河南省汤阴地堑南部土壤H2浓度及其与构造关系

采用网格化布点野外流动观测的方法测量了汤阴地堑南部380个点的土壤 H₂ 浓度,分析其空间分布特征及其与构造的关系,并进一步揭示出气体地球化学特征与区域地质构造背景间的联系. 研究结果表明,汤阴地堑南部土壤 H₂ 浓度介于(0．26~175．50)×10^-6,背景均值为(17．25±11．19)×10^-6,异常阈值下限为57．30×10^-6.在空间上,土壤 H₂ 呈现出西低东高的分布特征,受覆盖层厚度和地表沉积特征的影响,低于背景值的测点主要分布于研究区西部.高值异常测点主要集中在研究区东部并沿汤中、汤东断裂带分布,H₂ 浓度等值线高值中心点连线与断裂带走向基本一致,汤西断裂带虽没出现高值异常,但 H₂ 浓度相对高值仍然在断裂带及邻近区域,反映出构造对 H₂ 释放的控制作用.同时,土壤 H₂ 等值线空间分布也显示,在研究区存在一条北东-南西向的 H₂ 浓度高值异常条带,推测存在一条规模较大的隐伏断裂.研究区主要断裂带 H₂ 浓度表现为汤西断裂带显著低于汤中、汤东断裂带,而异常衬度表现为汤西断裂带、汤中断裂带小于汤东断裂带.结合研究区地球物理探测资料分析认为 H₂ 浓度及异常衬度是构造活动背景的反映,部分深部来源的 H₂ 通过深大断裂及有利的深浅构造组合向地表扩散迁移,在地壳浅部与浅源 H₂ 混合,并在断裂带上覆土壤层形成浓度高值异常条带.需进一步开展 H₂ 在汤阴地堑南部构造活动监测中的应用探索.同时也需要对研究区由北东-南西向 H₂ 浓度异常条带而推测出的隐伏断裂开展进一步深入研究.

Hydrogen concentration in soil gas along the southern Tangyin graben,Henan Province, and associated relation with tectonic activities

This paper focuses on the hydrogen concentration in the soil gas of 380 measuring points in the southern Tangyin graben and reveals the relationship between the spatial distribution characteristics of hydrogen concentration and tectonic activities in this area. The results show that the hydrogen concentration in soil gas in the southern Tangyin graben ranges from 0.26×10^-6to 175.50×10^-6. The background mean value and lower threshold are (17.25±11.19)×10^-6and 57.30×10^-6, respectively. The hydrogen concentration in soil gas shows the spatial distribution characteristics, i.e., low in the west and high in the east. The points with a hydrogen concentration below the background value are mainly scattered in the western part of the study area, which resulted from the overburden thickness and surface sedimentary characteristics, whereas the high-value abnormal points are mainly concentrated in the east part of the study area and distributed along the Tangzhong and Tangdong fault zones. The line connecting the high-value points of the hydrogen concentration isoline is basically consistent with the fault strike. Although there is no high-value anomaly in the Tangxi fault zone, the relatively high hydrogen concentration value is still along the fault zone and its adjacent areas, reflecting the control of the fault structure on the hydrogen release. Furthermore, the spatial distribution of the hydrogen concentration isoline shows a high-value abnormal band with the NE-SW trending in the study area. Thus, we speculated that there is a large-scale hidden fault. The hydrogen concentration in the Tangxi fault zone is significantly lower than that in the Tangzhong and Tangdong fault zones. Based on the geophysical exploration data in the study area, the hydrogen concentration and abnormal contrast are considered the reflection of the tectonic activity background. Some deep-source hydrogen diffuses and migrates to the surface through the deep fault and favorable deep-shallow tectonic association. It mixes with the shallow-source hydrogen in the shallow part of the crust and forms a high concentration abnormal band in the fault zone. Therefore, the application of hydrogen in the monitoring of tectonic activities in the south of Tangyin graben should be further explored.