压实作用下黏土弱透水层的有机碳释放量评估  

Evaluation of Release Amount of Organic Carbon from Clayey Aquitard under Compaction

作　　者：刘锐 陈娟 邱文凯 彭子琪 马腾[3] Liu Rui;Chen Juan;Qiu Wenkai;Peng Ziqi;Ma Teng(China Institute of Geo-Environment Monitoring,Beijing 100081,China;Hebei Geological Environment Monitoring Institute,Shijiazhuang 050000,China;School of Environmental Studies,China University of Geosciences,Wuhan 430078,China)

机构地区：[1]中国地质环境监测院,北京100081 [2]河北省地质环境监测院,河北石家庄050000 [3]中国地质大学环境学院,湖北武汉430078

出　　处：《地球科学》2024年第7期2600-2613,共14页Earth Science

基　　金：国家自然科学基金项目(No.41630318)。

摘　　要：为定量评估压实过程中黏土弱透水层对相邻含水层的有机碳释放量,以沉湖湿地研究区钻孔沉积物的背景值为约束条件,采集表层原状淤泥开展了自然沉积和人为压实两种压实模式的物理模拟实验,建立了表征不同深度有机碳释放量差异性的数学模型.自然沉积条件下,有机碳通过矿化和相结合矿物的还原溶解随孔隙水释放;黏土层(厚度约20 m)压实释放的有机碳对下伏含水层(厚度约50~80 m)地下水的浓度贡献为6.99~11.19 mg/L,约是对流和扩散作用的3.9倍.人为压实以地面沉降为例,有机碳的浓度贡献为0.19~2.02 mg/L,高于同一时期的对流和扩散作用.黏土弱透水层的压实释水是地下水中有机碳的重要来源,在天然劣质地下水的研究中应引起重视.In order to quantitatively assess the amount of organic carbon(OC)released by clayey aquitard to adjacent aquifers during compaction,the background values of OC in borehole sediments were used as the constraint condition in the study area of the Chen Lake Wetland.The physical simulation experiments of natural sedimentation and artificial compaction were carried out by collecting surficial undisturbed silt,and a mathematical model representing the difference of release amount of OC at different depths was established.Under natural deposition conditions,sediment OC was released with pore water through mineralization and reduction dissolution of associated minerals;the concentration contribution of OC to the underlying aquifer(about 50-80 m)from clayey aquitard(about 20 m)is 6.99-11.19 mg/L under compaction,which is about 3.9 times of OC release amount under advection and diffusion.Under artificial compaction condition represented by land subsidence,the concentration contribution of organic carbon is 0.19-2.02 mg/L under compaction,which is higher than that of advection and diffusion in the same period.Compaction release of clayey aquitard pore water is an important source of OC in groundwater,which should be paid more attention in the study of natural inferior groundwater.

关 键 词：黏土弱透水层 孔隙水 有机碳 释放量评估 模拟实验 水文地质 

分 类 号：P641.2[天文地球—地质矿产勘探]