| One of the most intuitive field phenomenons of Quaternary Loess Deposits is yellow loess and red ancient soil layers alternated along the ancient soil layer, in the Loess Plateau in China, completing with dozens of loess deposition layers of soil. Numerous studies show that the loess layers were accumulated in the dry and cold ice age, paleosol layers were accumulated in the temperature and humidity of the interglacial period. In the glacial-interglacial cycle process, the air temperature can be followed for large fluctuations. And soil science researches have proved that the soil color is mainly controlled by temperature. Therefore, the color change of loess deposits may be a reflection of temperature change during the Quaternary. Although the characterization of loess color change has been conducted by some research, so far, no one kind of simple and easy method of measuring can do it.Soil color is one of the main morphological characteristics of the soil properties. Color variation in the vertical profiles of soil has a genetic diagnostic significance (Romanov,1998);soil color zoning in space reflects the soil nature was constrained by climatic factors (Xiong Yi,Li Qingkui,1987).Identification with the naked eye has certain subjectivity to the color of soil, so People often use Mount Purcell standard color cards in international.It can distinguish the soil color semi-quantitatively. Our standard color card was been developed in the late 1980s. It was a good application in the national soil survey (Chinese Academy of Sciences, Nanjing Institute of Soil,1989).Xiashu loess generally was developed in the Yangtze River regions, as the edge of the quaternary eolian accumulation phase. Accumulation of Xiashu records southward invasion process in the East Asian winter monsoon since the late Pleistocene, and thus it has large geographical characteristics in climate research of a large section East Asia ancient environment. As the warm and humid climate, the difference is not so obvious between the loess-paleosol layers, it is difficult to distinguish accurately the top and bottom lines of the paleosol, it may leads that Different researchers can draw different profiles.This paper attempts to apply the color reflectance method and quantitatively researches Xiashu color variation. Preliminary results show that Xiashu color reflectance parameters can not only quantitatively determine loess soil, but also as a determination of fast, simple and cheap climate proxy.To explore the soil and, the quantitative relationship between its color of quantitative mineral and environmental conditions was started in the 1960s, and researcher mainly focus on exploring the relation between the most common color mineral such as hematite and goethite in the soil, organic matter and the soil color. Some researches found that there were significant positive correlation between soil colors and free iron oxide, organic matter is the most main factor of the darker color in soil, these changes and climate conditions must rely on the chemical weathering and biological weathering under the condition of given climate (Scheffer et al.,1958; Torrent et al.,1983;Singh et al.,1992;Yang et al.,1999). Therefore, through researching the color changes of soil section (such as the loess),we can explore the soil weathering and pedogenesis, understanding paleo-climatology environmental fluctuation. Since the 1980s, researchers have created all sorts of soil color measuring methods and portable program-controlled chroma instruments (Melville M D et al., 1985;Deaton B C et al.,1991;Fernandez R N et al.,1987).However, in recent years, scholars have not given sufficient attention for the relationship between soil color and climate, to date, the studies have not cleared the climate significance of the color of soil (Fernandez RN et al.,1987;Gao Wangyi et al.,1991,1992;Xia Yingfei et al.,,2000).This study comparative analysis used paleoclimate proxy indicators, the quality of magnetic susceptibility,size, major elements and trace elements of geochemistry and soil reflectance of profile, and try to reveal the climate significance of soil reflectance spectra, and show that the feasibility study of the soil reflectance in climate change and look forward that indicators of soil reflectance spectra of Quaternary climate can play a bigger role in the environment and global climate change research.The purpose of thesis is to explore the relationship between color reflectance of Nanjing Xiashu sediment and other indicators of sediment, and discuss principles and feasibility of the color reflectance of sediments as a study parameter of Xiashu. Because of its sensitive to sediments subtle changes, we can also discuss the ancient climatic implications of the Quaternary sediments use the color change of reflectivity of Nanjing Xiashu.Paper applied large amounts of data, we have collected the sample and data from May 2008.We analyzed Xiashu profile of Taishan Village and obtained a lot of data of color reflectance, and also discussed the relationship of the color reflectance, grain size, chemical elements, and the magnetic susceptibility.The first chapter discussed the research progress of Xiashu, including the causes, oxidation, source material, various types of research indicators, but also introduced the principle of spectral color difference meter, current research and application methods of the color reflectance of loess sediment.The second chapter introduced geology and hydrology of the Nanjing Xiashu and described the location and lithology of the profile of Taishan Village.The third chapter introduced the Xiashu sample collection and laboratory analysis methods, that were the determination of respectively reflection spectra, particle size, geochemical elements and magnetic susceptibility.The fourth chapter introduced distribution of the parameters of the color reflectance in soil profile on the Xiashu loess, including the reflectivity distribution of L* (brightness), a* (redness), b* (yellowness).The fifth chapter introduced:(1)Tested the grain size of the soil samples tested, compared to the study between the sample grain size results and color reflectance. The size of loess mainly reflects the environmental information of deposition. In the size measurement the process, we lost most of the source information. Comparative studies showed that there was the small correlation between loess deposition rate of the grain size and sediment color reflectance, and the less (internal) connection.(2)Comparative study of the major elements, trace elements and color reflectance of the loess samples, basically they reflected the same inherent information with color reflectance, and found the color reflectance of loess deposition and loess many elements were in the link.(3)Introduced the relationship of the magnetic susceptibility and color reflectance. Because the soil magnetic susceptibility mainly reflected the change in ferromagnetic materials, Xiashu with stronger oxidation also generated stronger magnetic susceptibility, the change of color reflectance also was closely related to the redox environment of loess accumulation. There were the common features between magnetic susceptibility and color reflectance, and results of the study also found that there was the consistency between the magnetic susceptibility and the color reflectance changes.The sixth chapter introduced that Xiashu loess reflectance parameters can better distinguish the stratigraphic sequence of Xiashu, and which can be sensitive to distinguish different weathering degree of paleosol and soil layer. Color parameters of Xiashu soil were significantly higher than paleosol sequence of the Loess Plateau in central and southern, and part of the Loess Plateau loess layer has reached the value range of paleosol, and it reflected more intense chemical weathering in the subtropical regions.There were good relations between the color parameters and the existing climate proxy indicators, such as magnetic susceptibility, trace elements and Rb/Sr of. It reflected the spectral reflectance method has good potential in the Yangtze River region for palaeoclimate research.The seventh chapter was the conclusion:summarized the thesis of the main conclusions.
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