基于多元信息约束的隐伏矽卡岩型铁矿床的定位——以云南北衙金矿区红泥塘矿段为例

矽卡岩型矿床是云南北衙金多金属矿区的一种主要矿床类型,受岩体、构造及层位等控制,其有利找矿空间为中酸性岩体与碳酸盐岩的接触带.以岩石物性为纽带,实现目标地质体与地球物理场的转换,提取有效信息.接触带中低电阻率、岩体的低密度性、铁矿的高磁性和高极化率等都是矽卡型铁矿床的特有地球物理属性.通过地质地球物理等多元信息的层层约束,解析不同级次的成矿要素问题,实现对隐伏矽卡岩型铁矿床的定位,建立地球物理勘探模式,并在矿区外围开展方法有效性的验证,取得了良好的勘探效果,提出一套适应于北衙地区及类似成矿地质背景下的隐伏矽卡岩型铁矿床定位预测方法.

Locating of the concealed skarn iron ore deposit based on multivariate information constraints: a case study of the Beiya gold mine in Yunnan province

Skarn deposits are dominant in the gold polymetallic ore mines of Beiya, Yunnan. Controlled by their porphyry, structure and strata, their favorite locations for prospecting are contact zones of alkali-rich porphyries and carbonate rocks. Physical characteristics of rocks serve as vital links to realize the interpretation from the target layer to information of the geophysical field, providing data of validity. The skarn deposit has geophysical characteristic of the medium or low resistivity of contact zones, low density of porphyry, high magnetic susceptibility and high polarizability of the iron ore. This study follows multiple laws and principles of geology and geophysics to analyze ore-controlling factors in different stages, accomplishing the positioning of concealed skarn deposits and the establishment of the geophysical exploration model. Good results were obtained by verifying the validity of the method on periphery of the mining area. This study proposes a locating and calculating method in prospecting for iron ore deposits of the concealed skarn type which can be applied to the Beiya area and other similar geological settings of ore-forming processes.