14C Level at Mt Chiak and Mt Kyeryong in Korea

Abstract

We have observed Delta-14C concentrations in the northern hemisphere temperate region in the bomb pulse period, using cross-dated tree ring samples. The tree-ring samples were taken from one 70-year-old and two 50-year-old red pines (Pinus densiflora) on Mt Chiak, Korea and from a 50-year-old red pine (Pinus densiflora) on Mt Kyeryong, Korea. Twenty-two tree-ring samples from four red pines ranging from 1950 to 2000 AD were pretreated to obtain holo-cellulose, combusted to CO2 by an element analyzer (EA) and converted to graphite for Delta-14C measurement using the accelerator mass spectrometry (AMS) facility at Seoul National University. Our results for Delta-14C showed good agreement with those measured by other researchers at similar latitudes. The observed steady decrease of Delta-14C from 1965 to 2000 AD is described by a single exponential function with a lifetime tau = 15.99 +/0.43 yr. This lifetime is similar to that of the high-latitude region in Europe.