湘江谷地土壤中微量元素铀和钍的含量及分布特征

本研究利用仪器中子活化法对湘江谷地土壤中的天然放射性元素铀和钍进行了测定。文中报道了该地区不同土类和母质土壤及全区土壤中铀和钍的含量及其分布特征。在该区6种主要类型土壤中,铀和钍的含量分布规律基本相同,即山地草甸土>山地黄棕壤>水稻土>红壤>黄壤>紫色土。全区土壤中铀和钍的平均含量分别为4.20ppm和17.0ppm。该值均高于世界土壤中铀和钍的平均含量(2ppm和9ppm)及地壳平均丰度(2.7ppm和9.6ppm),同时也高于我国其它地区。文中还对该区土壤中铀和钍的比值(Th/U)进行了讨论。

CONCENTRATIONS AND DISTRIBUTIONS OF U AND Th IN THE SOILS FROM THE XIANGJIANG VALLEY

The concentrations of U and Th in the Xiangjiang Valley soils were determined by Instrumental Neutron Activation Analysis (INAA). The abundances of U and Th and their distribution characteristics in different great groups of soils and the soils derived from different parent materials are presented. The contents of U and Th in six major soil groups of the area rank as follows: mountain meadow soil>mountain yellow-brown earth>paddy soil>red soil>yellow soil>purple soil. The average contents of U and Th in the whole area are 4.20ppm and 17.0 ppm, respectively. They are much higher than those of the world soil (2ppm and 9ppm) and crustal abundances (2.7ppm and 9.6ppm). The Th/U ratios in the soils of the area were also discussed.