Page 173 - Introduction to Mineral Exploration

156 C.J. MOON

TABLE 8.1 Elemental associations and associated elements (pathfinders) useful in exploration. (Largely from
Rose et al. 1979 with some data from Beus & Grigorian 1977, p. 232, and Boyle 1974.)

Type of deposit Major components Associated elements
Magmatic deposits
Chromite ores (Bushveld) Cr Ni, Fe, Mg
Layered magnetite (Bushveld) Fe V, Ti, P
Immiscible Cu–Ni–sulfide (Sudbury) Cu, Ni, S Pt, Co, As, Au
Pt–Ni–Cu in layered intrusion (Bushveld) Pt, Ni, Cu Sr, Co, S
Immiscible Fe–Ti–oxide (Allard Lake) Fe, Ti P
Nb–Ta carbonatite (Oka) Nb, Ta Na, Zr, P
Rare–metal pegmatite Be, Li, Cs, Rb B, U, Th, rare earths
Hydrothermal deposits
Porphyry copper (Bingham) Cu, S Mo, Au, Ag, Re, As, Pb, Zn, K
Porphyry molybdenum (Climax) Mo, S W, Sn, F, Cu
Skarn–magnetite (Iron Springs) Fe Cu, Co, S
Skarn–Cu (Yerington) Cu, Fe, S Au, Ag
Skarn–Pb–Zn (Hanover) Pb, Zn, S Cu, Co
Skarn–W–Mo–Sn (Bishop) W, Mo, Sn F, S, Cu, Be, Bi
Base metal veins Pb, Zn, Cu, S Ag, Au, As, Sb, Mn
Sn–W greisens Sn, W Cu, Mo, Bi, Li, Rb, Si, Cs, Re, F, B
Sn–sulfide veins Sn, S Cu, Pb, Zn, Ag, Sb
Co–Ni–Ag veins (Cobalt) Co, Ni, Ag, S As, Sb, Bi, U
Epithermal precious metal Au, Ag Sb, As, Hg, Te, Se, S, Cu
Sediment hosted precious metal (Carlin) Au, Ag As, Sb, Hg, W
Vein gold (Archaean) Au As, Sb, W
Mercury Hg, S Sb, As
Uranium vein in granite U Mo, Pb, F
Unconformity associated uranium U Ni, Se, Au, Pd, As
Copper in basalt (L. Superior type) Cu Ag, As, S
Volcanic-associated massive sulfide Cu Cu, S Zn, Au
Volcanic-associated massive sulfide Zn, Pb, Cu, S Ag, Ba, Au, As
Zn–Cu–Pb
Au–As rich Fe formation Au, As, S Sb
Mississippi Valley Pb–Zn Zn, Pb, S Ba, F, Cd, Cu, Ni, Co, Hg
Mississippi Valley fluorite F Ba, Pb, Zn
Sandstone-type U U Se, Mo, V, Cu, Pb
Red bed Cu Cu, S Ag, Pb
Sedimentary types
Copper shale (Kupferschiefer) Cu, S Ag, Zn, Pb, Co, Ni, Cd, Hg
Copper sandstone Cu, S Ag, Co, Ni
Calcrete U U V

lead, and zinc are associated in volcanic- by mechanical movement of fragments under
associated massive sulfide deposits, zinc is gravity, movement as a gas, or diffusion of the
normally more mobile in the surface environ- elements in the form of ions as well as move-
ment than copper and much more so than ment in solution.
lead. Lead is more likely to be concentrated The background levels of an element in
immediately over the deposit, as it is relatively rocks and soils also have to be considered
insoluble, whereas zinc will move or disperse when trying to find secondary dispersion from
from the deposit. This process of movement deposits. All elements are present in every rock
away from the primary source is termed sec- and soil sample; the concentration will depend
ondary dispersion and it can also be effected on the mode of formation of the rock and the