An overview of vis-nir-swir field spectroscopy - Spectral International
An overview of vis-nir-swir field spectroscopy - Spectral International
An overview of vis-nir-swir field spectroscopy - Spectral International
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Major Global Deposits<br />
EL PEÑON, Chile MARTA, Peru<br />
ESQUEL, Argentina ROUND MOUNTAIN, Nevada<br />
CERRO VANGUARDIA, Argentina COMSTOCK, Virginia City, Nevada<br />
HISHIKARI, Japan SLEEPER, Nevada<br />
GOSAWONG , Indonesia MIDAS, Nevada<br />
KUPOL, Russia WAIHI , New Zealand<br />
ROSIA MONTANA, Romania GOLDEN CROSS, New Zealand<br />
LIHIR, PNG CERRO BAYO, Chile<br />
TRES CRUCES, Peru KORI KOLLO, Bolivia<br />
COMMON ALTERATION MINERALS in LOW SULFIDATION SYSTEMS<br />
ILLITE KAOLINITE CHLORITES<br />
ILLITE/SMECTITE BUDDINGTONITE EPIDOTE<br />
Montmorillonite ADULARIA* ZEOLITES<br />
QUARTZ CALCITE HEMATITE<br />
*Adularia is not infrared active.<br />
Alteration types associated with Low Sulfidation Systems<br />
Silicification is extensive in ores as multiple generations <strong>of</strong> quartz and<br />
chalcedony and commonly is accompanied by adularia and calcite. Pervasive<br />
silicification in vein envelopes is flanked by sericite-illite-kaolinite assemblages.<br />
Intermediate argillic alteration [kaolinite-illite-montmorillonite (smectite)] forms<br />
adjacent to some veins; advanced argillic alteration (kaolinite-alunite) may form<br />
along the tops <strong>of</strong> mineralized zones. Propylitic alteration dominates at depth and<br />
peripherally. Panteleyev, A.(1996). Buddingtonite can also be present.<br />
QSA Quartz-Sericite-<br />
Adularia<br />
Figure 21 - Plot shows illite, mixed layer<br />
illite/smectite, montmorillonite, quartz, calcite,<br />
dolomite, kaolinite and pyrite.<br />
20<br />
Silicic<br />
Figure 22 - Silicic alteration is pervasive<br />
replacement <strong>of</strong> the rock by silica minerals.<br />
Minerals include opal, chalcedony, quartz,<br />
hematite, and pyrite.
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