The basis for, and use of, fine grain size parameters for inference of paleoflow speeds is reviewed here. The basis resides in data on deposited sediment taken in conjunction with flow speed measurements in the field, experimental data on suspended sediment transport and deposition, and theoretical treatments of the generation of size distributions of deposits from suspension controlled by particle settling velocity and flow speed. In the deep sea, sorting events occur under resuspension/deposition events in benthic storms. At flow speeds below 10 - 15 cm s(-1), size in the noncohesive "sortable silt'' ( 10 - 63 mm) range is controlled by selective deposition, whereas above that range, removal of finer material by winnowing also plays a role. The best... |