Spectral Geology
2 June 2009
Lecture series presented by the UWA Student Chapter
of the Society of Economic Geologists
Objective
• Asking the right questions!
• Mineral system analysis
• Integration with geophysical and geochemical data
To show how remote (airborne and satellite imagery) and
field/drill-core (e.g. ASD™, microFTIR™ and Hylogger™)
spectral data can be applied for exploration and research.
Outline9:00 - 9:15: Introduction to spectral geology and the available
technologies - Carsten Laukamp (CET)
9:15 - 10:00: Is spectral geology complementary to current geophysics? - Rob Hewson (CSIRO)
10:00 - 10:20: The application of ASTER and ASD data at Pataz Goldfields, Northern Peru - Wally Witt (CET)
10:20 - 10:35: Coffee break
10:35 - 11:20: Mine scale spectral geology - Ore characterisation using "HyLogging Systems” - Erick Ramanaidou (CSIRO)
11:20 - 12:05: 3D spectral geology - mineral systems, exploration targeting and C3DMM - Tom Cudahy (CSIRO)
12:05 - 12:30: QandA - led by SEG Student Chapter and Carsten Laukamp
Mineral Mapping Theory
Mineral Mapping Theory
Mineral Mapping Theory
Mineral Mapping Theory• Diagnostic absorption features of hydroxyl mineral groups in the SWIR
– Al(OH): 2170 - 2210 nm
•Topaz, Pyrophyllite, Kaolinite, Montmorillonite, Muscovite, Illite
– “Mg(OH)”: 2300 - 2400 nm•Chlorite, Talc, Epidote, Amphibole, Antigorite, Biotite, Phlogopite
– “Fe(OH)”: 2250 - 2300 nm•Jarosite, Nontronite,
Saponite, Hectorite
– Si(OH): 2240 nm (broad)•Opaline silica
Composition of Minerals
Muscovite
PhengitePhengite
(Mg,Fe)(Mg,Fe)octoct Si Sitettet = Al = Aloctoct Al Al tettet
From Scott and Yang, 1997
mineralminers.com/html/musmins.stm
Al, Fe, Mg, Cr, V
Si, Al
K, Na, Ca
octahedral
tetrahedral
interlayer
• white mica composition
• crystallinity of white micas or clay minerals
• Mg# of chlorites
• carbonate composition
• …
Spectral-Mineral Wavelength Regions
-12
13.5
39
64.5
90
115.5
0.35 0.85 1.35 1.85 2.35
-12
13.5
39
64.5
90
115.5
7.35 8.35 9.35 10.35 11.35 12.35
Electro-Magnetic Spectrum - Wavelength in Micrometer
Gro
und
Ref
lectanc
e (offse
t fo
r clarit
y)
Gro
und
Em
issivity (o
ffse
t fo
r clarit
y)
dark soil
green vegetation
green vegetation
dark soil
limestone
limestone
sandstone
sandstone
dry vegetationdry vegetation
ARGUS
Hymap
Aster
Landsat TM
From Peter Hausknecht
VNIR
iron oxidesREEs
vegetation
SWIR
OH-bearing hydroxyls(kaolin, chlorite, mica, amphibole)
sulphatescarbonates
Thermal Infrared
Non-OH-bearing silicates(quartz, feldspars, pyroxene, garnet)
sulphatescarbonates
Visible Near Infrared Short Wave Infrared
0.45
0.65
0.85
1.05
1.25
1.45
1.65
1.9 2.1 2.3 2.5
Wavelength (micrometer) =>
Laboratory
ARGUS / AVIRIS
HYMAP
ASTER
Landsat TM
Spectral Resolution
Available Technologies(examples)
• Field spectral devices:
• PIMA
• Fieldspec Pro
• TERRASPEC
• microFTIR
• Hylogger system:
• HyLogger™
• HyChips™
• TIR-Logger™
• Remote sensing devices:
• airborne (e.g.HyMap)
• satellite (e.g. ASTER)
Field Spectral DevicesAnayltical spectral devices (ASD, http://www.asdi.com)• Fieldspec Pro
•350-2500 nm•10 nm spectral
resolution @ SWIR •~AUD$100K
• TERRASPEC•More robust fibre•contact
TERRASPEC
