Grain - size accumulation percentage of the aeolian sands in the past 150 ka in milanggouwan section is mainly characterized by the aeolian palaeo - mobile dune sands , which are composed of majority fine sands and minority very fine sands . there is n ' t almost any silt and clay . those of the fluvial facies , especially the lacustrine facies and palaeosols , are mainly composed of very fine sands and also contain some quantities of silt and clay 米浪溝灣剖面150kabp以來風成砂的粒度累積百分含量以古流動砂丘砂物質為主,其中以細砂含量最高,極細砂為次,幾乎不含粉砂與粘土;河流相、特別是湖沼相與古土壤以極細砂含量占優勢,且具一定含量的粉砂和粘土。