CAJ | 학술논문

从土壤到水系沉积物风化过程中微量元素含量的变化行为对化探异常的圈定和解释具有重要参考价值。以北京西南房山花岗闪长岩体发育的土壤为研究对象，通过盐水及盐酸溶液去除土壤中的活动态微量元素，以模拟含盐水系及酸性水系，实验查明从土壤到水系沉积物风化过程中微量元素的变化行为。实验结果发现从土壤到盐水不溶物再到酸不溶物，花岗岩风化指数（WIG 值）逐渐降低，表明 WIG 是表征其风化程度的良好地球化学指标。样品粒度越细其风化程度越高，热液成矿元素含量从粗粒级到细粒级含量逐渐升高，建议采样粒度为80～100目。
종토양도수계침적물풍화과정중미량원소함량적변화행위대화탐이상적권정화해석구유중요삼고개치。이북경서남방산화강섬장암체발육적토양위연구대상，통과염수급염산용액거제토양중적활동태미량원소，이모의함염수계급산성수계，실험사명종토양도수계침적물풍화과정중미량원소적변화행위。실험결과발현종토양도염수불용물재도산불용물，화강암풍화지수（WIG 치）축점강저，표명 WIG 시표정기풍화정도적량호지구화학지표。양품립도월세기풍화정도월고，열액성광원소함량종조립급도세립급함량축점승고，건의채양립도위80～100목。
Stream sediment is the main medium sampled in the Regional Geochemistry-National Reconnaissance (RGNR)project in China,and soil is the main source of stream sediments.Behaviors of major and trace ele-ments during the weathering from soil to stream sediment have played an important role in delineating and inter-preting the geochemical anomalies.The soil developed over granodiorite in the southwest of Beijing was selected and its insoluble matter from 0.5 mol /L NaCl solution and then from 0.1 mol /L HCl solution was removed se-quentially to simulate the geochemical process from soil to stream sediment.According to the particle size of soil,seven size fractions were meshed from 5 mm to less than 0.154 mm for two soil samples,then its insoluble matter from each size fraction was extracted sequentially from saline to acid solution.The results indicate that the sample mass ratio of soil insoluble matter from saline and acid solution respectively to its soil are all less than 13% and their values of WIG (weathering index of granite)are decreasing clearly from soil to saline insoluble matter and then to acid insoluble matter.This shows WIG is a good geochemical index to describe the sample’s weathering degree during the process from soil to stream sediment (represented by the insoluble matter).Soil and its insoluble matter (or stream sediment)developed over granodiorite have more extensive degrees of weath-ering with finer particle size.Contents of most indicator elements of hydrothermal mineralization are also increas-ing with finer particle size.Samples with particle size of 80 -100 mesh (or 0.2 mm to 0.154 mm)are sugges-ted as the best medium sampled for the geochemical exploration in this region.With respect to the difference of element contents in samples with different particle size,contents of indicator elements of hydrothermal minerali-zation in each size fraction vary unclearly in soil and its insoluble matter.This provides an example to verify the feasibility of collecting different medium (soil or stream sediment)with same size fraction to recognize element anomalies in geochemical exploration.