中文摘要：

勘查地球化学是地质找矿的一种重要手段,而能否有效地提取地球化学异常决定了化探工作的成败。模糊决策树技术是近年来迅速发展的一种数据挖掘方法,笔者在系统总结前人研究成果的基础上提出了一种简单模糊决策树的思想来提取地球化学异常,以三江南段地区1∶20万水系沉积物测量数据为例验证了该技术在寻找多金属矿方面的可行性。结果表明：该方法提取的地球化学元素组合异常与现有矿点吻合程度好,明显优于使用元素累加和求取异常的做法。模糊决策树技术用于提取地球化学异常不仅具有理论价值,而且对三江南段地区的矿产勘查具有指导意义。

英文摘要：

Geochemical exploration is an important means in geological prospecting,and whether geochemical anomalies can be effectively extracted or not decides the success or failure of this means.Based on a systematic summarization of previous studies,the authors propose an idea of fuzzy decision tree for extracting geochemical anomalies.Exemplified by the data obtained in 1：200000 stream sediment survey of southern Sanjiang region,this paper has validated the feasibility of the technology.Studies show that the composite anomalies of chemical elements coincide well with the known mine sites,and are much better than the anomalies based on element summation.The technique of fuzzy decision tree for extracting geochemical anomalies has not only theoretical value but also practical significance in ore-prospecting work of southern Sanjiang region.