Study Loess Geochemistry And Its Environmental Significance At Late Quaternary In Liaodong Peninsula

Quaternary eolian sediments are significant to the research of quaternary environment because of wide distributivity, deposition of continuity and sensitivity of the global environment change and the paleoclimate evolution reflects. Liaodong peninsula loess, temple island loess, Shandong Peninsula loess and xiashu loess are important parts of the Quaternary eolian sediments.Liaodong peninsula loess is distributed on the land and sea border areas in China and recorded the changes of ancient climate and ancient environment well. This paper took loess major element content, distribution and oxide ratio as main research contents, quantitatively analyzed the major elements, and compared with the contents of trace elements, CaCO3 and organic matter and pH value. Afterwards, climate when loess was forming and ancient environment change are discussed by combining with magnetic susceptibility change, thereby the changes of ancient climate and ancient environment when loess was accumulated in this area are revealed.It is demonstrated from the analysis of the major elements, trace elements, CaCO3 ,pH value and organic matter that these indicators have certain indicating meaning for the changes of ancient climate and ancient environment. The contents of chemical constituents of Liaodong peninsula loess, Loess plateau loess and xiashu loess have little difference, which indicated that the loess is consistent from the perspective of the original materials, and difference of sevral elements was resulted from different climate and environment in the later deposition period.Compared with average UCC value, Na, Ca, Mg, P, Sr and Zn are obviously lost in Zhoujiagou loess, Mn, Ti, Co, Ni, Cr and V are enriched obviously , and other elements changed little. The Zhoujiagou loess not only showed obvious weathering of carbonate mineral, but also silicate minerals, such as anorthose, whose decalcification and Na deprivation process was obvious and depotassication was not obvious. The loess was still in the middle stage of weathering.The performance of migration and accumulation of Zhoujiagou loess was different from Malan and Lishi loess, which showed that climate of Liaodong Peninsula in the late Pleistocene and late Pleistocene Epoch changed significantly, namely that humid climate and environment suddenly turned into cool and dry climate and environment. The comprehensive parameters of oxide ratio indicated that Liaodong Peninsula undergone 3 cycles of climate fluctuations under the total warming trend of the late Pleistocene climate. Above number 6 of layer of gravel, namely from the demarcation line of Lishi and Malan loess to 11m to 10m distance form the earth's surface, the climate was grdually coolling. The climate was the most cold and dry in this stage, wherein, the minimum value of CAI is 59.75. Then, climate was grdually warming from 10m to 5 m, dry and cold at 8m to 7m in short time, and dry and cold at 5m to 2.5m in long time, climate was grdually warming from 2.5m to 1m.Moreover, climate suddenly turned into cold from warm, and gradually turned into warm from cold.