Mathematical approach to sedimentary component partitioning of polymodal sediments and its applications

Most continental sediments are composed of overlapped components, whose grain-size follows a type of distribution function. The components and the function type of a sample are determined on frequency and cumulative curves of grain-size distribution so as to designate the function formula. The function parameters can be estimated by fit ting designated function to measured grain-sized data of the sample, which simultaneously achieves numerical partitioning of the components. Genetic analysis of hydraulic and aeolian sediments demonstrates the following environmental impli cations. Fluvial sediment is composed of isolated saltation and suspension component. The sediment in drainage closed lakes is dominated by suspension silt-clay component, with little portion of saltatory sand. Fine sand conponent makes up a majority of desert sand overlapped with small portion of fine dust. Loess is composed of overlapped short-suspending silt component and long-suspension fine component. Long-suspension fine dust is the unique component of deep-sea aeo lian sediment. The fine component shows constant grain-size distribution and genetic connection from desert sand, loess of Northern China to Northern Pacific Ocean, which is transported mainly by westerly stream and dispersed in whole stratosphere to form the background dust.