Page 175 - Introduction to Mineral Exploration

158 C.J. MOON

TABLE 8.2 Background concentration of trace elements and utility in geochemical exploration. (Largely after
Rose et al. 1979, Levinson 1980.)
Element Typical Enriched Surficial mobility Use in exploration
background lithologies
concentration
in soils (ppm)
Antimony 1 Low Pathfinder
Arsenic 10 Ironstones Mobile; Fe Pathfinder
scavenged especially for Au
Barium 300 Sandstones Low often barite Panned concen-
trations in VMS
search
Beryllium 500 ppb Granites High if not in beryl Occasional use
Boron 30 Granites Moderate For borates
Bismuth 500 ppb Granites Low
Cadmium 100 ppb Black shales High Zn deposits
Chromium 45 Ultramafics Low Chromite in panned
concs.
Cobalt 10 Ultramafics Moderate Mn Widely used
scavenged
Copper 15 Basic igneous pH > 5 low, else Most surveys
moderate
Fluorine 300 Alkaline igneous High F deposits
Gold 1 ppb Black shales Low Gold deposits
Lead 15 Sandstones Low Wide use
Lithium 20 Granites Moderate Tin deposits
Manganese 300 Volcanics Moderate, high at Scavenges Co, Zn,
acid pH Ag
Mercury 50 ppb High Wide use as
pathfinder
Molydenum 3 Black shale Moderate to high Wide use
pH > 10
Nickel 17 Ultramafics Low, scavenged Wide use
Platinum 1 ppb Ultramafics Very low Difficult to
determine
Rare earths La 30 Beach sands Very low
Selenium 300 ppb Black shales High Little use
Silver 100 ppb? High; Mn scavenged Difficult to use
Tellurium 10 ppb Acid intrusives Low Difficult to use
Thallium 200 ppb? Low Epithermal Au
Tin 10 Granites Very low Panned concentrates
Tungsten 1 Granites Very low Scheelite fluoresces
in UV
Uranium 1 Phosphorites Very high; organic Determine in water
scavenged
Vanadium 55 Ultramafics Moderate? Little use
Zinc 35 Black shales High; scavenged by Most surveys
Mn
Zirconium 270 Alkaline igneous Very low Little use