滇东地区深层次Pt-Cu-Au矿化异常定量提取与评价

滇东地区是我国Cu-Au-PGE重要的成矿远景区.采用因子分析、地质统计学和多重分形S-A滤波等方法对滇东地区复杂地质背景下的不同层次的Pt-Cu-Au矿化异常进行定量提取与评价.结果表明: (1) 因子分析结果揭示滇东地区存在3种元素组合①Cu-Pd-Co-Pt-V-Cr-Ni、②Sb-As-U-Mo、③Pb-Ag-Zn-W-Sn-As-Au, 它们分别代表了位于扬子地块的二叠纪峨嵋山玄武岩、位于华南褶皱系含碳质的沉积建造和以有色金属矿化为代表的热液矿化元素组合特征; (2) 变差函数分析表明Pt、Cu、Au含量在NE向(9°~18.6°) 上变化最连续, 元素含量变化的最大变程范围约95km; 泛克里格法揭示了Pt、Cu、Au含量在区域上变化具有明显的裂控-岩控特征; (3) 多重分形滤波法则细致地刻画了滇东地区与矿化有关的局部异常特征, 有效地提取了Pt、Cu、Au隐蔽矿化异常信息, 其结果可作为圈定Pt-Cu-Au找矿靶区的重要依据; (4) 不同的数学方法可用以解决不同层次的地质成矿问题, 因子分析和地质统计学等线性方法可研究区域成矿地质背景、揭示成矿元素及其元素组合在区域上的空间变化特征, 而S-A滤波等非线性方法能够有效提取深层次局部矿化异常信息. 

Quantitative Extraction and Estimation of Conceal Mineralization Anomalies of Pt-Cu-Au in Eastern Yunnan Province

Eastern Yunnan area is the important Cu-Au-PGE ore-forming perspective area in China.The factor analysis, geostatistics and multifractal S-A filtering method are applied in this paper to quantitatively extract and estimate the Pt-Cu-Au mineralization anomalies from the complicated geological background.The research shows that: (1) the results of factor analysis illustrate that there are three element associations existing in eastern Yunnan area: factor Ⅰ (Cu-Pd-Co-Pt-V-Cr-Ni), which characterizes the element association of the Permian Er'meishan basalt occurred in the Yangtz block, Similarly; factor Ⅱ (Sb-As-U-Mo), which characterizes the carbonaceous sediment formation occurred in the South China fold system and factor Ⅲ (Pb-Ag-Zn-W-Zn-As-Au), which represents the hydrothermal mineralization with the base metal mineralization as the typification; (2) the semivariation analysis illustrates that the concentrations of Pt, Cu and Au are continuous in NE trend (9°-18.6°) and the maximal ranges are about 95km.The geochemical maps obtained by the universal Kringing imply that the concentration distributions of Pt, Cu and Au are mainly controlled by the faults and magmatism; (3) the multifractal S-A filtering method characterizes the detailed information of local mineralization and extracts the conceal mineralization information.The anomaly maps delineated by the S-A method may provide important evidence for Pt-Cu-Au targeting; (4) different geological and ore-forming problems can be solved by different geomathematic methods.The linear geomathematic methods such as the factor analysis and geostatistics can be used to explore the regional ore-forming background and the regional spatial variability of the ore-forming elements and the element associations, while the nonlinear geomathematic methods such as S-A method are efficient in extracting the local ore-forming information.These methods are of benefit to the concealed ore-forming anomaly information extraction.