Gold mineralization within the Orion Gold Project belongs
to the low sulphidation-type epithermal model.
This group of gold deposits is one of the world’s major
sources of gold and includes deposits such as Round Mountain,
USA (16 million ounces gold), Comstock, USA (7.7 million ounces
gold) and Tayolita, Mexico (9.6 million ounces gold).
Low sulphidation deposits are characterized by:
- Subvertical quartz and banded chalcedony veins, stockwork
and breccia within extensive zones of hydrothermal alteration
- Sericite/illite is the most common alteration proximal
to the ore
- Chloritic (propylitic) alteration is more distal
- Adularia and chalcedony are characteristic alteration
minerals
- Typically low tonnage and high grade (Bonanza style)
- Pyrite is the dominant sulphide mineral with some arsenopyrite,
sphalerite, galena and silver sulphides
- Geochemically zoned with As and Sb at the top, Au and
Ag in the middle and Cu, Pb, Zn at the bottom of the system
- Deposits are structurally controlled along caldera and
volcanic faults
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