河南新郑—太康断裂东段土壤气体地球化学特征

Geochemical Characteristics of Soil Gas in the Eastern Section of Xinzheng—Taikang Fault,Henan

土壤气浓度测量能够揭示断裂位置和活动特征。由于河南新郑—太康断裂北西向隐伏断裂带空间定位精度有待提高,以及2016年5月该区出现地下逸出气异常的宏观现象,在太康县西近垂直于断裂走向布设了一条长约13km的NE—NNE走向的地球化学观测剖面,用于分析隐伏断层浅层位置及其与地下逸出气宏观异常的关系。观测结果表明:该剖面的异常段与该区浅层地震勘探显示的断裂带地表出露位置相吻合,其中Rn体积活度和H2、CO2浓度异常揭示出南段有4条断层,北段有2条断层,且均具有高角度特征,南段的CO2浓度异常区与地下逸出气宏观异常位置相符,但代表构造特征的Rn体积活度和H2浓度没有出现异常,认为与构造关系不密切。

Soil gas concentration measurement can reveal fracture location and activity characteristics.In terms of the problem of unobvious surface exposure of the Xinzheng—Taikang NW concealed fault in Henan as well as the phenomenon of the macroscopic anomaly of underground escaping gas in May 2016,an NE—NNE geochemical observation crosssection about 13 km long was set near the west of Taikang,which is vertical to the direction of the fault,and it is used to analyze the relationship between the surface exposure location of concealed fault and the macroscopic anomaly of underground liberated gas.The observation results show that the anomalous section of the cross-section dovetails with the surface exposure location of the fault zone speculated by the shallow seismic prospecting in this area.The concentration anomaly of Rn,H2 and CO2 indicates that there are four faults on the south side and two faults on the north side,which reveals all the faults exhibit a characteristic of high angle.The CO2 concentration anomaly in the south part is consistent with the macroscopic anomaly of the underground liberated gas,which should be considered as non-structural cause.