RES/(m) 
eposit Scale 
  
5-8 
5-8 
10-20 
10-20 
5-8 
ucs 
ES.(m) 
posit Scale 
5-8 
5-8 
10-20 
tic zone. 
RARE 
  
  
Table 4. Spectral and spatial requirements for the volcanic-hosted deposits, low sulfidation subtype. 
  
CHARACTERISTIC DESCRIPTION SPECTRAL RANGE (um) 
Multispec. 
SPATIAL RES.(m) 
Hyperspec.* Recon Deposit Scale 
  
Primary Alteration** Narrow quartz veins & silicif. 2.15-2.35 9.7, 10.0 10-20 4-6 
wall rock, stockwork w/ adularia, 9.5-10.5 2.19,221& 
sericite, illite, kaolinite, chlorite, 2.35, 2.33 
calcite, propylitic envelope 
Secondary Alterat. Restricted jarosite, goethite, 0.6-0.7, 0.9, 0.95 10-20 4-6 
(alunite) 0.8-1.0 (2.18) 
Host Rocks Rhyolitic to andesitic flows, VNIR,TIR TIR bands 20-30 10-20 
tuffs & breccia, hypabyssal SWIR 
porphyries 
Zoning*** Quartz-adularia-sericite(illite)- 9.5-10.5 9.7, 10.0, 5-8 3-4 
kaolinite (montmor.), chlorite, 2.15-2.35 2.19,2.:21, 
propylitic 2,38,2.33 
Structure Caldera ring and radial fract., VNIR, TIR Spectral feat. 20-80 5-8 
high angle faults and shears, SWIR, above 
grabbens, domes Microwave 
Vegetation Decrease over mineralization NIR 0.7-0.8 10-20 4-6 
and alteration (linear patterns) 
* Position of some key absorption maxima or emission minima. 
** Alteration is weak and narrowly to moderately confined. Sophisticated enhancement techniques and multiple 
indicators may be required for detection. 
*** From central quartz-sulfide-adularia vein, outward to sericite (illite) through argillic to propylitic assemblages. 
Concentration of adularia may be adequate for detection with TIR bands. 
  
  
Table 5. Spectral and spatial requirements for gold skarns and disseminated deposits peripheral to porphyry 
copper/molybdenum deposits. 
  
  
CHARACTERISTIC DESCRIPTION SPECTRAL RANGE (um) SPATIAL RESOLUT.(m) 
Multispec. Hyperspec. * Recon Deposit Scale 
Primary Alteration** Garnet, pyroxene, epidote, 2.15-2.35 10.5, 9.7, 20-30 8-10 
chlorite, silica, kaolinite & 2.34, 2.21 
illite, propylitic, decalcif. 2.19.2.33 
Secondary Alterat. Jarosite, goethite, hematite, 0.6-0.7, 0.9,0.95, 20-3 8-10 
(argillic minerals) 0.8-1.0 0.85 
Host Rocks Carbonates & assoc. seds. VNIR, TIR 2.33, 10.5 20-30 8-10 
intermediate composition SWIR Other TIR 
plutons & assoc. volcanics 
Zoning*** Garnet-pyroxene, epidote, SWIR, Complex:10.5 10-20 8-10 
chlorite, pyrite-marble; or TIR 9.7,2.33, 2.34 
argillic/propylitic interface (9, 93, 83) 
of porphyry Cu/Mo dep. 
Structure Intrusive contacts, regional SWIR, TIR, Spectral feat. 20-80 10-20 
faults, strata disruptions Microwave above 
Vegetation Species variation NIR 0.7-0.8 20-30 38-10 
* 
Position of some key absorption maxima or emission minima. 
xk 
Alteration zones are large, but since skarn is composed of rock forming silicates, alteration is not typically 
obvious. Detection may rely on presence of iron oxides. 
*** Garnet central to pyroxene and epidote. Chlorite may be ubiquitous if retrograde. 
  
643 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B7. Vienna 1996