Beijing Changping Quaternary Sediments Susceptibility, Color Characteristics And Environmental Significance

With conomic development，both global and regional environmentalissues are increasingly prominent. It has aroused wide attention of allsocial sectors, which makes the global change research become thehotspot and focus of earth science research. In the past Environmentproblems are one important components of the global change. Theresearch and regional global changes for the past play an important role inforecasting the abrupt change of regional or global climate.Changping Basin located at west of Beijing, borehole core positionhad been taken in the center of basin area, it is the transitional zonebetween mountains and plains, is also the piedmont catchment area, soclimate and environment change information of the drilling record in thearea is very representative for the ancient climate environment. The basinborehole core high-density sampling and ancient geomagnetic, magneticsusceptibility, chroma, particle size comparison and analysis of the dataeach other, and finally obtain the following several conclusions：(1) First through borehole core measure, get the core ancientgeomagnetic polarity column, and through mutual contrast of the palemagnetic timeline with standard, loess geologic strata and in the samearea formation time, borehole core deep about150m formed in1.07Ma B.P. or so, B/M line in134.2m or so, time is about0.78Ma B.P., duringthe short term polarity events have there.(2) By the high density sampling and measurement, getting the highresolution magnetic susceptibility, particle size and color change ratesequence, then through mutual contrast analysising the magneticsusceptibility and particle size, magnetic susceptibility and mediandiameter appear peak, sample size is mainly made by coarse particlecomposition, concluding that the power of water is caused bystrengthening, and combined with Beijing at the East Asia Monsoonregion, and concludes that the particle size can be instructed to change ofeast Asian summer monsoon intensity.(3) Sampling through follow the certain step length. Then researchingthe chromaticity, the magnetic susceptibility gradually heatingexperiment and analysis for different depth has difference depth leadingmagnetic mineral, and can instruct the turning point of the change ofdifferent sedimentary environment, the L*of chromaticity value may beindicated organic matter and carbonate content changes in the sediment;the a*of chromaticity value in the sample instructions relatively stableferromagnetism mineral content changes; the b*of chromaticity valueinstructions unstable ferromagnetism mineral content changes. (4) Combined with time data and chroma, magnetic susceptibility,particle size and get paleoclimate information of the drilling:1100~800Ka B.P. is mainly cool and there is a small heating between them,800~600Ka B.P. cool and warm alternate in temperature,600~400KaB.P. is priority to hot and humid climate,400~200Ka B.P. is priority tocold and dry climate,200~0Ka B.P. is priority to cool climate alternatefluctuation.(5) From mutual comparative analysis of magnetic susceptibility,chroma and particle size and itself fluctuations, can use them asenvironment change alternative index to research that could be a goodshow environmental change status of area range and with the globalchange response.