https://repository.kopri.re.kr/handle/201206/11923 2026-04-07T05:07:51Z https://repository.kopri.re.kr/handle/201206/13905 Title: Chronostratigraphy of the Larsen blue-ice area in northern Victoria Land, East Antarctica, and its implications for paleoclimate Authors: Lee, Giyoon; Ahn, Jinho; Ju, Hyeontae; Ritterbusch, Florian; Oyabu, Ikumi; Buizert, Christo; Kim, Songyi; Moon, Jangil; Ghosh, Sambit; Kawamura, Kenji; Lu, Zheng-Tian; Hong, Sangbum; Han, Chang Hee; Hur, Soon Do; Jiang, Wei; Yang, Guo-Min Abstract: In blue-ice areas (BIAs), deep ice is directly exposed at the surface, allowing for the cost-effective collection of large-sized old-ice samples. However, chronostratigraphic studies on blue-ice areas are challenging owing to fold and fault structures. Here, we report on a surface transect of ice with an undisturbed horizontal stratigraphy from the Larsen BIA, northern Victoria Land, East Antarctica. Ice layers defined by dust bands and ground-penetrating radar (GPR) surveys indicate a monotonic increase in age along the ice flow direction on the downstream side, while the upstream ice exhibits a potential repetition of ages on scales of tens of meters, which result from a complicated fold structure. Stable water isotopes (δ18Oice and δ2Hice) and components of the occluded air (i.e., CO2, N2O, CH4, δ15N-N2, δ18Oatm (= δ18O-O2), δO2/N2, δAr/N2, 81Kr and 85Kr) are analyzed for surface ice and shallow ice core samples. Correlating δ18Oice, δ18Oatm, and CH4 records from the Larsen BIA with ice from previously drilled ice cores indicates that the gas age at various shallow vertical coring sites ranges between 9.2-23.4 kyr BP, while the ice age sampled from the surface ranges from 5.6 to 24.7 kyr BP. Absolute radiometric 81Kr dating for the two vertical cores confirms ages within acceptable levels of analytical uncertainty. A tentative climate reconstruction suggests a large deglacial warming of 15±5℃ (1σ) and an increase in snow accumulation by a factor of 1.7-4.6 (from 24.3 to 10.6 kyr BP). Our study demonstrates that BIAs in northern Victoria Land may help to obtain high quality records for paleoclimate and atmospheric greenhouse gas compositions through the last deglaciation, although in general climatic interpretation is complicated by the need for upstream flow corrections, evidence for strong surface sublimation during the last glacial period, and potential errors in the estimated gas age-ice age difference. 2022-06-15T00:00:00Z https://repository.kopri.re.kr/handle/201206/13521 Title: Variations in lead isotopes in Antarctic snow from northern Victoria Land during 2012-2015 Authors: Han, Changhee; Kim, Songyi; Lee, Ah-Hyung; Han, Yeongcheol; Lee, Seungmi; Chang, Chaewon; Hong, Sungmin; Jung, HyeJin; Hong, Sang-Bum; Lee, Jeonghoon; Hur, Soon Do Abstract: To evaluate recent changes in anthropogenic Pb pollution and its sources and origins in Antarctica, Pb and Ba concentrations and Pb isotopic compositions were determined in a continuous series of 40 snow samples from a 2-m deep snow pit, covering 4 full years from 2011/12 summer to 2015/16 summer, at the Hercules Neve plateau in Victoria Land, Antarctica. The results show that more than 90% of the atmospheric Pb deposited in Victoria Land was of noncrustal origin. This result implies the persistence of a significant human impact on the atmospheric cycle of Pb in the most remote places on Earth, despite a substantial reduction in anthropogenic Pb emissions in the Southern Hemisphere during recent years. The Pb isotopic fingerprints indicate that South America, particularly Brazil and Chile, has become a major source of anthropogenic Pb reaching Victoria Land. Our data highlight the need for both national and international measures to further reduce Pb emissions. 2022-05-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/13628 Title: Molecular Mechanism of Gas Diffusion in Ice-Ih Authors: Yi, Yoo Soo; Han, Yeongcheol; Kwon, Kideok D.; Lee, Sung Keun; Hur, Soon Do Abstract: Atmospheric gases trapped in polar ice have been used to reconstruct polar and global climate changes, providing better time resolution when less diffused. Experiments have shown that gas diffusion in ice is negligible on a laboratory time scale, but its cumulative impact on old glacial ice (>1M yr remains unclear. Here, we employ density functional theory calculations to investigate the diffusion mechanism of gases trapped in ice-Ih from the atomistic level. The results suggest that the diffusion energy barrier between interstitial sites is primarily dependent on the atomic size and charge distribution of hopping gases. The diffusion of noble gases (He, Ne, Ar, Kr, and Xe) primarily occurs via the interstitial mechanism, consistent with previous results of classical molecular dynamics simulations. In contrast, the precisely determined diffusion paths and energy barriers for CO2, O-2, and N-2 suggest that these molecular gases prefer to hop along the hexagonal channel also via the interstitial mechanism, and the bond-breaking mechanism proposed previously to explain the diffusion of those molecular gases as fast as Ne may be unnecessary. 2021-11-18T00:00:00Z https://repository.kopri.re.kr/handle/201206/13641 Title: Reductive Adsorption of Atmospheric Oxidized Mercury on Ice: Insights from Density Functional Calculations Authors: Yi, Yoo Soo; Han, Yeongcheol; Hur, Soon Do Abstract: The fate of atmospheric mercury (Hg) has been intensively investigated due to concerns about its global dispersion. The reduction of reactive oxidized Hg (Hg-II) to the stable form (Hg-0) is a significant process, in that it extends the mean atmospheric lifetime of Hg and allows for its long-range transport. While the reduction mechanisms of Hg-II in aqueous, particulate, and gas phases have drawn much attention, the reaction pathway and mechanism of Hg-II reduction in icy environments are still elusive, despite that ice particles have been expected to play an active role, from field and laboratory observations. With density functional theory calculations, we reveal the adsorptive and dissociative pathways of Hg-II on ice, including the catalytic role of the ice surface that facilitates the dissociative adsorption of Hg dihalides. Because ice is the most common phase of water in the upper atmosphere and cryosphere, its influence on Hg speciation can have profound implications on the global Hg cycle. 2021-11-18T00:00:00Z