Geology Reference
In-Depth Information
a
Perched
ore
sandstone
Grey strata
Quartz crystal
zone
Highly clay-
altered
Clay
cap
Unconformity
ore
regolithe
Altered
Basement
Basement (meta-
-sedimentary rocks)
Basement ore
b
Mo halo; unaltered silicates
pre-ore pyrite; calcite and
carbonaceous matter
preserved
Major species
in solution
UO
2
(CO
3
)
3
2-
UO
2
(CO
3
)
3
4-
H
2
VO
4
-
HAsO
4
2-
SeO
4
2-
MoO
4
2-
Altered
(oxidized)
Alteration
envelope
Uranium ore
zone
unaltered
(reduced)
hematite
Calcite leached
Metals leached
Organic carbon destroyed
Feldspars and
Fe-Mg silicate altered
pechblende
ore-stage pyrite
calcite
organic carbon
V, Mo, Co, Cu, As, Se
goethite
siderite
Se, S
c
Euhedral / framboidal
pyrite
alteration envelope
Fig. 4.12 Illustration of the geology and origin of uranium deposits (a)roll-front,(b)unconformity-
related deposits (Modified from Jefferson et al.
2008
and Robb
2005
)
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