https://repository.kopri.re.kr/handle/201206/1 Thu, 05 Mar 2026 08:56:40 GMT 2026-03-05T08:56:40Z https://repository.kopri.re.kr/handle/201206/16471 Title: Grain-size and geochemical evidence for sediment transport mechanisms in the northeastern part of the East Siberian Sea and on the adjacent continental slope Authors: Ovsepyan Ekaterina; Dorokhova Evgeniia; Ovsepyan Yaroslav; Aliev Ramiz; Jin, Young Keun Abstract: Grain-size analyses, end-member modeling, X-ray fluorescence, and radionuclide activity measurements were conducted on sediment minicores collected from the middle-outer shelf of the East Siberian Sea (ESS) and the upper part of the adjacent continental slope to elucidate the sedimentation mechanisms in this poorly studied region. The grain-size data demonstrate that clayey silt and silt strongly dominate on the ESS shelf and the continental slope. In contrast, sandy silt has a patchy distribution. End-member modeling, applied here for the first time, indicates that sea ice (frazil and anchor ice) rafting, and nepheloid transport are the primary processes responsible for distributing sedimentary material across the ESS. The XRF data confirm the results of previous studies, reporting a predominantly lithogenic origin for ESS deposits. Combined grain size and geochemical records suggests that the shelf break area serves as a depocenter for fine silt particles, likely supplied by nepheloid flow, and represents the most productive area in the northeastern ESS. High sea surface productivity likely results from influence of nutrient-rich Pacific-derived waters, the upwelling of transformed Atlanticderived waters, or a combination of both. The accumulation of the high amount of fine silt near the shelf break is suggested to be related to relatively calm bottom-water conditions, resulting from the potential interaction of the northward-flowing cross-shelf currents and episodic southward-moving compensatory flows. Wind direction is considered a key factor controlling the intensity of fine-grained material distribution by nepheloid flows and anchor ice across the ESS shelf. Sedimentation rates derived from the radionuclide activity measurements vary from 1.3 mm yr(-1) on the outer shelf to 1.0 mm yr(-1) on the upper continental slope. Mon, 01 Dec 2025 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/16471 2025-12-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/16469 Title: Wind-Induced Topographic Rossby Waves in the Southwestern Slope of the Chukchi Abyssal Plain Authors: Ku Ahyoung; Donohue Kathleen A.; Watts D. Randolph; Kim Kiduk; Song Hajin; Jeon Chanhyung; Park, Taewook; Cho, Kyoung-Ho; Peacock Thomas; Park Jae-Hun Abstract: Near-bottom currents collected over 1 year (August 2021-22) using a current- and pressure-recording inverted echo sounder (CPIES) at a depth of 1060 m showed fluctuations within a frequency band between 2 and 6.5 days near the southwestern slope of the Chukchi Abyssal Plain. The amplitude of the fluctuations was approximately 8 cm s21 on average during the summer months and weakened to approximately 3 cm s21 between February and June 2022. Similar fluctuations were reproduced by the data-assimilated Hybrid Coordinate Ocean Model (HYCOM), confirming that they were bottom intensified. Calculations of the bottom-trapping scale using HYCOM revealed that these fluctuations could be attributed to topographic Rossby waves (TRWs) with a length scale of approximately 50 km. The spatial