Size Frequency Distribution of Quartz Sand Particles in Untransported Sediments: Its Significance

The arithmatic probability plots of Size Frequency Distribution (SFD) of untransported in-situ quartz sand accumulations (herein called the 'in-situ sediment'), at the top, slope and foot of a quartzite ridge, generated by thermal disintegration of the source rock (quartzite) show 2 to 4 straight line segments indicating the presence of 2 to 4 log normally distributed sub-populations. The phi standard deviation, σ_φ,increases with decreasing size of the sub-populations indicating a smaller size-spread in coarser sub-populations and wider size-spread in finer sub-populations. These results are shown to be in cornplete consonance with the modus operandi of thermal disintegration. Sand grains of 1.00 mm and finer sizes are shown to be recalcitrant to thermal disintegration. The semblance in the pattern of SFD curves of in-situ sediment as well as those of detrital sediments reader the reliability of the SFD curves as discriminators of transportational/depositional environments questionable.