斑岩型铜矿床带条件约束的CSAMT数据精细处理和反演解释

CSAMT data interpretation by fine processing and constraint inversion in the porphyry copper deposit

金属矿产地球物理资料的反演中,数据的自动反演往往会出现反演模型与客观地质情况不符的现象,而带已知条件约束的反演,能限定反演模型的埋深、形状、尺寸、物性变化的范围等,使反演的地电模型更切合实际。以可控源音频大地电磁法(CSAMT)在广西某斑岩型铜矿床的应用为例,考虑了CSAMT方法的有效性、分辨率和岩矿石物性及矿床特征等因素,使用浅部已知矿体、围岩等条件反演剖面地电模型,对深部矿体进行了定位和预测,经钻孔工程验证,取得了显著的找矿效果。

In geophysical data inversion of metallic ore deposits, the automatic inversion of data retrieval models often appears to be in?consistent with the objective of geological phenomena. However, the depth, shape, size, range and other changes in the physical prop?erties of the inversion model with known constraints can restrict the inversion model, so that the inversion of geoelectric model can be?come more realistic. In this paper, with the application of the controlled source audio magnetotelluric survey ( CSAMT) in a porphyry copper deposit of Guangxi as an example, the authors, taking into account the validity of the CSAMT method, the resolution and physi?cal properties of rocks and minerals and the deposit characteristics and other factors, utilized the shallow known orebodies and wall rocks to perform inversion of profiling geoelectric model and made positioning and forecasting of deep orebodies. Drilling verification shows that remarkable ore?prospecting results have been achieved.