@article{oai:nagoya.repo.nii.ac.jp:00011724,
 author = {高橋, 浩 and Takahashi, Hiroshi A. and 風早, 康平 and Kazahaya, Kohei and 稲村, 明彦 and Inamura, Akihiko and 塚本, 斉 and Tsukamoto, Hitoshi and 森川, 徳敏 and Morikawa, Noritoshi and 安原, 正也 and Yasuhara, Masaya and 高橋, 正明 and Takahashi, Masaaki and 中村, 俊夫 and Nakamura, Toshio and 太田, 友子 and Ohta, Tomoko and 丹生, 越子 and Niu, Etsuko},
 journal = {名古屋大学加速器質量分析計業績報告書},
 month = {Mar},
 note = {花崗岩帯における2本のボーリング調査によって得られた地下水試料の炭素同位体組成の変化について,水質データとともに議論した.この2つのボーリング地点は,4〜5km以内の同一岩体にあるにもかかわらず,水質,同位体データは異なる傾向を示した.これは,裂罅の連結性と関わりがあり,裂罅水には表層や地下深くからの流体が混入していることが示された.それらの混入の度合いは,裂罅の連結性が高いサイトで大きなものであった.水そのものと,溶存している炭素成分の混入率は同一のものではなく,得られた ^<14>C濃度から算出する年代値は,裂罅水がトラップされた時期や平均滞留時間を示すものではないが,δD・δ^<18>O の結果とあわせて考えると,裂罅水がトラップされてから非常に長い時間が経過しており,その後に徐々に水が入れ替わっているようなプロセスが示唆された., Chemical nature or origin of groundwater in cracks has been poor understood because of difficulties on collection of water samples preserving its natural conditions. Little is known on the quantification on stability and mean residence time of crack water also. We conducted a study on the flow parameter and/or processes of groundwater in cracks by drilling two bore holes for collection of water samples, and analysis using the the multi-isotopic approach. The drill sites have set in a granitic province called Abukuma in Fukushima prefecture, and drill holes 140m- and 180m-deep were made. In situ sampling of waters at 6 depths for each drill holes are done with the single or double packer method. Chemical type of groundwater has changed at depth 40m, the shallower groundwater is categorized as Ca-HCO_3^- type with slight NO_3 contamination whereas deeper groundwater has Na-HCO_3^- type. Bicarbonate concentration becomes greater in deeper level suggesting that older groundwater is placed in deeper cracks. Stable isotope composition of water showed that all the sample water is meteoric origin. However, the δD at deeper level has significantly low values (20‰ lower than the present one). Obviously those groundwater do not originate from the present one. The δ^<13>C values of total dissolved carbon from two sites, Shirasawa and Miharu, show different profiles vertically. The δ^<13>C profiles indicate that carbon at the Shirasawa site is derived from biogenic source, but that at the Miharu site is influenced from other sources, such as "crustal fluid" upwelling from a deep geologic environment. The contribution of crustal fluid can be canceled using the carbon isotopic mass balance, and the δ^<14>C value of crack water excluding deep source contribution was evaluated. The apparent ^<14>C date calculated using the evaluated δ^<14>C value is getting older to deeper depth at both sites. At the Miharu site, the tritium is detected even at depth of 180m, indicating that relatively young water has mixed in the crack water. As the vertical profiles of δD and δ^<18>O show the very small change, implying the vertical mixing of crack water, shallow surface water and deep crustal fluid. However, the result beyond the 10000 yrBP in the apparent ^<14>C date suggests that the carbon mixing does not frequently occurred. As for the Shirasawa site, vertical profiles of δD and δ^<18>O show large changes. The deeper the crack water, the lower theδD and δ^<18>O values are represented. Groundwater with very low δD and δ^<18>O values is likely recharged in an ice age. The apparent ^<14>C date also show that the older age of carbon in the crack water than 10000 or 20000 yrBP. The evidence shows that crack water can be trapped for a very long period even at shallow depth (80-180m)., 第16回名古屋大学タンデトロン加速器質量分析計シンポジウム(平成15年(2003年度)報告 Proceedings of the 16th Symposium on Researches Using the Tandetron AMS System at Nagoya University in 2003 日時:平成16(2004)年1月22日(木)､23日(金) 会場:名古屋大学シンポジオン Date:January 22nd and 23rd,2004 Place:Nagoya University Symposion Hall},
 pages = {66--73},
 title = {ボーリング調査により採取された地下水の ^<14>C濃度 : 花崗岩地域における調査例(第16回名古屋大学タンデトロン加速器質量分析計シンポジウム平成15(2003)年度報告)},
 volume = {15},
 year = {2004}
}