关键词: 黄土洼, 坝淤地, 元素, 沉积环境, 相关分析

Abstract: The distribution of elements in deposition profile of dammed silt land can reflect information of depositional environment. It is expected to explore the changes and causes of chemical elements’ content under the effect of water erosion and accumulation in the small watershed area of Loess Plateau，through completely probing and determining the elements in the 4.1m disposition section with fluorescence spectrometer and exerting the related analysis. It turns out that: Si is the most in the dammed silt land，and Al and Ca are second，while Ti is highest among trace elements. The distribution of deposition profile elements in dammed silt land is in three types. Type I，the elements show changes with different beddings and have an obvious alluvium. The relative content of Si has positive correlation to loess silt. It is the typochemical element of loess silt. Type II，the contents of Zr、Cr and Hf respectively reach their maximum at 2.40 m，3.00 m，3.44 m at soil depth，and their contents closely connected not only with the enrichments of organic matters but also clay. While the other elements do not change as the beddings do；Type III，the content of the elements witness the alternation of relative steady phase and phrase of dramatic changes. It found that the depositions in the section at depths from 0.68 m to 0.76 m，0.8 m to 0.96 m，2.42 m to 2.58 m，2.64 m to 2.74 m，3.1 m to 3.26 m correspond to one sand event. The increase of N in profile related to artificial nitrogen fertilizer. Most of elements have strong correlation except Cs and P. The content of Phosphorus is under the double-influence of human and biological factors. And P is mainly affected by atmospheric depositions due to nuclear tests.

Key words: Huangtuwa, dammed silt land, elements, deposition environment, related analysis