白云岩风化剖面的粒度分布、元素迁移及碳同位素特征——以黔北新蒲剖面为例

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 白云岩风化剖面的粒度分布、元素迁移及碳同位素特征——以黔北新蒲剖面为例 DOI: 10.5846/stxb201407201477 作者: 作者单位: 首都师范大学资源环境与旅游学院,首都师范大学资源环境与旅游学院,首都师范大学资源环境与旅游学院,首都师范大学资源环境与旅游学院,首都师范大学资源环境与旅游学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金(41473122, 41073096); 国家重点研究项目(2013CB956702); 中国科学院"百人计划" Grain size distribution, element migration, and stable carbon isotope characteristics of dolomite weathering profiles in Xinpu, North of Guizhou Province Author: Affiliation: Capital Normal University,College of Resource Environment and Tourism,Capital Normal University,College of Resource Environment and Tourism,Capital Normal University,College of Resource Environment and Tourism,Capital Normal University,College of Resource Environment and Tourism,Capital Normal University,College of Resource Environment and Tourism Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:研究了影响喀斯特地区土壤有机碳(SOC)更替的因素及其与元素地球化学行为的关系。选取黔北新蒲地区的两个白云岩风化剖面,以粒度分布、有机碳δ13C和元素质量迁移系数为基础,对该区域红色风化壳中有机碳及δ13C值随深度变化的趋势和元素的地球化学特征进行了探讨。结果显示,该区土壤分级后粉粒(5-50 μm)含量占50%-80%,粘粒次之,砂粒最少;δ13CSOC值介于-26.4‰―-23.6‰,且分级后的土样和原样中δ13C值随着剖面深度的增加均减小,各粒级间差异不明显;草地覆被的剖面中铁、钾、钡、钒和锌表现出一定的富集,钠和钴在风化原岩处有一个富集端点,锰在岩粉处富集,镁、钙则完全迁出土体。而耕地剖面中,钒和锌呈现一定程度富集,铁、钾在岩土界面富集,钴在风化原岩富集,而钡在表层微弱富集。 Abstract:The relation of the vertical distribution and cycle characteristics of soil organic carbon (SOC) with the elements in the soil is an important area of research on the soil geochemical circulation and climate change. At the same time, the distribution characteristics of soil elements can also affect the cycle rate of soil organic carbon. To identify the parameters that may influence the turnover rate of soil organic carbon in karst terrain and their relations with the geochemical behavior of chemical elements, we selected two dolomite weathering profiles for analysis (the surface layer is grass and new cultivated land), which are located in Zunyi, Guizhou Province. On the basis of particle size distribution, of the δ13C value of SOC, and the quality migration coefficient of the elements, we discuss the trends of soil organic carbon and δ13C values with the deepening of the red weathering crust in this area and the geochemical characteristics of the elements. Pearson's correlation coefficients were calculated to quantify the relations. Our results indicated that SOC concentrations in the grass profile decreased with the deepening of soil layers, but in the farmland profile, SOC content of the surface layer increased rapidly at the depth of 25 cm, and then decreased with deepening of the profile. The pH value of the surface layer was acidic in both profiles, and the acidity of the grass profile was stronger than that in the farmland profile. The pH value increased with the deepening of soil layers, but the rising trend of the grass profile was more obvious: Soil grain size fraction showed that the silt fraction (5-50 μm) made up 50%-80% of the soil, whereas the sand fraction was the least prevalent. The share of each particle size varied with the deepening of the profile. By means of mass balance approximation and by selecting Ti as an inactive reference element, we obtained a quality migration coefficient of each relevant element. The results showed that almost all elements in the profile showed a certain degree of loss or enrichment. In the grass profile, Fe, K, Ba, V, and Zn showed some enrichment; Na and Co were enriched in the weathering protolith; Mn was enriched in the dolomite powder. In contrast, Mg and Ca were almost absent in the profile. In the farmland profile, V and Zn showed certain enrichment. Fe and K were enriched at the interface of the soil and dolomite; Co was enriched in the weathering protolith, and Ba showed weak enrichment at the surface. Analysis of the δ13C value of SOC showed that this metric was between -26.4‰ and -23.6‰. The δ13C value of both the original soil samples and the silt fraction samples decreased with increasing profile depth, and there was no obvious difference among soil grain fractions. In the grass profile, δ13C and pH significantly correlated with most elements; SOC correlated negatively with Fe, K, and Li (P < 0.05); the migration of elements in the farmland profile was mainly affected by pH. Among all of the elements, there was a significant relation in both soil profiles.Thus, it is possible that the basement carbonate in the vertical direction is inhomogeneous in the Xinpu region, and the local hydrogeological conditions have some influence on the distribution of soil particles. The distribution and migration of elements in the profile are related to soil pH, SOC, and clay content in a soil-forming process; there is also a good covariant relation among the elements. 参考文献 相似文献 引证文献