地面磁测异常分离及井中磁测处理在大乌苏南沟(M24)研究区的应用研究

Application study on potential field separation of magnetic areal anomaly and three-component treatment in well in Dawusunangou (M24) iron ore area

中文关键词: 磁异常  叠加异常  向上延拓  异常分离

英文关键词: magnetic anomalies  superimposed anomalies  upward continuation  anomalies separation

中文摘要:

      大乌苏南沟(M24)研究区位于燕山台褶带北缘，受复杂构造控制，矿体群呈多层叠加分布，导致地表磁异常呈现多源叠加特征，严重制约深部矿体识别与定位。本研究针对叠加磁异常分离难题，以地面高精度磁测数据为基础，结合井中三分量磁测技术，通过化极、向上延拓(100 m、200 m、500 m及 1000 m)及反演分析，实现了垂向叠加异常的逐层分离，揭示了不同空间矿体分布特征。研究通过化极处理消除斜磁化影响，采用向上延拓方法压制浅部干扰，分离出浅部铁磷矿体群(②号)、中深部钒钛磁铁矿体(①号 Fe1)及深部辉石角闪岩型超贫铁矿体(③号)。结果显示:①号 Fe1矿体走向长度达 1200 m，倾向延伸 1800 m，平均厚度 180 m，顶部埋深 770 m，钻孔验证误差小于 6%；②号矿体顶部埋深约 200 m，叠加异常强度 3000～6000 nT；③号矿体埋深 593 m以下，水平模差矢量特征指示其侧向延伸潜力。井中三分量磁测数据进一步验证了矿体产状与空间展布规律，水平模差分析表明主矿体向东、向西延伸趋势显著。本研究将地面磁测异常分离与井中磁测三维解析结合，解决了复杂构造区多层叠加磁异常识别难题，定位精度提升约 30%，勘探深度突破 1500 m。成果为燕山地区深部隐伏铁矿勘查提供了可推广的方法体系，对同类矿区资源评价与开发具有重要实践意义。

英文摘要:

      The M24 study area in the Dawusunangou is located on the northern margin of the Yanshan Fold-Thrust Belt. Controlled by complex structures, the orebody groups are distributed in multiple layers, resulting in thesurface magnetic anomalies showing multi-source superimposition characteristics, which seriously restricts theidentification and location of deep orebodies. This study, aiming at the problem of separating superimposed mag-netic anomalies, based on high-precision ground magnetic survey data and combined with in-bore three-component magnetic survey technology, achieved the layer-by-layer separation of vertically superimposed anoma-lies through pole transformation, upward continuation (100 m, 200 m, 500 m, and 1000 m), and inversion analysis,revealing the distribution characteristics of orebodies in different spaces. By pole transformation to eliminate the in-fluence of inclined magnetization and using upward continuation to suppress shallow interference, the shallow iron-phosphorus orebody group (No. 2), the medium-deep vanadium-titanium magnetite orebody (No. 1 Fe1), and thedeep pyroxene amphibolite-type super-poor iron orebody (No. 3) were separated. The results show that the No. 1Fe1 orebody has a strike length of 1200 m, a dip extension of 1800 m, an average thickness of 180 m, and a topburial depth of 770 m, with a verification error of less than 6% from drilling. The top burial depth of the No. 2orebody is about 200 m, and the superimposed anomaly intensity is 3000-6000 nT. The No. 3 orebody is burieddeeper than 593 m, and the horizontal modulus difference vector characteristics indicate its lateral extension poten-tial. The in-bore three-component magnetic survey data further verified the orebody occurrence and spatial distri-bution patterns. The horizontal modulus difference analysis indicated a significant eastward and westward extensiontrend of the main orebody. This study combined the separation of ground magnetic anomalies with the three-dimensional analysis of in-bore magnetic survey data, solving the problem of identifying multi-layer superimposedmagnetic anomalies in complex structural areas, improving the positioning accuracy by about 30%, and breakingthrough the exploration depth of 1500 m. The results provide a replicable method system for the exploration of deepconcealed iron ore in the Yanshan area and have important practical significance for the resource evaluation and de-velopment of similar mining areas.