第二深度空间矿产资源探查理念与电磁法找矿实践

我国第一深度空间(0~500 m)矿产资源量已不能满足国家战略需求, 基于我国深部矿产资源形成的空间和条件的优越性及复杂性, 提出了第二深度空间(500~2000 m)探查大型与超大型矿产资源的科学理念.本文通过两个电磁探测实例, 论证这一理念的正确性.首先, 分析了近源电磁探测和基于飞行平台的电磁探测新方法, 以及噪声去除、反演成像和综合解释等精细数据处理技术.利用近年来新发展的短偏移距瞬变电磁法, 在河北围场铜多金属矿区进行了示范探测, 圈定6处深部矿化异常, 全部得到钻孔验证; 采用可控源音频大地电磁法, 在山东省胶东金矿区精细刻画出深部构造, 并圈定了有利赋矿部位, 揭示了焦家、马塘、寺庄等独立分布的金矿床, 其主矿体均在第二深度找矿空间相互连接, 实际属于同一金矿床, 是世界罕见的超巨型金矿床.两个地球物理探测成果, 是第二深度空间矿产资源成矿理论和找矿实践的有效范例.

Theory on exploring mineral resources in the second deep space and practices with electromagnetic method

The mineral resources buried within the first deep space (0~500 m) in China cannot meet the national strategical requirement. As there is great potential of deep-seated mineral resources in China, the new scientific concept to explore large or ultra-large mineral resources in the second deep space (500~2000 m). This paper validates this scientific concept through two field examples implemented with electromagnetic method. First, high-resolution geophysical techniques, such as the near-source electromagnetic method, flight platform-based detection, noise removal, inversion or imaging method, and comprehensive interpretation, are analyzed. The authors conducted the copper polymetallic mine exploration by using the newly developed SOTEM method in Weichang deposit, Hebei province. 6 deep-seated mineralization abnormalities were revealed and were verified by subsequent drillings. Furthermore, based on a CSAMT survey, the deep structure and potential mining site are delineated in Jiaodong Peninsula. It is found that the independently distributed gold deposits such as Jiaojia, Matang, and Sizhuang, are connected in the second deep space, belong to the same gold deposit and thus become a rare supergiant gold deposit. Both two examples strongly support theory on mineralization and exploring mineral resources in the second deep space.