distributions of TRWs in HYCOM and ray-tracing results suggest that TRWs likely propagated from the west-southwest. It is suggested that these TRWs were triggered by nonlocal wind stress curl (WSC), 220 km to the west along the continental slope, as the coherence in the TRW frequency band between the TRWs and WSC was significant. The weaker TRW signal from February to June 2022 was related to weaker WSC and higher sea ice concentration in the study area. The stronger TRWs from July to October occurred when the WSC was stronger and the sea ice concentration was lower in the study area. Our findings imply that changes in the Arctic WSC field or a longer sea ice-free season could trigger more energetic and frequent TRWs, observable down to 1000-m depth around the southwestern slope of the Chukchi Abyssal Plain. Mon, 01 Dec 2025 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/16469 2025-12-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/16461 Title: Synchronous mid-Holocene marine and terrestrial deglaciation in the Ross Sea, Antarctica Authors: Parker Rebecca L.; Riesselman Christina R.; Truax Olivia J.; Jones Richard S.; Lee, Jae Il; Lee, Min Kyung; Jacobsen Geraldine; Rosenheim Brad E.; Subt Cristina; Zawadzki Atun; Ginnane Catherine; Naeher Sebastian; Dunbar Gavin; McKay Robert M.; Levy Richard; Turnbull Jocelyn; Yoo, Kyu-Cheul Abstract: The Ross Ice Shelf buttresses ice draining from both East and West Antarctica and its collapse could accelerate the loss of inland ice sheets, rapidly raising sea level. Documenting the location, timing and rate of past glacial retreat can help reveal processes driving rapid mass loss, informing projections of ice sheet responses to a warming climate. Here, we present a record of mid-Holocene ice retreat from the southwestern Ross Sea using facies succession and paired ramped pyrolysis oxidation C-14/Pb-210 chronology. This record shows rapid ice shelf retreat from 6.9-5.4 cal kyr BP, coeval with thinning of adjacent outlet glaciers. Our findings reconcile earlier discrepancies in terrestrial and marine reconstructions, and indicate that synchronous grounding line retreat from west of Ross Island to the Siple Coast at similar to 7-6.2 cal kyr BP was likely driven by warm-water incursions, a process active in parts of Antarctica today. Mon, 01 Dec 2025 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/16461 2025-12-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/16482 Title: Unlocking Martian geology with Martian meteorites Authors: Park, Changkun Abstract: 화성 운석은 현재 지구에서 확보할 수 있는 유일한 화성 암석으로, 화성의 지질 진화를 해석하는 데 핵심적인 단서를 제공한다. 지금까지 보고된 화성 운석은 셔고타이트(shergottite), 나클라이트(nakhlite), 샤시그나이트(chassignite), 사방휘석암(orthopyroxenite), 다성분 표토 각력암(polymict regolith breccia)으로 구분되며, 형성 시기와 암석학적 특징이 다양해 초기 지각부터 최근의화산 활동에 이르기까지 폭넓은 지질 시대를 포괄한다. 이들 운석의 충격 용융 유리에 포획된 가스 성분, 삼중 산소 동위원소 조성비, 감람석과 휘석의 Mn/Fe 비 등이 화성 기원의 주된 증거로 사용된다. 화성 운석에 대한 단반감기 동위원소 및 미량원소 분석을통해, 화성은 태양계 초기에 빠르게 집적되고 분화되었으며, 여러 맨틀 저장소(mantle reservoir)가 장기간 유지되면서 화산 활동이수십억 년 지속되었음이 밝혀졌다. 수성 변질 광물과 수소 동위원소비는 과거 화성에 액체 상태의 물이 존재했으며, 시간이 지나면서 물이 점차 소실되었음을 보여준다. 일부 운석에서 물？암석 반응으로 생성된 유기물과 수화 광물이 보고되었으나, 현재로서는비생물적 기원의 산물로 해석된다. 우주선 노출연대와 충돌 방출 모델링은 방출 기작과 기원 충돌구를 규명하는 데 활용되며, 화성표면 지질과 운석 자료를 이어 주는 중요한 연결 고리 역할을 한다. 현재 추진 중인 화성 시료 회수 임무는 운석 기록이 지닌 불완전한 지질학적 정보와 대표성의 한계를 보완함으로써, 운석 연구 성과와 결합하여 화성의 지질 진화 과정을 보다 정밀하게 재구성하는 데 기여할 것으로 기대된다. Mon, 01 Dec 2025 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/16482 2025-12-01T00:00:00Z