深海拖曳式瞬变电磁的响应规律  

Responses of the towed transient electromagnetic sounding on deep seafloor

作　　者：周胜[1,2] 席振铢[1] 宋刚 李波 左立标 侯海涛 

机构地区：[1]中南大学地球科学与信息物理学院,湖南长沙410083 [2]长沙五维地科勘查技术有限责任公司,湖南长沙410205 [3]北京先驱高科技开发公司,北京100081

出　　处：《中南大学学报（自然科学版）》2012年第2期605-610,共6页Journal of Central South University:Science and Technology

基　　金："十一五"国家科技支撑计划项目(2006BAB01B07)

摘　　要：通过分析深海堆积型热液硫化矿的电性特征,建立探测深海热液金属硫化物矿床地电模型;运用瞬变电磁全空间理论计算方法,模拟计算深海热液金属硫化物矿床瞬变电磁响应,为设计深海拖曳式瞬变电磁系统提供依据。计算结果表明：深海与无海水情况下的瞬变电磁相比,响应曲线形态变化不大,响应幅值显著增加;拖曳高度严重降低了低阻矿化层的瞬变电磁响应幅值;随着拖曳高度的增加,低阻矿化层的异常响应向后延迟并迅速衰减,当拖曳高度超过50 m时异常响应将难以分辨;在一般情况下,在1-100 ms时窗内可以探测到海底金属硫化矿层引起的异常。By analyzing the electrical characteristics of the deep-sea hydrothermal sulfide ores,an electrical model was established.The transient electromagnetic（TEM） response to the model was computed according to the theory of the TEM response in full-space,which provided a basis for the deep-sea towed TEM system.The results show that the TEM responses to models in deep-sea are similar in the curve shape to that on the earthground,while the amplitude increases significantly.The towing height seriously reduces the TEM response to the mineralized low-resistivity layer.The abnormal response delays and decreases rapidly when the towing height increases.It is difficult to distinguish the response when the height is more than 50 m.Generally,it is possible to distinguish the response to the mineralized low-resistivity layer within 1？100 m window.

关 键 词：拖曳式瞬变电磁 深海热液硫化矿 拖曳高度 观测时窗 

分 类 号：P319.12[天文地球—固体地球物理学]