基于证据权模型的宁芜盆地中段玢岩铁矿资源预测  

Mineral Prediction of Porphyrite Iron Ore Deposits in Middle Part of Ning-Wu Basin Based on Weight of Evidence Model

作　　者：赵增玉[1,2] 陈火根[1] 潘懋[2] 贾根[1] 徐士银[1] 张祥云[1] 

机构地区：[1]江苏省地质调查研究院,南京210049 [2]北京大学地球与空间科学学院,北京100871

出　　处：《北京大学学报（自然科学版）》2015年第5期863-870,共8页Acta Scientiarum Naturalium Universitatis Pekinensis

基　　金：江苏1:5万慈湖;柘塘镇;小丹阳;博望镇幅区域地质调查项目(1212011120850)资助

摘　　要：基于证据权模型,对宁芜盆地中段玢岩铁矿进行矿产资源评价。首先,结合研究区的成矿地质背景,提取地层、岩体、构造、物探异常等四大类证据因子。然后,分析各证据因子与铁矿点之间的空间关系,认为大王山旋回火山岩与次火山岩与玢岩铁矿的关系最为密切,是寻找玢岩铁矿的岩石标志,深成侵入体则与铁矿空间上无明显关系,构造、物探异常在空间上与玢岩铁矿也有较大关联。根据计算结果,选取与玢岩铁矿密切相关的大王山旋回火山岩地层、闪长玢岩岩体、各方向(EW,NW,NE)构造缓冲区、航磁异常和布格重力异常七类证据图层。最后,采用证据权模型进行成矿后验概率计算,结合成矿地质背景及物探异常,圈定5个成矿预测区,它们在区域上具明显的NE向展布特征,并且普遍分布与成矿密切相关的闪长玢岩岩体,同时位于航磁高值以及NW向和NE向构造发育密集处。Mineral prediction of porphyrite iron deposits in middle part of Ning-Wu Basin is conducted based on weight of evidence model. Firstly, the geological setting of ore-forming processes is introduced. Four kinds of evidence factors including formations, intrusions, structures and geophysical anomalies are extracted. Then, the spatial relationships between mineral occurs and each evidence factor are discussed. It is suggested that volcanics and subvolcanics in Dawangshan cycle, which are rock indicators of porphyrite iron deposits, have great relation with porphyrite iron deposits. However, plutonic intrusions have no relationship with iron deposits. Structures and geophysical anomalies are also closely related to porphyrite iron deposits. The seven evidence raster layers including Dawangshan Formation, diorite porphyry, buffers of the structure lines with NE, NW and EW trending, aeromagnetic anomalies and Bouguer gravity anomalies are selected after conditional independence test. These evidence factors are all closely related to the porphyrite iron deposits. Finally, metallogenic posterior probabilities are calculated according to weight of evidence model. Five ore-forming prospects with NE trending are indicated based on the geological conditions of metallogenesis. Diorite porphyry is generally distributed in the prospects. Also, the prospects are in the areas with high aeromagnetic value and intensive NW and NE structures.

关 键 词：宁芜盆地 玢岩铁矿 证据权模型 成矿预测 

分 类 号：P618.31[天文地球—矿床学]