https://repository.kopri.re.kr/handle/201206/15843 2026-04-19T16:19:37Z https://repository.kopri.re.kr/handle/201206/16057 Title: Glaciovolcanic processes between the Campbell Glacier and Mt. Melbourne Volcano, Antarctica: ICE and FIRE Authors: Rhee, Hyun Hee; Lee, Min Kyung; Seong, Yeong Bae; Kim, Sunghan; Lee, Jae Il; Yoo, Kyu-Cheul; Yu, Byung Yong Abstract: This study investigates the glacial dynamics of the Campbell Glacier in Terra Nova Bay (TNB), Antarctica, with a focus on its unique lowering patterns during the late Quaternary. Using cosmogenic nuclides (10Be) surface exposure dating, we provide significant chronological constraints on Antarctic terrestrial glacier changes. In addition to the previous data on Marine Isotope Stage (MIS) 5 simple exposure ages of Campbell Glacier moraines, we further analyzed the palaeo-subglaciated bedrock, which yields exposure ages during MIS 3 and 2 (49.8-28.5 ka). Our analysis empowers that continuous glacial lowering occurred throughout the late Quaternary, even during the Last Glacial Period (MIS 4-2), and that the Local Last Glacial Maximum (LLGM) occurred at 150-90 masl during MIS 4 rather than MIS 2. This new and recalculated dataset for the Campbell Glacier is unique compared to other outlet glaciers flowing into the Terra Nova Bay, highlighting the significant influence of Mt. Melbourne's volcanic activity via glaciovolcanic processes during the late Quaternary, beyond general climatic and oceanic factors. Further studies of palaeo-glaciovolcanic interactions on the East Antarctic Ice Sheet (EAIS) promise to provide more robust insights for refining models predicting future accelerated glacial melt and sea level rise, particularly considering the numerous volcanoes beneath the West Antarctic Ice Sheet (WAIS). 2025-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/16056 Title: A Holocene Paleosecular Variation Record From the Northwestern Ross Sea, Antarctica Authors: Truax, Olivia J.; Nelson, Faye; Riesselman, Christina R.; Ohneiser, Christian; Lee, Jae Il; Yoo, Kyu-Cheul; Dagg, Bob; Wilson, Gary Abstract: We present a mid-to-late Holocene record of relative paleosecular variation from the Ross Sea region of Antarctica. The 6,700-year-long record of inclination, declination, and relative paleointensity from a marine sediment core collected near Cape Adare is independently dated using a combination of ramped pyrolysis oxidation and carbonate radiocarbon dates. Agreement between the large-scale features of the relative paleointensity record and the virtual axial geomagnetic dipole moment suggests that changes in the record are dominated by the dipole component of the Earth's geomagnetic field. Correspondence between the record and a non-independently dated reconstruction from the Antarctic Peninsula indicates regionally coherent changes in the geomagnetic field intensity in the southern high latitudes during the mid-to-late Holocene. The prominent features of the record serve as stratigraphic markers for hard-to-date Antarctic sedimentary records and a constraint on Holocene geomagnetic field behavior when incorporated into the next generation of geomagnetic field models. 2025-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/16342 Title: Anisotropy of magnetic susceptibility of sediments in the Ross Sea continental rise, antarctica: Evaluation of paleocurrent variability reconstruction Authors: Shin, Ji Young; Lee, Min Kyung; Kang, Myung-Il; Joo, Young Ji Abstract: The Antarctic continental margins exhibit unique sedimentary characteristics influenced by climatic changes in glacial environments and oceanic circulation. This study aims to trace the variability of bottom current and associated paleoenvironmental conditions in the Ross Sea continental rise through comprehensive interpretation of sedimentary facies, grain size distribution, and anisotropy of magnetic susceptibility (AMS). The sedimentary