Geochemical Character And Environmental Significance Of Iron Fractions In Lakes Sediments Of West Inner Mongolia Plateau

Lake sediment is an important part of the geochemical cycle of Fe and other important elements.It is a faithful record of the changes of climate and environment,and rich in information.Fe as redox sensitive elements,plays an important role in the natural cycle of elements,it is of great importance to the redox environment of sediments and plays an important role in early diagenesis.In this paper,four lakes in Inner Mongolia Plateau-Wuliangsuhai,Hulun Lake,Dalinuoer,Daihai as the object of study.Based on the extraction of Fe in sediments,the influencing factors of Fe distribution and its relationship with environmental climate evolution are the main line.We have carried out the study on the distribution characteristics of Fe in lake and sediment in the horizontal and vertical directions,and discussed the relationship between the existence of Fe and the environmental factors.The relationship between the Fe form and the paleoclimatic and paleoenvironment is tentatively discussed.These studies have a certain value in understanding the environmental geochemical significance of different forms of Fe and discussing the interfacial circulation and processes of Fe,P and heavy metals in lake sediments.The main results are as follows:1.A key control factor for the distribution of iron in the surface sediments of four lakes is summarized.It is found that the physical and geographical conditions of the lake basin,the content of different iron forms in the lake,the mineralization of organic matter and the degree of anthropogenic disturbance are important factors that affect the geochemical characteristics of Fe in lacustrine sediments.2.This study gives the dominated morphology of iron in four lake sediments.We explored the contribution of different iron forms to the early diagenesis of iron in lake ecosystems and their differences.At the same time,the change rule of different forms of Fe with the depth of sedimentary column is understood,and we also explain the mutual transformation of different forms of iron.3.Based on the consistency and synchronization of the Fe_mag phase and other substitutes,the response relationship between the Fe_mag form and the climate and climate evolution of Daihai,Hulun and Dalinuoer were tentatively discussed.It is revealed that Fe_mag can record the environmental climate change in lake basin.