内蒙古维拉斯托地区高精度航磁调查与应用研究

Application Study on High Precision Aeromagnetic Survey in Weilasituo,Inner Mongolia,China

维拉斯托地区位于大兴安岭成矿带内,区域内构造发育丰富,成矿条件优越,继续找矿的潜力巨大.采取向上延拓、小波分析、边界识别等技术对维拉斯托地区的航磁数据进行处理,结合已有地质资料,进一步完善了维拉斯托地区的地质构造,梳理出维拉斯托、拜仁达坝矿床的形成过程.通过航磁异常视磁化率成像反演结果提取出维拉斯托北侧地下的隐伏岩体信息.结果表明:(1)维拉斯托地区的北东向左行剪切性质断裂破碎带整体控制了该区的岩浆活动和矿体运移,同时该断裂带也是东南负磁异常与西北正磁异常之间的磁性过渡带,因此已知矿点与研究区构造分布、磁性强弱分布密切相关.磁异常反演结果显示维拉斯托北侧地下深部可能存在隐伏岩体.据此,本文划分了3处成矿远景区,可为后续找矿工作提供一定参考.(2)向上延拓与小波分析结果显示白音查干-达青牧场断裂(F1)和助力可河断裂(F2)形成时间早、向地下延伸深,是控制维拉斯托地区岩浆活动和构造发育的主断裂.结合倾斜角法等边界识别结果,对研究区内断裂与磁性岩体分布进行了较为精细的拟定,共识别出14条断裂与11处磁性岩体,根据其形成与分布发现维拉斯托是研究区的成矿中心,来自深部的成矿流体经F1与F2在维拉斯托附近上升富集,再由西向东,沿中部北东向断裂破碎带(F3、F4、F5、F6、F7、F10等)运移至拜仁达坝,最终逐渐形成大兴安岭地区两个典型的多金属矿床.

Weilasituo area is located in the metallogenic belt of the Great Xing’an Range(SGXR).With abundant structures and favorable mineralization conditions,there is great potential for continued prospecting.In this paper,aeromagnetic data of Weilasituo area were processed by means of upward continuation,wavelet analysis and boundary recognition techniques.Combined with the existing geological data,the geological structure of Weilasituo area is further improved,and the formation process of Weilasituo and Bairendaba deposit is sorted out.The information of concealed pluton in the north of Weilasituo is extracted from aeromagnetic anomaly apparent magnetic susceptibility imaging inversion results.The results show follows :(1) The NE-to-left shear fracture zone in the central Weilasituo region controls the magmatic activity and ore body migration in the region as a whole.At the same time,the fault zone is also the magnetic transition zone between the negative magnetic anomaly area in the southeast and the positive magnetic anomaly area in the northwest.So the known ore points are closely related to the structure distribution and magnetic strength distribution in the study area.Magnetic anomaly inversion results show that there may be larger hidden ore body deep underground in the north of Weilasituo.Accordingly,in this paper it divides three metallogenic prospect areas,providing certain reference for subsequent prospecting work.(2) The results of upward continuation and wavelet analysis show that Baiyinchagan-Daqingmuchang fault(F1) and Zhulikehe fault(F2) formed early and extended deep underground.It is the main fault controlling magmatic activity and tectonic development in the Weilasituo area.Combined with the results of boundary identification such as tilt angle method,the distribution of fracture and magnetic rock mass in the study area has been elaborated.Fourteen faults and eleven magnetic rocks are identified in the fracture zone.According to its formation and distribution,it is found that Weilasituo is the metallogenic center of the study area.The ore-forming fluids from deep earth rise and enrich near Weilasituo through faults F1 and F2.Then,from west to east,it migrates along the NE fault fracture zone(F3,F4,F5,F6,F7,F10,etc)to Bairendaba.Finally,two typical polymetallic deposits in the Great Xing’an Range(SGXR) area gradually formed.