Integrated Spectronics (ISPL, http://www.intspec.com)• PIMA (Portable Infrared Mineral Analyser)
• 1300-2500 nm• 8 nm resolution• contact• ~AUD$40K
Fieldspec Pro
Hylogging Suite• HyLogger™
• 0.4-2.5 m • FTIR (D&P)• diamond drill core logging• ~700m / day
• 1 cm line-profile footprint
• HyChips™• 0.4-2.5 m • ASD based• RAB/RC drill chip tray logging• 45 trays / hour (up to 3000 * 1 m samples p/d)
• TIR-Logger™• 2.5 -20 m• FTIR (D&P) • Diamond drill (and Chips)• ~700m / day • 1 cm line-profile footprint
Remote Sensing Spectral Devices
Airborne HyMap
Spectral Configuration – 128 channels
Module Spectral range Bandwidthacross module
Average spectralsampling interval
VIS 0.45 – 0.89 um 15 – 16 nm 15 nmNIR 0.89 – 1.35 um 15 – 16 nm 15 nm
SWIR1 1.40 – 1.80 um 15 – 16 nm 13 nmSWIR2 1.95 – 2.48 um 18 – 20 nm 17 nm
www.hyvista.com
• Australian sensor• Sydney-based• NASA-approved• high SNR• 126 bands• 0.4-2.5 m• 3-30 m pixel• 512 pixel swath• whiskbroom• fully calibrated
Airborne HyMapHyMap products delivered for the Qld Next Generation Mineral Mapping Project (excerpt) (http://www.em.csiro.au/NGMM/):
• Natural colour basemap;• False colour basemap; • Green vegetation content;• Dry vegetation content;• Iron oxide content;• Hematite/Goethite ratio;• Ferrous iron content; • Kaolin content;• Kaolin crystallinity;• Al-smectite content;• Al-smectite composition;• White mica (paragonite-muscovite-phengite)
content;• White mica composition;• White mica crystallinity;• MgOH (cc/dol/chl/ep/amph) content;• MgOH (cc/dol/chl/ep/amph) composition;• Ferric iron and MgOH;• Ferrous iron and MgOH;• Chlorite-Epidote content;• Epidote content;• Opaques;• Hydrated silica
false colour white mica composition
2190 nm
2215nmAl-rich Al-poor
5kmBlock H
ASTER
(Advanced Spaceborne Thermal Emission and Reflective Radiometer)
• “Next generation” geology-tuned satellite sensor:
• 14 spectral bands including 6 SWIR and 5 TIR geological bands (+ DEM)
• 15 m VNIR• 30 m SWIR• 90 m TIR
• Pushbroom for VNIR and SWIR
• Whiskbroom for TIR
• Significant Instrument/Data Issues• atmospheric correction, SWIR X-talk, TES
www.asterweb.jpl.nasa.govwww.science.aster.ersdac.or.jp
Software• TSG (the Spectral Geologist)
–Field and core spectra
• TSA (the Spectral Assistant)
• TSG-Core Distributed through Ausspec (www.ausspec.com)
• ENVI (Environment for Visualising Images) (www.ittvis.com)
–Hyperspectral images
–Field spectra
• ERMapper (www.ermapper.com)
–ASTER wizard
• CSIRO/HyVista Suite
–ASTER and hyperspectral multi-scene processing
• C-HyperMAP
• C-SatMAP
–IDL based
Outline9:00 - 9:15: Introduction to spectral geology and the available
technologies - Carsten Laukamp (CET)
9:15 - 10:00: Is spectral geology complementary to current geophysics? - Rob Hewson (CSIRO)
10:00 - 10:20: The application of ASTER and ASD data at Pataz Goldfields, Northern Peru - Wally Witt (CET)
10:20 - 10:35: Coffee break
10:35 - 11:20: Mine scale spectral geology - Ore characterisation using "HyLogging Systems” - Erick Ramanaidou (CSIRO)
11:20 - 12:05: 3D spectral geology - mineral systems, exploration targeting and C3DMM - Tom Cudahy (CSIRO)
12:05 - 12:30: QandA - led by SEG Student Chapter and Carsten Laukamp