ESTIMATION OF THE OCCURRENCE TIME OF THE Δ14C PEAK IN AD 775 BASED ON THE OXIDATION TIME OF 14C IN THE ATMOSPHERE AND Δ14C VALUES IN SUBANNUAL TREE RINGS. Issue 5 (3rd October 2020)

• Record Type: Journal Article
• Authors: Park, Junghun; Seo, Jeong-Wook; Hong, W; Park, G; Sung, Kilho; Park, Yong Jin; Kim, Yo-Jung
• Is Part Of: Radiocarbon. Volume 62:Issue 5(2020)
• Page Start: 1285
• Page End: 1298
• Publication Date: 2020-10-03
• Subjects: M12, -- AD 775, -- occurrence time of M12, -- oxidation time of CO2; Radiocarbon dating -- Periodicals; 930.1028505
• DOI: 10.1017/RDC.2020.69
• Languages: English
• ISSNs: 0033-8222

Abstract

ABSTRACT: The 14 C peak in AD 775 (M12) has been measured and confirmed globally in several studies since it was first measured in annual tree rings by Miyake et al. (2012). However, M12 data measurements in early- and latewood are limited. This paper presents the Δ 14 C values in early- and latewood from AD 762–776 Zelkova serrata tree rings from Bangu-dong, Ulsan, South Korea (35°33′N, 129°20′E). The results indicate no early rise in Δ 14 C values in the latewood of AD 774 in this sample located at mid-latitude. A comparison of the results of this and previous studies suggests latitude dependence (Büntgen et al. 2018 ); that is, the early rise of Δ 14 C in AD 774 was not observed at mid-latitudes in South Korea but was observed at high latitudes in Finland. The half-oxidation time of 14 C was estimated from a detailed analysis of a small bomb peak in AD 1962. Based on the half-oxidation time, the Δ 14 C rise in the latewood, but not in the earlywood, of AD 774 in Finland, and the absence of a Δ 14 C rise in both the early- and latewood of AD 774 in South Korea, the 14 C spike was estimated to have been produced from late April to mid-June in AD 774.