“三江”地区北段区域地球化学元素组合异常提取及其找矿意义

The extraction of regional geochemical element composite anomalies in northern Sanjiang region and its prospecting significance

由于地球化学元素携带了某种矿化信息,因此元素地球化学异常往往是指示矿床存在的一种直接标志。随着勘查地球化学的深入发展,有关矿致地球化学异常圈定方法已成为人们关注的焦点。利用"三江"北段1∶20万地球化学数据,运用R型因子分析,查明该区不同矿化类型的指示元素组合,以因子得分为综合指标,采用泛克里格剩余值圈定地球化学异常。结果得到2种元素组合:Ag-Zn-Pb-Sb-Bi组合(与热液型铅锌银矿床有关)和Mo-Cu组合(与斑岩型钼矿床有关)。圈定的组合异常与已知的矿床点在空间上具有很好的对应关系,说明利用R型因子分析与泛克里格法相结合圈定元素组合异常的方法能够较好地确认地球化学元素组合异常,并提示异常与矿化类型之间密切相关的规律性,为"三江"北段地区找矿提供信息。

As geochemical elements carry some mineralization information,geochemical anomalies of elements can frequently serve as prospecting criteria.With the deep development of exploration geochemistry,the geochemical anomaly evaluation has become the focus of the attention.Using the 1∶200 000 geochemical data of northern Sanjiang region,the authors determined indicator elements composite anomalies of different mineralization types through the R type factor analysis.On the basis of the factor scores as comprehensive indices,the universal kriging residual value was applied to delineate geochemical anomalies.The results show that there exist two types of element assemblages,i.e.,the Ag-Zn-Pb-Sb-Bi element assemblage associated with hydrothermal Ag and Pb-Zn sulfide deposits,and the Mo-Cu element assemblage associated with porphyry Mo deposits.These two types of composite anomalies are consistent with the known deposits in spatial distribution.It is shown that this method can reveal the regularity governing the close relationship between composite anomalies of geochemical elements and mineralization types,thus providing new information for mineral prospecting in northern Sanjiang region.