Here's more, this time in The Saskatchewan Exploration and Development Highlights 2004, from
www.ir.gov.sk.ca/...
tinyurl.com/48pmeFrom page 7 of the report:
"Uranium ore is generally focused at or near the basal
unconformity of the Athabasca Group. Proximity of
ore to graphite-bearing pelitic gneiss in the basement
is a common spatial association. All deposits are
structurally controlled. They occur along reactivated
basement shear zones, generally in reverse faults, that
intersected or were focused in graphitic lithologies.
In over thirty years since the introduction of the
unconformity model, debate continues as to the
relative importance of the unconformity, structure,
graphite-bearing units in the basement and fluid
mixing for optimal ore deposition and concentration."
And later on the same page:
"The highest grade ore typically occurs in massive lenses, which straddle the unconformity. Extensive alteration haloes penetrate both the Athabasca Group and crystalline basement. Hydrothermal alteration
assemblages include chlorite, tourmaline,
hematite (several episodes),
silica and dolomite (e.g. Hoeve, 1984). Regional-scale, clay-alteration zones of
illite are common along the major structures that controlled ore deposition and are an important exploration criterion (e.g. Sopuck et al., 1983)."
Lookin' better all the time...
Bo
Urban