保靖县梅花乡物探异常分析  

Abnormal characteristics analysis of geophysical prospecting of Meihua region in Bojing county

作　　者：杨湘生 

机构地区：[1]湖南省地质工程勘察院,株洲412003

出　　处：《水文地质工程地质》2002年第4期46-49,共4页Hydrogeology & Engineering Geology

摘　　要：梅花乡 ρs 平面图在物探推断的NE向与NW向构造复合区内的异常特征为 ρs 变化率大 ,形成变化率异常区。梅花乡岩溶发育具极不均匀性 ,深部的强岩溶发育段含丰富地下水 ,但 ρs 断面图的异常特征不能显示强岩溶发育段 ,而二次导数断面图Ds 负极值区与高密度电法 ρs 断面图中 ρs 变化率异常区与强岩溶发育段密切相关。综合分析激发极化 ηs曲线、偏离度R曲线、半衰时Ts 曲线的异常特征 ,可以提高岩溶富水性的准确度。分析钻探资料可知 :ρs 变化率异常区即是富水地段 ;强岩溶发育段深度与Ds 负极值区或高密度电法 ρs 变化率异常区推断的深度较为吻合 ;对应含水破碎段ηs>1% ,而由偏离度极小值或半衰时极大值推断的深度与主要含水层的深度有较好的对应关系。The study based on the hypothesis is if a low electrical body is found on the high resistance rocks such as in fracture zone and karst zone,low resistance zone will be demonstrated to be abnormal on a plane,consequently,the rate of ρ _s variation on the plane will be great in combining abnormal zones,such as the compound structure zone.After the geophysical prospecting in Meihua area,the ρ _s plane shows that the ρ _s variation is great in north-east and north-west direction of the compound structure zone,it is an abnormal zone.The development of karst in this area is heterogeneous, The ρ _s section can not show the strong development of karst in depth where the groundwater is rich. But the strong development of karst is closely related to the D _s negative extremum zone of second derivative section and the ρ _s abnormal zone of the high density electrical method at ρ _s section.The accurate judgment of rich water-zone can be greatly enhanced by the general analysis of the abnormal features of induced polarization curve η_s ,deviation degree curve R and half-period curve R .Therefore,conclusions are drawn that ρ _sabnormal zone indicates rich water area, on the other hand,the depth of strong development of karst is very consistent with the depth which is deduced from the D _s negative extremum zone or ρ _s abnormal zone of high density electrical method. At water-contained fracture, η _s>1%. The depth of the main water-contained layers is corresponding with the depth which is deduced from the minimum value of deviation degree or the maximum value of half life.

关 键 词：保靖县 数值处理 偏离度 导数计算 物探 数据处理 地下水 激发极化 

分 类 号：P641.7[天文地球—地质矿产勘探] P631[天文地球—地质学]