E, thats a tough one,

Archean lode gold deposits occur in a variety of lithological and structural settings in

greenstone belts of the Canadian Shield. “In general, the ores are derived from

hydrothermal fluids and consist of veins (open space) filling and altered wall rock

(replacement or metasomatism). The veins generally consist of coarse or cherty quartz with

lesser amounts of albite and carbonate, tourmaline, sericite and chlorite. In some systems,

tourmaline or carbonate may be the principal constituent of the veins. Opaque minerals

rarely constitute more than 5% of a vein. Pyrite is invariably present and is the most

abundant sulphide; pyrrhotite and arsenopyrite are common, and other opaque minerals may

include galena, sphalerite, chalcopyrite, molybdenite, stibnite, tellurides and scheelite. In

greenschist facies rocks, the altered wall rock immediately adjacent to the veins, is

characterized by minerals that also occur in the veins: carbonates, quartz, sericite, albite and

pyrite” (Roberts

et al, 1990). Fuchsite is also present in many major deposits (Thorpe et al,

1994).

Typically, ore grade gold occurs in the quartz, and in small fractures in quartz, and in the

wall rock where it is usually associated with iron sulphides. It is not uncommon for most or

all of the gold of an ore zone to be contained in wall rocks immediately adjacent to veins