陕南丹凤茶房村黄土-古土壤剖面色度参数特征

以丹凤县茶房村黄土-古土壤剖面为对象, 研究了该区黄土色度参数的变化规律及其主控因素。结果表明, L*(亮度)在黄土层中出现峰值, a*(红度)、a*/b*(红度/黄度)在古土壤层出现峰值, 色度参数的峰谷变化特征与该区黄土-古土壤地层旋回相吻合。L*(亮度)的变化与有机质含量密切相关;a*(红度)、a*/b*(红度/黄度)的变化则受控于铁氧化物的种类和含量。尽管三者的受控因素不同, 但都与风化成壤强度密切相关, 且与磁化率形成良好的对比, 可作为良好的气候代用指标, 间接地反映该区气候和成壤环境的变化规律。

Chroma Characteristics and Its Significances of the Chafangcun Loess-paleosol Profile in Southeast Shaanxi,China

The chroma and its major controlling factors of the Chafangcun loess-paleosol profile was studied in Danfeng, which is located on the southeast Shaanxi. Results show that lightness, redness and redness/yellowness are significantly different between loess and paleosol layers, with relatively low lightness values and high redness and redness/yellowness values in the paleosol layers. The lightness is strongly linked to the organic matter, By contrast the redness and redness/yellowness are strongly linked to the types(e.g., hematite and goethite)and concentrations of iron oxides. While variations in the lightness,redness and redness/yellowness are controlled by different color materials, these three proxies are closely associated with post-depositional processes such as chemical weathering and pedogenesis. And they are also good comparison between these chromaticity coefficients and magnetic susceptibility. Which indicates that the variation of chromaticity coefficients can indirectly reflect the change of climate and pedogenic environment.