The Significance and Establishment of Discriminant Function with Grain Size of Stable Lacustrine Sediment and Eolian Loess

Changes in sediment grain-size are mainly controlled by the transporting medium,transporting mode,depositional environment,climate and other factors.Through analyzing characteristic of grain-size,types of sediments can be distinguished,and that characteristic of the sedimentary environment can be concluded,environmental evolution can be interpreted.In this paper,the samples include typical stable lacustrine sediments(282 lacustrine sediment samples from Lop Nur,123 lacustrine sediment samples from Daihai) and typical eolian loess(263 samples from Lanzhou).The grain-size characteristic parameters of these samples are obtained with moment method.This article quantitative analyzes these parameters by means of discriminatory-analytical method.And then obtained discriminant function of stable lacustrine sediments and typical eolian sediments: F(lake,eolian sediment) = 20.363Mz-56.371Sd-67.922Sk +23.516Kg-55.626,if F0,the sediment is stable lacustrine sediment;if F0,the sediment is eolian sediment.This is a good quantitative analysis to the stable lacustrine sediments and eolian sediments of geological history,as well as a basis for distinguish eolian components from the sequence of paleo-lacustrine sediments.And it is significant for the investigation of terrestrial paleoenvironments,drought events and dust-storm events.