Size analysis of fine material and related size-frequency distributions
Krog, Marilyn Kendrick
Rogers, John J. W.
Master of Arts
Four groups of naturally-occurring samples were analyzed for size distributions. Four samples with median sizes in the fine sand division (.2-.06mm) graphically approximated a normal distribution. Six samples with median sizes in the fine sand division approximated a lognormal distribution. All samples with median sizes in the fine silt (.006-.002mm) and clay (less than .002mm) divisions did not approximate either the normal or lognormal distributions. A sample of Town Mountain granite was fractured in the laboratory. The data obtained from the sieve analysis of the material smaller than .420mm graphically approximated a normal distribution. The median size of this sample was in the fine sand division. This experiment demonstrated a possible means of producing the normal distribution in naturally-occurring samples. The relationships between statistical distributions applied in geologic work can be shown graphically and/or mathematically. The relationships between the Poisson and normal distributions and the normal and lognormal distributions have been established in earlier publications. The Poisson distribution can be shown to graphically approximate the lognormal distribution as the mean increases.