龙门山冲断带盆山体系地下水循环特征分析——以石亭江流域绵竹段为例

Characteristics of groundwater circulation in basin-mountain system of Longmenshan alluvial belt:case of Mianzhu section of Shiting River Basin

山区与平原区水资源联系密切,探究山区-盆地地下水循环可为水资源开发和合理利用提供科学依据。龙门山冲断带及川西前陆盆地是中国典型的盆山系统代表,结合现场采样及前人研究结果,采用水文地质调查、水化学特征、氢氧同位素和聚类分析等技术方法,阐明了绵竹市境内石亭江流域龙门山冲断推覆体与前陆盆地形成的盆山体系的地下水循环特征。研究认为:大气降水为山区及平原区浅层地下水的主要补给来源,其中J_3l~3地层还接受石亭江水的侧向补给;地形对山区浅层地下水径流具有主控作用,主要沿北西、南东方向发生径流,对近平原区的浅层地下水给予少量补给;平原区浅层还接受地表水、河渠水补给,地下水自北西向南东发生运移,在玉泉镇至板桥镇附近以泉的形式进行排泄。NW向断裂构造沟通盆山体系,来源于研究区北西侧更高山区的地下水沿断裂带形成深部径流带,形成具有较高矿化度的热水。研究成果可为类似山区-盆地地下水循环系统研究提供参考。

The water resources of mountainous and plain areas are closely connected,and the investigation on the mountain-basin groundwater cycle can provide a scientific basis for the development and rational utilization of water resources.The Longmenshan alluvial belt and the western Sichuan foreland basin are typical representatives of the basin-mountain system in China.Combined with the field sampling and the results of previous studies,the groundwater circulation characteristics of the basin-mountain system formed by the Longmenshan alluvial overburden and the foreland basin in the Shiting River Basin in the territory of Mianzhu section were clarified by using hydrogeological investigation,hydrochemical characterization,hydrogen and oxygen isotopes,and cluster analysis methods.The study concludes that atmospheric precipitation is the main recharge source of shallow groundwater in the mountainous areas and plains,in which the J 3 l 3 stratum also receives lateral recharge from the Shiting River.Topography has a dominant role in controlling the shallow groundwater runoff in the mountainous areas,which mainly occurs along the north-west and south-east directions,and has a small amount of recharge of the shallow groundwater in the near-plain areas.The shallow layer in the plains also receives recharge from surface water and river and canal water,and the groundwater moves from northwest to southeast,finally it discharges in the form of springs along Yuquan Town to Banqiao Town.As the NW fracture structure connects with the basin-mountain system,the groundwater from the higher mountainous areas in the NW side of the study area forms a deep runoff zone along the fracture zone,forming hot water with high mineralization.The study results can be used as a reference for similar studies of mountain-basin groundwater circulation systems.