facies of the studied core are divided into two, diamictite with abundant ice-rafted debris (IRD) and laminated silt lacking IRD. Silty sediments with well-developed wavy contact and cross laminae indicate the influence of sustained bottom currents. The diamictite layers display faint or absent sedimentary structures and abundant bioturbation, but occasionally contain graveland sand-rich layers formed by bottom-current winnowing. AMS results show that the degree of magnetic anisotropy (P') has no consistent relationship with sedimentary facies and grain size variations, probably due to disturbances from secondary magnetic fabrics, and is not regarded as a direct proxy for current intensity. However, enhanced oblate fabrics align with the laminated silts and gravel-rich layers, contourite deposition by geostrophic currents flowing around the Ross Sea. These results imply that magnetic fabrics may sensitively reflect sedimentary processes that vary with bottom current systems in the Ross Sea (e.g., lamination and winnowing), highlighting the need for future magnetic studies in various polar environmental settings.; 남극 대륙주변부 퇴적물은 기후에 따른 빙하 환경 및 해양 순환 변화의 영향을 받아 고유의 퇴적 특성을 기록한다. 본 연구에서는 로스해 대륙대에서 해류 변동성과 관련된 고환경 복원을 위하여 퇴적상, 입도분포 및 대자율 이방성(Anisotropy of magnetic susceptibility, AMS) 분석을 수행하였다. 퇴적상은 빙운쇄설물이 풍부한 다이아믹트와 조립질 입자가 거의 없는 엽층리 실트로 구분된다. 엽층리 실트 퇴적상에는 파형의 경계부 및 사엽층리가 잘 발달되어 있으며, 이는 지속적인 저층 해류의 영향을 지시한다. 다이아믹트 퇴적상은 생물 교란 구조가 빈번하고 퇴적구조가 뚜렷하지 않지만, 저층 해류의 키질작용에 의한 박층의 역질/사질층이 종종 관찰된다. AMS 분석 결과, 이방성 정도(P')는 퇴적상 및 입도 변화와 연관성을 보이지 않으며, 이는 교란 등에 의한 자성입자의 2차적인 배열의 결과로 판단된다. 따라서 P'의 변동성은 본 연구에서 해류 세기의 직접적인 지시자로 적용하기 어렵다. 그러나 이방성 타원체는 엽층리 실트 및 역질/사질층이 협재된 다이아믹트 구간에서 강화된 편원구조(oblate) 특성을 보이며, 이는 로스해 주변의 지형류에 의한 등수심 퇴적체 형성 모델과 일치한다. 이러한 결과는 자성입자의 배열을 반영하는 자기 이방성 조직이로스해 저층 해류 순환에 따라 엽층리 형성 및 키질 작용과 같은 퇴적 기작의 변화를 민감하게 반영할 수 있음을 시사하며, 향후 다양한 극지 환경에서의 AMS 연구 및 퇴적 지시자를 이용한 종합적 해석의 필요성을 강조한다. 2024-09-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/16375 Title: ADVANCING ANTARCTIC SEDIMENT CHRONOLOGY THROUGH COMBINED RAMPED PYROLYSIS OXIDATION AND PYROLYSIS-GC-MS Authors: Ginnane Catherine E.; Turnbull Jocelyn C.; Naeher Sebastian; Rosenheim Brad E.; Venturelli Ryan A.; Phillips Andy M.; Reeve Simon; Parry-Thompson Jeremy; Zondervan Albert; Levy Richard H.; Yoo, Kyu-Cheul; Dunbar Gavin; Calkin Theo; Escutia Carlota; Pastor Julia Gutierrez Abstract: Radiocarbon (14C) dating of sediment deposition around Antarctica is often challenging due to heterogeneity in sources and ages of organic carbon in the sediment. Chemical and thermochemical techniques have been used to separate organic carbon when microfossils are not present. These techniques generally improve on bulk sediment dates, but they necessitate assumptions about the age spectra of specific molecules or compound classes and about the chemical heterogeneity of thermochemical separations. To address this, the Rafter Radiocarbon Laboratory has established parallel ramped pyrolysis oxidation (RPO) and ramped pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) systems to thermochemically separate distinct carbon fractions, diagnose the chemical composition of each fraction, and target suitable RPO fractions for radiocarbon dating. Three case studies of sediment taken from locations around Antarctica are presented to demonstrate the implementation of combined RPO-AMS and Py-GC-MS to provide more robust age determination in detrital sediment stratigraphy. These three depositional environments are good examples of analytical and interpretive challenges related to oceanographic conditions, carbon sources, and other factors. Using parallel RPO-AMS and Py-GC-MS analyses, we reduce the number of radiocarbon measurements required, minimize run times, provide context for unexpected 14C ages, and better support interpretations of radiocarbon measurements in the context of environmental reconstruction. 2024-01-01T00:00:00Z