钦杭成矿带南段文地幅水系沉积物地球化学异常识别

Geochemical Anomaly Identification of Stream Sediments of Wendi Sheet in the South Segment of the Qinzhou-Hangzhou Metallogenic Belt

基于野外地质调查工作基础上,应用统计方法和分形方法对文地幅1∶5万水系沉积物地球化学数据进行异常下限的确定,并基于不同异常下限结果绘出异常图,与矿点进行叠合。结果表明,通过常规统计法确定的Au、Ag、Cu、Pb、Zn异常下限分别为1.62 ng/g、0.12 ng/g、22.59μg/g、104.00μg/g、77.73μg/g,分形方法确定的异常下限分别为8 ng/g、0.325 ng/g、220μg/g、460μg/g、2240μg/g。在空间上,应用分形方法圈定的异常与矿点叠合的更好,可以更加有效的降低非矿引起的异常范围,减少徒劳的异常查证,提高了找矿效率。

1∶50000 regional stream sediment geochemical data contain much information of prospecting.Thus,geochemical anomaly identification of stream sediments is very important.Based on the geological survey in the fields,the anomaly lower limit of 1∶50000 regional stream sediment geochemical data of the Wendi Sheet was determined by using statistical methods and fractal methods,then superimposed with the delineation results and mineral occurrence.The research shows that the anomaly lower limits of Au,Ag,Cu,Pb,and Zn are 1.62 ng/g,0.12 ng/g,22.59 μg/g,104.00 μg/g,and 77.73 μg/g respectively by statistical methods,and 8 ng/g,0.325 ng/g,220 μg/g,460 μg/g,and 2240 μg/g respectively by fractal methods.The spatial superposition of the delineation results and mineral occurrence is better by fractal methods.The fractal methods in determining the anomaly lower limit can be more effective in reducing the scope of anomalies caused by non-mineral.It can reduce the useless anomaly inspection and improve the efficiency of prospecting.