苗运法, 杨胜利, 卓世新, 孙爱军. 我国西北干旱区现代地表沉积物颜色指标与降水关系[J]. 海洋地质与第四纪地质, 2013, 33(4): 77-85. DOI: 10.3724/SP.J.1140.2013.04077
引用本文: 苗运法, 杨胜利, 卓世新, 孙爱军. 我国西北干旱区现代地表沉积物颜色指标与降水关系[J]. 海洋地质与第四纪地质, 2013, 33(4): 77-85. DOI: 10.3724/SP.J.1140.2013.04077
MIAO YunFa, YANG ShengLi, ZHUO ShiXin, SUN AiJun. RELATIONSHIP BETWEEN THE COLOR OF SURFACE SEDIMENTS AND PRECIPITATION IN ARID NORTHWEST CHINA[J]. Marine Geology & Quaternary Geology, 2013, 33(4): 77-85. DOI: 10.3724/SP.J.1140.2013.04077
Citation: MIAO YunFa, YANG ShengLi, ZHUO ShiXin, SUN AiJun. RELATIONSHIP BETWEEN THE COLOR OF SURFACE SEDIMENTS AND PRECIPITATION IN ARID NORTHWEST CHINA[J]. Marine Geology & Quaternary Geology, 2013, 33(4): 77-85. DOI: 10.3724/SP.J.1140.2013.04077

我国西北干旱区现代地表沉积物颜色指标与降水关系

RELATIONSHIP BETWEEN THE COLOR OF SURFACE SEDIMENTS AND PRECIPITATION IN ARID NORTHWEST CHINA

  • 摘要: 现代沉积物颜色(亮度L*、红度a*和黄度b*)与气候参数(年均温和年降水量)关系是理解地层沉积物颜色指标及其气候意义的关键。但绝大多数研究主要集中在现代土壤及其古土壤序列,基本未涉及到现代河湖相沉积物。首次通过对我国西北干旱区大空间尺度上57个地表沉积物样品的采集分析,用以探讨颜色指标与气候参数之间的关系。结果表明,L*a*b*三组颜色参数变化范围分别为:67.0~80.0,1.2~9.4和7.2~22.1,其中L*a*之间相关性较低(0.29),而a*b*之间相关性良好(0.83)。同时,考虑到采样点远多于气象站(点)数量,二者之间不能进行直接相关,基于海拔与温度之间存在线性关系,技术上将L*a*与对应样点的海拔高度进行相关分析,结果发现它们的相关性很低(分别为0.19和0.23),说明颜色指标与温度之间没有必然联系。同样,基于经纬度变化基本可以和降水量的多寡联系起来,技术上将L*a*与经纬度进行相关,结果发现相关性较好(前者为0.28和0.34,后者为0.55和0.53),表明a*优于L*与降水量之间的联系。通过进一步将气象站点附近的颜色指标进行加权平均,发现L*a*指标与降水量之间存在着较好相关性(分别为0.44和0.55)。另外,研究发现L*与CaCO3含量之间相关性极低,而a*与赤铁矿关系不大。未来我们将进行有机质含量和岩石磁学的测试,以更好地确定颜色指标各自的致色矿物。

     

    Abstract: The relationship between the modern surface sediment color (e.g., L*, a* and b*) and climatic parameters, including mean annual temperature (MAT) and mean annual precipitation (MAP), is the key to understand the past. Many studies on it are mainly focused on the modern soil and the paleosol-loess sediments in or around the Loess Plateau, and little have been devoted to the color of modern fluvial-lacustrine sediments and its relationship with climate. In this paper, we sampled at 57 sites along/around the Tianshan mountain region, very dry place in Xinjiang Area, Northwest China, to measure three parameters of color, the lightness L*, the redness a* and the yellowness b*. The results show that the values of L*, a* and b* are 67.0-80.0, 1.2-9.4 and 7.2-22.1 respectively. The relatively low correlation coefficient between L* and a* probably implicate little relationship between them, while the correlation coefficient between a* and b* is quite high. At the same time, the low correlation coefficient between altitude and either L* or a* probably imply that there is no relationship between the color parameters and MAT. However, the relatively higher correlation coefficient at different latitude means that color parameters are linked with MAP, The values of the coefficient can reach 0.28 and 0.37, 0.55 and 0.53 for L* or a* respectively. Further, we separate all color data into 16 groups in order to compare them with the precipitation records from the meteorological stations along/around the Tianshan region, the correlation index between the L*, a* and MAP are 0.44 and 0.55 respectively. We argue that such high ratios are results of the relationship between the precipitation and the surface sediments color, especially a*. Additionally, due to too low correlation coefficient, we find no relationship between L* and CaCO3 (%) and the same situation may occur between a* and hematite. In the future, we will measure the total organic matters and the rock magnetic parameters in order to make clear what are the coloring matters.

     

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