矽卡岩矿床岩体形态定量分析及成矿关系——以安徽铜陵凤凰山铜矿床为例

摘要

The shapes of intrusive body and contact zone might influence the formation and distribution of orebodies in skarn deposit. By taking Xinwuli intrusive body in Fenghuangshan copper deposit, Tongling, Anhui, China, as the research object, a new method was used to obtain the quantitative relationship between intrusion morphology and skarn mineralization. The first step of the method was to extract morphological characteristic parameters based on mathematical morphology and Euclidean distance transformation; then the quantitative relationship between the parameters and orebodies was analyzed; finally correlational analyses between the parameters and mineralization indices were conducted. The results show that morphological characteristic parameters can effectively indicate the location of concealed ore bodies in skarn deposit, with the following parts as advantageous positions of skarn mineralization: (1) the parts away from the 1st trend surface in the range from?25 to 50 m; (2) the convex parts about 200 m away from the 2nd trend surface, around which the tangent plane of the intrusive body is approximately consistent with the trend surface; (3) the contact zones with angle between intrusive body original contact surface and trend contact surface ranging from 35° to 70°; (4) the parts with angle between intrusive body original contact surface and regional extruding far crustal stress ranging from 50° to 60°. These knowledge can be applied to more skarn deposits for future mineral exploration.%矽卡岩型矿床矿体的形成和分布主要受岩浆岩的形态及其与围岩的接触带控制.以凤凰山铜矿新屋里岩体为实验对象,运用新方法获得侵入岩岩体形态与矽卡岩矿化的定量关系.首先,基于数学形态学和欧式距离变换,提取岩体三维形态特征参数;然后,分析形态参数和矿体之间的定量关系;最后,进行形态参数和矿化指标之间的相关性分析.结果表明,形态特征参数能有效指示矽卡岩矿床隐伏矿体位置,矿体主要位于:(1)距离一级趋势面?25~50 m的岩体部位;(2)距离二级趋势面200 m附近的外凸部位,附近岩体切平面与趋势面走向一致;(3)岩体原始接触面和趋势接触面之间的夹角为35°~70°的接触带;(4)岩体原始接触面与区域挤压远应力场之间的夹角为50°~60°的岩体部位.这些定量关系可以推广到其他矽卡岩矿床的矿产勘查中.