地磁异常数据处理技术在低纬度地区的应用研究——以柬埔寨王国Mesam金矿为例北大核心CSCD

柬埔寨王国位于低纬度地区,地质勘查程度较低,地面高精度磁测技术能够快速获取磁异常信息,进行找矿评价。在低纬度地区磁化方向主要以水平磁化为主,磁性体产生的磁异常以负磁异常为主。本文通过对柬埔寨王国Mesam金矿磁测数据进行倒相180°、化赤和低纬度化极处理对比,认为三种处理方法得到的结果都能够完整地反映磁场分布特点,在不能忽略剩磁影响的低纬度地区对实测数据进行低纬度化极后再进行解释更加贴近真实且细节更加丰富。通过对低纬度化极后的磁异常进行水平总梯度模和小波多尺度分解计算等位场异常处理,认为磁异常水平总梯度模计算能够较好地反映深部地质体的边界范围,小波多尺度分解计算能够提取特定深度地质体的空间信息,在该区选取的磁异常处理技术是有效的,为进一步扩大该金矿区远景储量提供了新的思路。

Application of data processing techniques of geomagnetic anomalies in low latitudes: A case study of the Mesan gold mine in Kingdom of Cambodia

Kingdom of Cambodia is in low latitudes with poor geological exploration. In such a case, high-precision ground magnetic survey technology can quickly obtain data of geomagnetic anomalies which can be used in ore prospecting evaluation. In low latitudes, the horizontal magnetization dominates the magnetization direction, and the magnetic anomalies generated by magnetic bodies are mainly negative values. In this paper, the magnetic survey data of the Mesan gold deposit of Cambodia ore are processed by phase reversal, reduction to the equator, low latitudes reduction to the pole, respectively. Results for the three methods can fully reflect the distribution of the geomagnetic field, and the data processing by reduction to the pole in low latitudes is closer to reality and reveals more details. The field anomalies processed by low latitudes reduction to the pole are then calculated by the horizontal total gradient amplitude and wavelet multi-scale decomposition. The former can well display the boundaries of deep geological bodies, and the latter can extract spatial information of geological bodies at specific depths. The processing technologies of magnetic anomalies used in this study area are effective, which provides a new thought for the effort of further expanding prospective reserves.