确定平原地下水^4He年龄方法的尝试——以河北平原为例  

A Preliminary Study of ^4He Age of Groundwater： A Case Study of Hebei Plain

作　　者：蔡鹤生[1] 鄢志华[1] 刘存富[1] 周爱国[1] 张俊刚[1] 李延河[2] 宋鹤彬[2] 

机构地区：[1]中国地质大学环境学院,湖北武汉430074 [2]中国地质科学院矿产资源研究所,北京100037

出　　处：《地球学报》2005年第B09期275-278,共4页Acta Geoscientica Sinica

基　　金：本文由中国地质调查局地质调查综合研究项目（编号：200320150002）和国家自然科学基金项目（编号：40372112）资助.

摘　　要：放射性衰变产生的氦组分（^3H衰变产生^3He，U／Th衰变产生^4He）广泛地用于地下水测年。本文分析了地下水中惰性气体的组成，采用过剩空气非分馏（UA）模型进行了单独氦组分的分离。结果表明，河北平原第三含水组（Q2）中的过剩。He是含水组内原地产量和深部地壳通量的共同作用的结果。由于缺乏确定氦平衡参数的约束很好的客观分析，选择应用地下水流模型主观调节来估算迭代过程中的外部通量和流速场，然后根据这个模型所取得的^4He年龄与应用其他方法包括^14C测年和水文模型取得的年龄进行了对比。Being very important, radiogenic components of helium （^3He from ^3H, ^4He from U/Th） have been extensively used for groundwater dating. In this paper, the components of inert gases in groundwater were analyzed, and the separation of the individual helium component was performed with the unfractionated excess air （UA） model. The excess ^4He contained in third aquifer （Q2） discussed in this study came from the in-situ production of U/Th disintegration and the deep crustal flux. With no possibility of a well-constrained objective analysis of the parameters for determining the helium balance, the authors chose to estimate the external flux and the velocity field in an itemtive process by using subjective tuning of a groundwater flow model. The ^4He ages obtained from this model were then contrasted with ages obtained from other methods including ^14C dating and hydrological modeling.

关 键 词：惰性气体 ^4He年龄 地下水 河北平原 地下水流模型 年龄 ^14C测年 放射性衰变 ^3HE 过剩空气 

分 类 号：P641.2[天文地球—地质矿产勘探] P641.8[天文地球—地质学]