基于证据权重法的沱沱河地区铅锌银矿成矿预测

Lead-zinc-silver metallogenic prediction based on GIS in Tuotuo River region,Qinghai,China

在总结三江北段沱沱河地区成矿规律的基础上,通过GIS平台提取地层、构造、岩浆岩、重力、航磁、化探、遥感异常多元地质找矿信息,建立沱沱河地区铅锌银矿的预测模型,采用MRAS系统中的证据权模块进行预测,对有利成矿区进行圈定。根据单元网格后验概率值的大小划分了3级成矿远景区,共圈定了6个Ⅰ级、7个Ⅱ级和9个Ⅲ级成矿远景区。预测结果表明,83%的已知矿床(点)位于预测的成矿远景区内。除了包含已知矿床(点)的预测区外,沱沱河地区尚有4个Ⅰ级、5个Ⅱ级和4个Ⅲ级远景区目前仍未发现铅锌银矿床(点)。由于这些远景区与已知矿床(点)具有相似的成矿条件,有望实现重大找矿突破,应在今后的勘探工作中得到足够的重视。

Tuotuo River region lies in one of the most important metallogenic belts in China—northwestern Sanjiang metallogenic belt. In this research,multi-source data sets including geological,geochemical,geophysical,and remotely sensed images were integrated for mineral potential analysis with GIS technology. Under the guidance of regional metallogenic features and deposit-forming geologic anomaly theories,evidential layers were obtained from these sets,which were combined to calculate weight for each layer and to identify the posterior probabilities for unit cells of the study area with Weights of Evidence module of the application MRAS. As the results,six level Ⅰ,seven level Ⅱ and nine level Ⅲ lead-zinc-silver prospective belts were delineated with 83% of known mineral deposits among them. Because of the belts＇ similar metallogenic condition with known mineral deposits,they form the most promising zones for considerably attractive new occurrences of mineral deposits,deserving more and adequate attention in future exploration.