四川九寨沟诺日朗瀑布钙华大坝放射性及沉积环境意义  

Radioactivity of Nuorilang waterfall travertine dam in Jiuzhaigou valley,Sichuan Province and its implication for the sedimentary environment

作　　者：张红敏 赵学钦[1,2] 王富东[1,2] 吴昌达 李松 ZHANG Hongmin;ZHAO Xueqin;WANG Fudong;WU Changda;LI Song(School of Environment and Resource,Southwest University of Science and Technology,Mianyang,Sichuan 621010,China;Institute of Land and Resources Utilization,Southwest University of Science and Technology,Mianyang,Sichuan 621010,China)

机构地区：[1]西南科技大学环境与资源学院,四川绵阳621010 [2]西南科技大学国土资源利用研究所,四川绵阳621010

出　　处：《中国岩溶》2021年第1期157-165,共9页Carsologica Sinica

基　　金：国家自然科学基金项目(41672206、41973053);地震动力学国家重点实验室开放基金(LED2016B07)。

摘　　要：以九寨沟诺日朗瀑布钙华大坝为研究对象,采用便携式手持伽马仪对大坝坝体进行放射性强度测量,同时对钙华大坝取样,进行主量、微量元素分析,以研究大坝形成的沉积环境。结果表明:大坝表层伽马辐射量平均值为27.57 Ur(当量铀),变异系数为18.73%;钙华主微量元素分析显示钙华颜色与本身所含的色素元素和矿物有关;大坝钙华(La/Yb)N介于8.57~14.93,均值为11.78,具有轻稀土元素富集特征。综合分析认为诺日朗瀑布大坝钙华颜色的形成是多因素共同作用的结果,钙华放射性元素含量与钙华颜色以及伽马值之间存在正相关性,伽马值在钙华沉积环境方面具有指示作用,伽马值越高代表其形成环境相对更湿润。Travertine is a good carrier for the study of paleo-climate and paleo-environment.A portable hand-held gamma meter was used to measure the radioactivity in the Nuorilang waterfall travertine dam in Jiuzhaigou valley.Combined with the analysis of the major and trace elements in the travertine samples,the environment of the dam was studied.Results show that the gamma radiation on the surface of the dam averages 27.57 Ur and the variation coefficient is 18.73%.The travertine color is associated with color elements contained and minerals.(La/Yb)N of dam travertine is between 8.57-14.93,11.78 on average,with a feature of light rare element enrichment.Analysis suggests that the color of dam travertine resulted from multiple factors,including the content of trace elements,climate change,precipitation,and the types and growth of aquatic plants.There is a positive correlation between the content of radioactive elements,travertine color and gamma values.Thus the gamma value can be used to infer the deposition environment of travertine,i.e.the higher the gamma value,the moister the environment is.

关 键 词：九寨沟 诺日朗瀑布 自然伽马 微量元素 沉积环境 

分 类 号：P532[天文地球—古生物学与地层学] P642.25[天文地球—地质学]