Abstract

Knowledge of the groundwater age is indispensable for understanding groundwater flow in crystalline rocks. The present study is the first to discuss the radiocarbon ages of groundwater in Abukuma granite, Fukushima Prefecture, northeast Japan. The vertical profiles of 14C dates and δ13C are obtained from 3 boreholes (depths of 140, 230, and 306 m). Chemical and carbon isotopic compositions suggest that dead-carbon contamination of groundwater occurred during groundwater storage in the fractures. 14C concentration was corrected by using isotopic mass balance in which dead-carbon contamination of the groundwater was considered. The 14C dates ranged from modern to ≃16 ka. The relationship between tritium and 14C data in 1 borehole suggests the simultaneous inflow of shallow groundwater to deeper levels occur for the depths between 60 and 100 m. The vertical profiles of 14C dates indicate a relatively constant age of 10–16 ka for groundwater deeper than 100 m, which may have been influenced by rapid sea-level changes after the glacial period.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.