粤东花岗岩流域覆盖型风化壳风化特征比较  

Comparison on the weathering characteristics of the alluvium-covered weathering crust for the granite catchments in eastern Guangdong province

作　　者：刘昆[1] 何捷[1] 焦树林[1] 佘建伟[1] 刘尚仁[1] 高全洲[1] 

机构地区：[1]中山大学地理科学与规划学院,广东广州510275

出　　处：《生态环境》2008年第5期1937-1941,共5页Ecology and Environmnet

基　　金：国家自然科学基金项目(40671027);广东省自然科学基金项目(7003669)

摘　　要：为了对比在同种基岩与气候背景下,相邻花岗岩流域风化壳的风化程度,借助粒度组成、pH值和磁化率等实验方法,测定了粤东榕江和漯河流域阶地上发育的冲积物覆盖型风化壳。数据结果说明,螺河流域发育的该类型风化壳的风化程度强于榕江流域阶地上发育的该类型风化壳。粒度组成还表明,两流域该类型风化壳具有在<2μm粒级含量上冲积层大于基座风化壳的特征。两个流域风化壳粒度组成差别的原因是两个流域不同的剥蚀速率,榕江流域剥蚀速率较快。pH值在冲积物覆盖型风化壳剖面上呈现三低两高间隔出现的规律。螺河流域风化壳磁化率低于榕江流域是由局部的地貌条件决定,磁化率在粤东地区该类型风化壳的指示意义不准确。The alluvium-covered weathering crust under study was developed on the terrace base by intensive chemical weathering in the east of Guangdong province. The weathering characteristics of two adjacent alluvium-covered weathering crusts upon catchments are compared, so as to illuminate their differences of weathering stages under the same geological and climatic conditions, by measuring grain size, pH, and magnetic susceptibility. The result shows the weathering degree of the alluvium-covered weathering crust in Luohe River catchment is more intense than that in Rongjiang River catchment. The data of the grain size also shows the characteristics that weathering degree of the crust developed on the alluvium is more intense than that developed on the weathering base crust, especially in the grain size of less than 2 prn. The difference of grain size between the alluvium-covered weathering crusts in the two catchments may be affected by the rate of physical erosion. There are alternate characteristics about pH value in the alluvium-covered weathering crusts. The meanings of the magnetic susceptibility in the alluvium-covered weathering crusts cannot reflect the fact of the weathering degree.

关 键 词：粤东 相邻流域 冲积覆盖型风化壳 粒度组成 PH值 磁化率 

分 类 号：P931[天文地球—自然地理学]