@article{oai:nagoya.repo.nii.ac.jp:00011871,
 author = {安原, 正也 and YASUHARA, Masaya and 高橋, 浩 and TAKAHASHI, Hiroshi A. and 稲村, 明彦 and INAMURA, Akihiko and 高橋, 正明 and TAKAHASHI, Masaaki and 風早, 康平 and KAZAHAYA, Kohei and 半田, 宙子 and HANDA, Hiroko and 林, 武司 and HAYASHI, Takeshi and 中村, 俊夫 and NAKAMURA, Toshio and 太田, 友子 and OHTA, Tomoko},
 journal = {名古屋大学加速器質量分析計業績報告書},
 month = {Mar},
 note = {In the Kanto plain, the largest Quaternary groundwater basin in Japan, artesian groundwater samples were obtained from 144 boreholes to characterize the geologic constraints of the faults on regional groundwater system. The spatial variation in chloride (Cl^-) concentration shows that there exists groundwater with Cl^- concentrations of more than 100 mg/l (up to 216 mg/l) between 150 m and 430 m depth below ground surface. This 8 km wide, 35 km long Cl^--rich area, spreading from the northwest to the southeast, corresponds with the so-called Motoarakawa tectonic zone bounded by the faults on its longer sides. We have found the Cl^--rich groundwater is also characterized by the low δD and δ^<180>O values. In this study, twenty-two radiocarbon (^<14>C) and δ^<13>C data indicate that the retention time of groundwater in the Motoarakawa tectonic zone is much longer in comparison with that outside the tectonic zone. Both these chemical and isotopic evidences strongly suggest the Motoarakawa tectonic zone divides the regional groundwater system of the Kanto plain into three distinct hydrologic subareas. Two faults bordering the tectonic zone act as barriers to the southward and northeastward regional movements of groundwater in the Kanto plain. As a result, the Motoarakawa tectonic zone has been put under an isolated hydrologic environment for a long period of time with respect to the active regional groundwater system, resulting in the occurrence of groundwater with anomalous water chemistry and isotopic composition., タンデトロン加速器質量分析計業績報告 Summaries of Researches Using AMS 平成19 (2007)年度},
 pages = {184--189},
 title = {関東平野中央部における被圧地下水の^<14>C濃度分布 : 地質構造との関連性について(タンデトロン加速器質量分析計業績報告平成19(2007)年度)},
 volume = {19},
 year = {2008}
}