甘肃庄浪全新世黄土-古土壤序列元素分布特征及意义

Element distributions of the Zhuanglang Holocene loess-paleosol sequence,Gansu Province and its significance

通过对渭河上游XJN全新世剖面的Fe、Al、Si、K、Ca、Mg、Na、Ti和Sr元素含量的分析,发现这些元素的分布与气候密切相关。在剖面中表现为:迁移序列是Ca>Sr>Na>Mg,Fe、Al、Si、K和Ti则相对富集;Ca-Sr关系呈两段式分布,指示全新世早期的一次环境变化;Ki残积系数增大,Ca/Mg比值减小,指示化学风化作用增强。

A Holocene loess-paleosol sequence was found at Xujianian, Zhuanglang County, Gansu Province. Detailed studies on distributions of Fe, Al, Si, K, Ca, Mg, Na, Ti and Sr show that the variation of major element contents in the profile has a good relationship with climate change. The migration capability is as follows： Ca 〉 Sr 〉 Mg 〉 Na. Fe, Al, Si, K and Ti are relatively enriched. The bifid distribution of Ca-Sr implies the variation of environment in the early Holocene. Eluvial coefficient Ki and Ca/Mg ratio can be used as climatic proxies. Ki increase and Ca/Mg ratio decrease indicate increasing of intensity of chemical weathering.