低温超导瞬变电磁法在内蒙古四子王旗地质勘探中的应用

瞬变电磁法（transient electromagnetic method，TEM）是金属矿探查的有效手段。超导瞬变电磁法采用高灵敏度低温超导量子干涉器件（superconducting quantum interference device，SQUID）直接接收瞬变电磁二次场，具有本征噪声低（5~7 fT/√Hz）和带宽大（>200 kHz）等特点，勘探浅层分辨率高、探测深度大，优势明显。本文将SQUID系统与商用EM67系统进行了异常环对比实验，验证了以SQUID代替感应线圈作为接收装置的优势与实用性；将该方法应用于内蒙古四子王旗大井坡北部区域的电磁勘探工作，获取了高质量探测数据，反演结果显示浅层和中深层（> 2 000 m）为连续性低阻层；在已有地质资料和物探资料的基础上，结合反演结果可知，测线附近浅层500 m存在北东向断裂带，并推断深部2 000 m处分布着同向断裂带。

Application of Low Temperature TEM to Geological Exploration in Siziwangqi,Inner Mongolia

Transient electromagnetic method (TEM) is widely used in metal mine exploration. Based on the new receiving technology of SQUID (superconducting quantum interference device), the TEM has the advantages of low intrinsic noise (5~7 fT/√Hz) and large bandwidth (>200 kHz). As an important mineral reserve, Siziwangqi in Inner Mongolia is rich in mineral resources. The reliability of SQUID instead of induction coil was verified by comparing the experimental results of the anomalous rings obtained by superconducting receiving system and EM67 TEM instrument. The superconducting TEM method was applied to the northern area of Dajingpo, Siziwangqi, Inner Mongolia. The underground anomalous response information in shallow and deep layers (>2 000 m) was obtained to deduce a continuous low resistivity layer. Combined with the existing geological and geophysical data, the inversion results effectively reveal a north-east trending fault zone at 500 m in the shallow layer near the survey line, and then infer that there is a similar trending fault zone at 2 000 m in the deep layer.