【摘要】 对晋西北地区表层土壤的物质组成进行研究,可以明确其物质来源、沉积环境及化学风化特征。选择区内表层土壤（深度0、10、20 cm）及其附近的河流沉积物,进行粒度和化学元素组成测试。结果表明:（1）晋西北地区表层土壤粒度组成以黏土和粉沙为主,且有自地表向下粗颗粒组分含量增加的趋势。（2）常量化学元素组成以SiO₂、Al₂O₃、CaO、Fe₂O₃为主,其余元素含量均较低。化学元素组成模式表明研究区内表层土壤物质与黄土高原腹地黄土有相同的物质源区,黄河河流沉积物对其贡献不大。（3）晋西北表层土壤的CIA值为52.70～57.89,平均54.06,说明它们的化学风化程度较低,处于早期的脱Na、Ca阶段。这是由于研究区地理位置比洛川更靠北,气温和降水量均低于洛川,降水量与兰州相差不大,但是年平均气温和年温差比兰州低。该研究明确了晋西北地区表层土壤的物质组成特征,为区域潜在沙漠化危害防治提供了数据支撑。更多还原

【Abstract】 Studies on grain-size and geochemical element composition for topsoil in northwestern Shanxi Province can provide rich information on provenance, sedimentary environment and chemical weathering processes of sediments in the study area. The topsoil（0 cm, 10 cm, 20 cm to the ground surface） and the surrounding fluvial deposits were collected, and their grain-size and geochemical element composition were tested. The results indicated that:（1） the topsoil in northwestern Shanxi Province was mainly composed of clay and silt, and coarse particle contents showed an increasing tendency from the ground surface downward.（2） Major elements were mainly composed of SiO₂, Al₂O₃, CaO, Fe₂O₃, and the contents of other major elements were trace. The composition pattern of major elements suggested that the topsoil in the study region have the same source as the loess in the hinterland of Loess Plateau. The fluvial sediments of Huanghe River contributed much less to the sediments in the study area.（3） CIA values for topsoil in northwestern Shanxi Province varies between 52.70-57.89, and averages 54.06, which demonstrate that the chemical weathering degree of the sediments is very low, and in the early stage of losing Na and Ca. This can attributes to the location of the study area, which situate north of Luochuan and Lanzhou, and the annual mean temperature and precipitation are much lower than in the hinterland of Loess Plateau. The present research clearly demonstrates the composition of topsoil in the northwestern Shanxi Province, and can lay firm foundation to the controlling of potential desertification in the study area.更多还原