An in situ cosmogenic 14C extraction system at the Atmosphere and Ocean Research Institute, The University of Tokyo

Abstract

In situ14C surface exposure dating is a powerful tool for understanding the Earth’s surface processes during the late Quaternary. This study developed an in situ14C extraction system that heats samples to 1650 °C to extract in situ14C from quartz. The initial experiments showed a high blank level (1.80 × 107 14C atoms) and low extraction efficiency (5.36%). Each procedural step required a blank test to understand the cause of the high background, and the results identified several components of the extraction system as sources of 14C contamination. After improving the apparatus design, the new system showed a sufficiently low blank level (5.32 × 104 14C atoms). The extraction efficiency ranged from 111% to 127% with this system. These results show that the system is capable of extracting in situ14C from quartz for surface exposure dating.