Analysis of the giant particle component of the atmosphere over an interior desert basin

An investigation of the mineral constituency of the dust component of the atmospheric aerosol over south-central New Mexico, U.S.A., was conducted from November 1964 to August 1965. The 81 atmospheric dust samples, taken near the surface during this period, were analyzed by dispersion staining microscopy to determine the concentrations of quartz, kaolinite, illite, gypsum, and the carbonate family within the “giant partiele” range. These data reveal that high gypsum concentrations are rare despite proximity to one of the world's largest exposed surface deposits of gypsum, that kaolinite and illite concentrations rise with cold frontal passage from the east if the suspected source region is not snow-covered or water-soaked, and that there exist seasonal variations in concentrations. Geometric mean particle concentrations for the 81 samples were: quartz, eight per cent; kaolinite, eight per cent; illite, five per cent; gypsum, three per cent; and carbonates, ten per cent. Comments are made relative to the possible influence of oceanic and extraterrestrial particles on the observed concentrations.