Study On The Sedimentary Environment And Physicochemical Properties Of Quaternary In Xuzhou City

Quaternary is one of the most recent geological units in the history of the earth's development.Because the Quaternary geology has regional and the sedimentary environment is very complex,the experience gained in one region generally cannot be fully adapted to other regions.So this paper takes the Xuzhou urban area as an example,the geological subregion and stratification of the Quaternary loose strata in the study area has been carried out.And it uses the stratigraphic sequence,Geochemical element analysis and physicochemical properties to invert the sedimentary environment in the study area.We can get some main results of the study :(1)According to the stratigraphic correlation analysis,the study area is divided into 4 types of geological structure zonation by the first class geomorphologic unit and 50 m shallow stratigraphic structure characteristic: low mountain and hilly area,alluvial plain area,fluvial and lacustrine silt deposit area and alluvial plain area.According to the stratified thickness of many boreholes,the soil structure is stratified as follows: Holocene silt layer,Holocene clay layer,Holocene soft soil layer,silt layer in late Pleistocene series,clay layer in late Pleistocene series,ferromanganese nodule clay layer in mid Pleistocene series and gravel clay layer in Early Pleistocene.The distribution map of the thickness isoline of each soil layer is drawn.(2)The paper takes ZKXY as an example,the borehole is divided into seven soil layers.It describes the variation of the macroelement and the microelement in each soil layer.On this basis,according to the variation of element compounds,elements and the ratio between them with drilling depth,it announces the changes of Quaternary paleoclimate,paleosalinity and redox environment in the study area by using the Earth's elemental chemistry method.The results show that the Quaternary sedimentary environment in the study area is a process from hot,humid to cold and dry,and the total salinity is not high.It may be a fluvial or shallow lacustrine environment,the stratigraphic deposits are aerobic and the deposits are shallow.(3)The paper takes the undisturbed soil samples of borehole ZKXY and the remolded soil samples of ZKS as examples.It analys the variation of basic properties(density,moisture content),physical and chemical properties(pH,resistivity,thermal conductivity and chromaticity)of sedimentary soil layer with borehole depth.It is found that the physical and chemical properties of both undisturbed and remolded soilsamples can well reflect the changes of sedimentary environment.The sedimentary environment was revealed by the variation of physical and chemical properties with depth.It shows that the deposit in the study area is continental.The sedimentary facies of Pleistocene and early Holocene were fluvial and lacustrine facies,but the hydrodynamics effect of rivers was poor,and the separation of sediments was poor.In the late Holocene,weathering was the main sedimentary facies and the sorting was good.