粤东崩岗侵蚀作用下土壤中Ti-Zr的重分布

Redistribution of Titanium and Zirconium in Collapse Profile from Granite Weathering Crust in the Eastern Guangdong Province

粤东地区分布着大面积的花岗岩风化壳,由其形成的土壤在高温多雨的气候环境下极易发生崩岗等重力侵蚀,引起局部地球化学环境变化。本文探讨了粤东崩岗区不同剖面中的Ti、Zr及有机质的重分布特征及其与有机质的关系;同时分析了不同剖面中Ti、Zr和有机质的含量。结果表明,侵蚀过程中径流对土壤颗粒的分选作用十分明显,搬运的崩落物离崩口愈远,其Ti、Zr含量愈高,Ti/Zr比值愈大;Ti、Zr含量在崩落物形成的剖面(HJ2)中与有机质呈明显的正相关,表明Ti、Zr迁移不仅与径流分选作用有关,可能也与有机质的络合作用有关。崩壁剖面(HJ1)中Ti/Zr随深度的加大,整体上呈逐渐增加的趋势,Ti、Zr的分布与有机质相关性不明显。

Granite weathering crust is widespread in the eastern part of Guangdong Province, soil developed from which is prone to collapse under the meteorological conditions of high temperature and heavy rainfall, which attributes to local varieties of geochemical environment. The aim of the present paper was to study the redistributing features of titanium, zirconium and soil organic matter, as well as to investigate the relationships between contents of titanium and zirconium and organic matter in the two soil profiles. Contents of titanium.zirconium and organic matter in the two profiles have also been analyzed. The results show that detachment of soil particle is significant in the process of soil erosion. Contents of titanium and zirconium and the ratio of Ti/Zr increase with the distances increasing from the crumble mouth to the alluvial fan. Good correlation coefficients is found between contents of titanium and zirconium and content of organic matter in the slope （HJ2 profile）, indicating that adsorption probably existed between titanium-zirconium and organic matter in the course of soil transportation. These results suggest that mobilie of titanium and zirconium is related to detachment of soil particle and adsorption of organic matter. The ratio of Ti/Zr gradually increased as the depth increasing in the profile of HJ1, is no obvious correlation between the contents of titanium and zirconium and that of organic matter in the profile of HJ1.