成矿元素或元素组在一个地质单元中的富集是成岩和成矿地质过程多阶段作用的产物.基于水系沉积物地球化学数据,主成分分析(principal component analysis,PCA)可识别成矿元素组.奇异值分解(singu-lar value decomposition,SVD)可将成矿元素组主成分得分进一步分解为两个部分:(1)成矿元素组合区域异常分量,能够表征在地壳演化过程中,由各种地质作用(岩浆作用、沉积作用和/或变质作用)形成的有利于成矿的高背景区域;(2)成矿元素组合局部异常分量,能够表征成矿作用引起的,叠加在成矿元素组合区域异常分量之上的成矿元素组合局部异常分量,应用局部异常分量能够识别找矿靶区.本次研究,首先基于国家1∶200 000水系沉积物地球化学数据,应用主成分分析建立不同类型的成矿元素组;其次,利用SVD从成矿元素组的主成分得分中识别出不同类型成矿过程引起的成矿元素组合局部异常分量;最后,应用局部异常分量识别找矿靶区.最终在腾冲地块圈定15处找矿靶区,其中Sn-W找矿靶区8处,Pb-Zn-Ag找矿靶区7处.预测Sn-W潜在资源量915 Mt,Pb-Zn-Ag潜在资源量792 Mt.
Quantitative delineation and evaluation of Sn-W and Pb-Zn polymetallic prospecting target areas in the Tengchong Block by SVD and PCA
Concentration of ore-forming elements or element groups in a geological unit is a result of multistage geological processes.Ore-forming element groups can be identified by principal component analysis(PCA)performed on geochemical mapping data using stream sediments.The principal component scores of the ore-forming element groups can then be used to further identify the regional and local anomalies by singular value decomposition(SVD).Regional anomalies indicate high background regions favorable for mineralization formed under various geological processes(e.g.,magmatism,sedimentism,metamorphism)during crustal evolution,while local anomalies are associated with ore-forming events and can be used to identify ore prospecting targets by superimposition with regional anomalies.In this study,the ore-forming element groups were created using 1∶200000 national-scale geochemical mapping data.In total,15 ore prospecting targets were identified in the Tengchong Block,including eight Sn-W and seven Pb-Zn-Ag prospecting targets.The estimated potential resources of Sn-W are approximately 915 Mt and Pb-Zn-Ag are about 792 Mt.
singular value decomposition(SVD)principal component analysis(PCA)anomalies of ore-forming element groupsgeochemical block conceptSn-Pb-Zn polymetallic depositsTengchong BlockSW China
万方数据
维普
