川北诺水河景区溶洞分布特征及影响因素探析

An analysis on distribution characteristics and influencing factors of karst caves in Nuoshuihe scenic spot in northern Sichuan

选取诺水河景区48个典型溶洞为研究对象,参阅本地区区域地质图和水文地质图,在对洞穴发育高度、层位、构造位置、发育方向、节理走向,以及地下水和地表水系部分特征进行详细调查前提下,利用最邻近距离法、节理分析法、GIS缓冲区法等方法,对溶洞群的洞口高程分布、洞穴发育方向、空间分布格局、洞穴与构造及地表水系关系等分布特征进行了分析,并对溶洞群分布特征的影响因素进行了探析。结果表明,①洞口高程分布在空间上具有层级性,在时间上具有阶段性,研究区洞穴主要沿北西西、北东东向发育,并且越接近地表河流洞穴出口分布越多,洞穴群呈凝聚态分布,越接近构造转折端洞穴分布越密集;②影响洞穴分布的主要因素包括:地层和碳酸盐岩岩性差异,构造派生节理发育状况以及多期次构造变形和构造隆升,地下水的类型和作用,地表水系对地下水系的影响,以及北亚热带季风气候条件下地形的影响等。

Objectives:The systematic analysis on the distribution regularities and influencing factors of cave groups can provide reference for the study on the distribution characteristics of karst cave groups in other regions,and provide a basis for the effective protection and in-depth development of cave groups.Methods:Taking 48 karst caves of cave group in Nuoshuihe scenic spot in northern Sichuan as the research object,based on the regional geological maps and hydrogeological maps,this study carried out a background investigation of the cave developmental horizon,structural position,development direction,joint orientation and some characteristics of groundwater and surface water system.Using the method of nearest distance method,joint analysis method and GIS buffer zone analysis,this study explored the spatial distribution pattern of caves,the developmental direction of caves,the relationship between caves and structures and surface water systems,and analyzed the influencing factors of the distribution characteristics of karst caves.Results:The results show that:karst caves in the study area was in line with aggregation distribution pattern,and the caves develop mainly along the NWW and NEE.In addition,the closer to the surface river,the more cave outlets distributed;the closer to the tectonic turning point,the more intensive distribution of caves is.The cave entrance elevation distribution is hierarchical in space and phased in time.Conclusions:The main factors affecting the distribution of caves include:the lithological differences of strata and carbonate rocks,the derived joints development status of geological,the multiperiodic structure deformation and uplift,the type and effect of groundwater,the influence of surface water system on groundwater system and the influence of topography in north subtropical monsoon climate.