• Establishment of Chemical Preparation Methods and Development of an Automated Reduction System for AMS Sample Preparation at KIGAM

      Hong, Wan; Park, Jung Hun; Kim, Kyeong J.; Woo, Hyung Joo; Kim, Jun Kon; Choi, Han Woo; Kim, Gi Dong (Department of Geosciences, The University of Arizona, 2010-01-01)
      Many previous studies on the sample preparation of various kinds of radiocarbon dating samples by accelerator mass spectrometry (AMS) have been examined at KIGAM (Korea Institute of Geoscience and Mineral Resources) and our own procedures have been established. Furthermore, an automated reduction system has been developed. The volume of the reduction region was minimized to improve the reduction yield, and air-actuated pneumatic valves and solenoid arrays were used for computer control of the system. Operation of all the valves and vacuum pumps and signals from the temperature sensors and pressure gauges were interfaced to a personal computer with an A/D board. A computer program was also developed to perform automatic operation of the reduction system. This system consistently shows a higher reduction yield than 90%. The reduction time of the system is currently 140 min.
    • Radiocarbon Dating of the Mansuri Paleolithic Site, Cheongwon, Korea

      Kim, K. J.; Jull, A. J. T.; Kim, Ju Yong; Lee, Yung Jo; Hong, Wan; Park, Jung Hun; Woo, Hyung Joo (Department of Geosciences, The University of Arizona, 2010-01-01)
      Construction of a new science complex in Osong, Cheongwon-gun, Korea, has allowed the investigation of 14 different Paleolithic localities, excavated during 2005-2007. Here, we investigated localities 1 and 12 of the Mansuri Paleolithic site to obtain chronological information using radiocarbon dating. The soil deposition rates varied from 0.09 to 0.15 mm/yr over the period ranging from 33 to 31 kyr BP for locality 1. Locality 12 samples were more recent, 10 ka, and have similar accumulation rates, averaging 0.11 mm/yr. The soil ages of locality 12 were found to be younger than 10 kyr BP. Results for both soil and organic materials at this locality gave much younger ages at shallower depths than the ages expected by the Korean Paleolithic cultural history for this region. Therefore, these more recent deposits may not be associated with the cultural layers and are interpreted to have been hydrologically modified following emplacement. 14C dates of the soil and organic materials at locality 12 confirm that there is evidence for multiple human occupations throughout the last 9 kyr BP.