摘要:
为总结新疆东天山地区与基性 超基性岩体有关的岩浆型硫化物铜镍矿床地球物理特征(电性),在天宇铜镍矿区开展了TEM方法试验研究,通过TEM试验数据,初步总结了地面瞬变电磁法TEM响应、时间常数、电阻率等参数在矿体、断裂、岩体等地质体的特征规律. 试验结果表明,硫化物铜镍矿体的TEM响应曲线晚期衰减缓慢,双对数坐标下,斜率约为1.3~1.5,平均视时间常数约为0.5 ms,背景地层TEM曲线晚期衰减较快,斜率约为2.7,平均视时间常数约为0.23 ms. 反演电阻率图中含矿岩体呈明显低阻反应,电阻率低于200Ω·m,背景地层呈高阻,反演电阻率值大于500Ω·m,断裂分布在高低阻过渡带上. 瞬变电磁法在硫化物铜镍矿床应用效果良好,能够为该种类型矿床的勘查提供一定的参考.
Abstract:
Transient Electromagnetic Method ( TEM) exploration was carried out in the Tianyu Cu-Ni deposit of eastern Xinjiang to sum up the geophysical characteristics of magmatic sulfide Cu-Ni deposits related to mafic and ultramafic rock bodies. In this paper, the characteristics of TEM response, time constant and resistivity for orebody, fracture and rock body are summed up from in-loop and borehole TEM data. Experiments show that the decay curves of the orebody decay slowly and the gradient of the late channels is about 1. 3~1.5 at double logarithmic coordinate, with its apparent time constant being about 0.5ms. The TEM response of background decays is quicker than that of the orebody with its gradient being about 2.7 and its apparent time constant being about 0.23 ms. The apparent re-sistivity of the orebody from the inversion data is below 200 Ω·m, while that of the background is higher than 500 Ω·m. Fractures are distributed in the transition zone of high resistivity and low resistivity. The application effect of the TEM is good in the sulfide Cu-Ni deposit, and can provide some reference for exploration of the same type deposits.
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