Sedgmen, John Wilford (GA); John Greenfield, John Watkins (GSNSW); Martin Fairclough (PIRSA); Paul McDonald, 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)
Top Related