西南岩溶小流域水体中微量元素地球化学特征及其指示意义  

Geochemical characteristics of trace elements and their implications in the small karst basin,Southwest China

作　　者：吴庆 黄芬[1,2] 郭永丽 肖琼 孙平安[1,2] 杨慧 白冰[1,2] WU Qing;HUANG Fen;GUO Yongli;XIAO Qiong;SUN Ping’an;YANG Hui;BAI Bing(Institute of Karst Geology,Chinese Academy of Geological Sciences/Key Laboratory of Karst Dynamics,MNR and GZAR/International Research Centre on Karst under the Auspices of UNESCO/National Center for International Research on Karst Dynamic System and Global Change,Guilin 541004,China;Pingguo Guangxi,Karst Ecosystem,National Observation and Research Station,Pingguo 531406,China)

机构地区：[1]中国地质科学院岩溶地质研究所/自然资源部、广西岩溶动力学重点实验室/联合国教科文组织国际岩溶研究中心/岩溶动力系统与全球变化国际联合研究中心,广西桂林541004 [2]广西平果喀斯特生态系统国家野外科学观测研究站,广西平果531406

出　　处：《地学前缘》2024年第5期397-408,共12页Earth Science Frontiers

基　　金：国家重点研发计划项目(2021YFE0107100);广西自然科学基金项目(2023GXNSFAA026473,2021GXNSFBA075013,桂科AB22035010,2021GXNSFBA220065,2022GXNSFAA035604);中国地质科学院基本科研业务费项目(2023019,2021001);中国地质调查局地质调查项目(DD20230547);桂林市科学研究与技术开发计划项目(2020010905);自然资源部自然资源科技战略研究项目(2023-ZL-23)。

摘　　要：微量元素在岩溶区资源环境研究中具有重要的指示意义。本文选择我国典型峰丛洼地区岩溶地下河为例,解译水体中微量元素的地球化学特征及其在岩溶空间结构和岩溶水文等方面的指示意义。毛村地下河流域水体中Sr、Cr、Ni、Co和Mn等微量元素,主要来源于碳酸盐岩的溶解。强降水条件可驱动深层水,弱降水条件驱动能力差。微量元素ρ(Ni)/ρ(Co)、ρ(Sr)/ρ(Ca^(2+))和ρ(Sr)/ρ(Mg^(2+))的时空变化,指示LLS和BY子系统内岩溶发育差,SGY至MC岩溶发育程度较高。ρ(Sr)/ρ(Ca^(2+))和ρ(Sr)随ρ(SiO_(2))的变化斜率值可作为指示岩溶发育程度的指标,均随着岩溶作用强度的增大而增大。ρ(Sr)的时空变化特征与地层岩性特征密切相关,可将岩溶流域按照地质背景分为非岩溶区、非岩溶区岩溶区过渡带和岩溶区。基于非岩溶区至岩溶区ρ(Sr)的变化特征,利用质量守恒定律,计算出旱季SGY、SWQ、LLS和BY泉水接收岩溶区补给的平均比例分别为51.50%、50.46%、65.48%和22.16%。微量元素可指示岩溶发育程度和定量计算岩溶水源比例,为解决岩溶区复杂的资源环境问题提供科学指导。Trace elements play a significant role in resources and environmental research in karst areas.In this paper,we examine the geochemical characteristics of trace elements in a typical karst underground river located in a peak cluster depression and discuss their implications for karst spatial structure and hydrology.In the Maocun underground river basin,trace elements such as Sr,Cr,Ni,Co,and Mn primarily originate from the dissolution of carbonates.Intense precipitation can drive deep karst water flow,whereas weak precipitation has limited driving force.Spatial and temporal variations in the ratios ofρ(Ni)/ρ(Co),ρ(Sr)/ρ(Ca^(2+))andρ(Sr)/ρ(Mg^(2+))indicate that the LLS and BY subsystems exhibit limited karst development,while greater karstification is observed from SGY to MC.The ratios ofρ(Sr)/ρ(Ca^(2+))and the slopes ofρ(Sr)relative toρ(SiO_(2))increase with the degree of karst development,making them potential indicators of karstification.The spatial and temporal variations ofρ(Sr)are closely related to the lithologic characteristics of the strata,allowing the division of the basin into non-karst areas,transition zones from non-karst to karst areas,and karst areas based on geological background.Using the changes inρ(Sr)from non-karst to karst areas and applying the principle of mass conservation,we calculated the average proportions of karst water contributions to the SGY,SWQ,LLS,and BY springs during the dry season to be 51.50%,50.46%,65.48%,and 22.16%,respectively.Trace elements can indicate the degree of karstification and quantitatively estimate the proportions of karst water sources,providing scientific guidance for addressing complex resource and environmental issues in karst areas.

关 键 词：微量元素 岩溶地下河 岩溶发育 岩溶水文 

分 类 号：P641[天文地球—地质矿产勘探] P592[天文地球—地质学] P595