九寨沟火花海堤坝修复后的水化学与钙华沉积研究  

Water chemistry and tufa deposition on the restored dam of Huohua Lake in the Jiuzhai Valley

作　　者：刘秦 晏浩 肖维阳 肖瑶 周率 谢瑶 乔雪 唐亚[1,5] LIU Qin;YAN Hao;XIAO Weiyang;XIAO Yao;ZHOU Lyu;XIE Yao;QIAO Xue;TANG Ya(College of Architecture and Environment,Sichuan University,Chengdu,Sichuan 610065,China;International Center for Isotope Effects Research,School of Earth Sciences and Engineering,Nanjing University,Nanjing,Jiangsu 210023,China;Jiuzhaigou National Nature Reserve Administration,Aba Tibetan and Qiang Autonomous Prefecture,Sichuan 623402,China;Institute of New Energy and Low-Carbon Technology,Sichuan University,Chengdu,Sichuan 610065,China;State Key Laboratory of Hydraulics and Mountain River Engineering,Sichuan University,Chengdu,Sichuan 610065,China)

机构地区：[1]四川大学建筑与环境学院,四川成都610065 [2]南京大学地球科学与工程学院国际同位素效应研究中心,江苏南京210023 [3]九寨沟国家级自然保护区管理局,四川阿坝藏族羌族自治州623402 [4]四川大学新能源与低碳技术研究院,四川成都610065 [5]四川大学水力学与山区河流开发保护国家重点实验室,四川成都610065

出　　处：《中国岩溶》2023年第3期495-508,共14页Carsologica Sinica

基　　金：四川省灾后重建遗产保护恢复专项(5132202019000128,5132202020000046);四川省科技厅国际科技合作项目(2020YFH0023)。

摘　　要：钙华的主要成分是以方解石为主的碳酸钙(CaCO_(3))。2017年九寨沟7.0级地震导致火花海下游钙华堤坝溃堤,火花海干涸。火花海上下游的钙华堤坝和内部的钙华丘暴露在空气中,因物理与化学风化作用,钙华堤坝持续坍塌;虽然在有水的情况下,钙华也可能受到侵蚀,但因地表水会不断析出新的钙华,使钙华景观不断地进行“自我修复”。火花海钙华堤坝决口修复后,对其开展相关监测,结果表明:(1)地表水的方解石饱和指数大于0,表明地表水倾向于析出CaCO3,利于涵养现有钙华堤坝;(2)堤坝表面上有新的钙华沉积:基于碳氧同位素、矿物和元素分析,新沉积的钙华可能主要来自地表水;(3)新沉积钙华的成分受流域水土流失的一定影响;(4)与天然堤坝上原有的钙华相比,修复堤坝上新沉积的钙华在物理结构、痕量元素组成和有机质含量上具有一定差异,且细菌多样性相对较低,这主要是由于修复堤坝上植被以自然恢复为主,植被和钙华中微生物的自然恢复是一个缓慢的过程。相关水化学和钙华监测应持续开展,以更好掌握钙华堤坝的未来演变趋势。In 2017,an Ms 7.0 earthquake breached the tufa dam of Huohua Lake in the Jiuzhai Valley,resulting in the lake drainage.Exposed to the atmosphere,the tufa dam collapsed due to continued physical and chemical weathering.To prevent further collapse,the dam of Huohua Lake was restored by using the modified glutinous rice mortar and local limestone rocks.After the restoration,we monitored the chemical and isotopic compositions of surface water and tufa to answer the following questions.Does the surface water after the earthquake tend to conserve the tufa dam and precipitate tufa?Does the modified glutinous rice mortar have a significant impact on the surface water in the lower part of Huohua Lake?Does new tufa deposit on the restored dam?What are the characteristics and main sources of newly-deposited tufa?Are there any differences between the old tufa on the natural tufa dam and the newly-formed tufa on the restored dam?The characteristics of surface water and tufa samples were investigated.First,from September 2020 to September 2021,the surface water of Huohua Lake was monitored once a month.The parameters included pH,conductivity,temperature,alkalinity,turbidity,DO,K^(+),Ca^(2+),Na^(+),Mg^(2+),SO_(4)^(2-),NO_(3)^(-),NH_(4)^(+),dissolved organic carbon(DOC),and calcite saturation index(SIC).We also compared these parameters between the values before and after the earthquake.Second,to examine the physical and chemical characteristics of tufa,we used the scanning electron microscope(SEM)and X-Ray Diffractomer(XRD)for tufa samples and analyzed the elemental compositions(Ca,Mg,Al,Si,P,S,K,Fe and Ba),organic matter,and carbon and oxygen isotopes in the modified glutinous rice mortar,tufa samples,and surface water.Third,the characteristics of microorganisms in the tufa samples were quantified by using the highthroughput sequencing technology.The SIc values of surface water after Huohua Lake restoration were 0.77±0.11,indicating that the surface water tended to precipitate CaCO_(3)^(-).From the upstream to downstream of H

关 键 词：钙华景观 矿物组成 微生物 有机质 碳氧同位素 

分 类 号：P512.2[天文地球—地质学] P641.134