The 16th International Conference on Accelerator Mass Spectrometry

Inter-comparison between 81Kr- and 14C-dating of groundwater

AEC-11

21 Oct 2024, 15:50

20m

GOLDEN CASSIA (金桂厅), 2nd Floor

Oral Presentation Applications of Atmospheric and Environmental C-14 Applications in Atmospheric and Environmental C-14

Speaker

Mr Hao Li (University of Science and Technology of China)

Description

81Kr is a cosmogenic isotope with a half-life of 229 ka. Due to its chemical inertness, it has a uniform distribution in the atmosphere and a simple transport behavior in the environment, avoiding some complexities in 14C dating. Therefore, 81Kr is an ideal tracer in the earth sciences.

Limited by the precision of 81Kr analysis, there is a dating gap between 14C and 81Kr. Recently, we have achieved high precision 81Kr-dating method, reaching 1% analytical uncertainty of relative abundance for groundwater samples between 10 ka and 230 ka. This improvement now allows for direct comparison between 14C and 81Kr, enabling multi-tracer approaches in groundwater research.

We have applied our high precision ATTA method to groundwater samples from the North China Plain, and compared it with 14C measurements (AMS). Our results not only verify the reliability of high precision 81Kr-dating method, but also open the opportunity to go beyond piston flow model in groundwater research.