Advances in soil gas geochemical exploration for natural resources: Some current examples and practices

Abstract

Field studies have demonstrated that gas anomalies are found over buried mineral deposits. Abnormally high concentrations of sulfur gases and carbon dioxide and abnormally low concentrations of oxygen are commonly found over sulfide ore deposits. Helium anomalies are commonly associated with uranium deposits and geothermal areas. Helium and hydrocarbon gas anomalies have been detected over oil and gas deposits. Gases are sampled by extracting them from the pore space of soil, by degassing soil or rock, or by adsorbing them on artificial collectors. The two most widely used techniques for gas analysis are gas chromatography and mass spectrometry. The detection of gas anomalies at or near the surface may be an effective method to locate buried mineral deposits.

Tabulation of meteorological variables and concentrations of helium, carbon dioxide, oxygen, and nitrogen in soil gases collected regularly from a site at Reston, Virginia, for one year

“…For example, soil moisture and high concentrations of carbon dioxide in a soil gas sample may affect the concentrations of helium measured (Hinkle and Ryder, 1987). Meteorological changes also affect the concentrations of gases measured (Reimer, 1979;McCarthy and Reimer, 1986). Hinkle and Ryder (1988) determined that soil and air temperatures have the greatest affect on concentrations of helium and carbon dioxide in the semi-arid environment of Denver, Colorado.…”

A tabulation of meteorological variables and concentrations of helium, carbon dioxide, oxygen, and nitrogen in soil gases collected regularly from four sites at the Roosevelt Hot Springs Known Geothermal Resources Area, Utah

“…For example, soil moisture and high concentrations of other volatiles present in a soil gas sample may affect the concentrations of the species of interest for exploration (Hinkle and Ryder, 1987). Meteorological changes may also affect the concentrations measured (Hinkle and Ryder, 1988;Reimer, 1979;McCarthy and Reimer, 1986).…”

Meteorological variables and concentrations of helium, carbon dioxide, and oxygen in soil gases collected regularly at a single site for more than a year

“…For example, soil moisture and high concentrations of carbon dioxide in a soil gas sample may affect the concentrations of helium measured (Hinkle and Ryder, 1987). Meteorological changes also affect the concentrations of gases measured (Reimer, 1979;McCarthy and Reimer, 1986). The purpose of this study was to determine which meteorological conditions affect concentrations of helium, carbon dioxide, and oxygen in soil gases in a nonmineralized area.…”