新疆昭苏黄土剖面色度变化特征及古气候意义

Chroma characteristics in the Zhaosu loess section and its paleoclimatic significance

对受西风影响的伊犁盆地南缘的昭苏波马剖面进行色度指标分析后发现，在黄土堆积期间，亮度L＊在很大程度上受控于颜色分量a＊、b＊，同有机质含量关系密切。在S＊ 中亮度L＊与碳酸钙有较好的相关性，而在L＊中相关性极低。红度a＊受赤铁矿含量的影响最大，其较好的正相关关系可以很好地反映气候变干的过程。而黄度b＊与针铁矿相关性较差，易受到多方面因素的影响，对气候转变的敏感性不高。

Chromatic proxies of loess section at the Zhaosu County in the southern Ili Basin are analyzedin this paper. The findings show that correlation between lightness L＊, to a large extent, controlled by colorcomponents, a＊ and b＊, and it is close to organic content. In the interval S0, lightness L＊ correlates wellwith calcium carbonate, while either none or less relates to that in the interval L1. Redness a＊ is mainlyaffected by hematite content, namely, a＊ value increases with the increase of hematite content, suggestingthat it can well indicate the process of drying. But yellows b＊ has less relation with goethite content, withlower sensitivity to climatic shift due to the effects of several different factors.