https://repository.kopri.re.kr/handle/201206/9838 Fri, 17 Apr 2026 16:41:14 GMT 2026-04-17T16:41:14Z https://repository.kopri.re.kr/handle/201206/11002 Title: Cyclostratigraphic age constraining for Quaternary sediments in the Makarov Basin of the western Arctic Ocean using manganese variability Authors: Park, Kwangkyu; Kim, Junghyun; Asahi, Hirofumi; Polyak, Leonid; Khim, Boo-Keun; Schreck, Michael; Niessen, Frank; Kong, Gee Soo; Nam, Seung-il Abstract: The Quaternary paleoenvironmental history of the Arctic Ocean remains uncertain, mainly due to the limited chronological constraints, especially beyond the 14C dating limits of accelerator mass spectrometry (AMS). The difficulty in establishing reliable chronostratigraphies is mainly attributed to low sedimentation rates and diagenetic sediment changes, resulting in very poor preservation of microfossils and altered paleomagnetic records. In the absence of independent chronostratigraphic data, the age model of Pleistocene sediments from the Arctic Ocean is mainly based on cyclostratigraphy, which relates lithologic changes to climatic variability on orbital time scales. In this study, we used the Mn/Al record measured from the sediment core ARA03B-41GC retrieved from the Makarov Basin in the western Arctic Ocean. The Mn/Al variation were tuned to the global benthic oxygen isotope stack (LR04) curve under different assumptions for computational correlation. Regardless of assumptions, our computational approach led to similar ages of about 600？1,000 ka for the bottom part of the core. These age models were up to about 200 ka older than those derived from lithostratigraphic approaches. Interestingly, our new age models show that the Ca/Al peak, a proxy for a detrital input from the Laurentide Ice Sheet, first occurred about 150 ka earlier than those previously proposed. Therefore, our results suggest that the glaciers in northern North America developed more extensively at about 810 ka than in earlier glacial periods, and influenced the sedimentary and paleoceanographic environments of the Arctic Ocean much earlier than previously thought. In order to establish a more comprehensive age model, more work is needed to validate our findings with different sediment cores recovered from the western Arctic Ocean. Sat, 01 Feb 2020 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/11002 2020-02-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/11001 Title: Late Quaternary depositional and glacial history of the Arliss Plateau off the East Siberian margin in the western Arctic Ocean Authors: Joe, Young Jin; Polyak, Leonid; Schreck, Michael; Niessen, Frank; Yoon, Seok Hoon; Kong, Gee Soo; Nam, Seung-il Abstract: Sedimentary stratigraphy and facies analysis along with seismostratigraphic and multibeam bathymetry data are used to reconstruct the last glacial impact on the Arliss Plateau (AP) and attendant sedimentation in the adjacent Chukchi Basin (CB) in the western Arctic Ocean off the East Siberian margin. Sediment core ARA02B/16B-GC from the AP lower slope captures glacier-related depositional history during the last estimated ca. 100 ka (Marine Isotope Stage, MIS 1 to 5c) based on regional lithostratigraphic correlation. The sedimentary record shows distinguishable interglacial (interstadial) and glacial (stadial) patterns. The identified sedimentary facies reflect several modes of glaciogenic deposition by drifting icebergs, suspension settling from turbid meltwater plumes and/or detached underflows, and turbidity currents. Based on strong seismic reflectors related to lithological boundaries, a downslope subbottom profile from AP to CB is divided into seismostratigraphic units (SSU) 1 and 2 corresponding in the core record to MIS 1？3 and MIS 3-5c, respectively. An acoustically transparent lens within SSU 2 correlates on the upper slope to debris lobes downslope from the AP top covered by megascale glacial lineations. This geomorphic/sedimentary pattern indicates a glacial erosional impact on the AP and proglacial deposition of eroded sediments on the slope and in the basin. Based on the developed sediment stratigraphy and facies analysis, the last debris lobe horizon was deposited in glacial/deglacial environments during late MIS 4 to early MIS 3. The absence of similar glaciogenic debris lobes within SSU 1 indicates no direct glacial impact on the AP during the Last Glacial Maximum (LGM). These results suggest that the last glacial erosion of the AP occurred during or immediately after MIS 4, possibly related to major glaciation in northern Siberia at ~50？70 ka. Wed, 01 Jan 2020 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/11001 2020-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/12628 Title: Collapses of The Northwestern Sector of The Laurentide Ice Sheet During The Last Glaciation Constrained by Ramped Pyrolysis 14c Sediment Dating in The Western Arctic Ocean Authors: Suzuki, Kenta; Yamamoto, Masanobu; Polyak, Leonid; Nam, Seung-il; Rosenheim, Brad; Omori, Takayuki; Irino, Tomohisa; Yamanaka, Toshiro Abstract: Iceberg discharges from the Late Pleistocene Laurentide ice sheet (LIS) to the North Atlantic, known as the Heinrich events (HE), occurred before the abrupt warmings of the DansgaardOeschger (DO) events. However, not all HE corresponded to DO warmings, which could be related to concurrent ice discharges from the northwestern LIS sector to the Arctic Ocean. These iceberg events can be tracked in the Arctic Ocean sediment records, but their relationship with DO events is unclear due to a lack of adequate age control in these mostly carbonate-free sediments. In this study, we develop new age constraints for LIS iceberg discharges to the western Arctic Ocean during the last glaciation by applying both conventional and ramped pyrolysis (RPO) 14C dating. The latter method was developed by Rosenheim et al. (2008) for age estimation for the most reactive portion of bulk organic matter in carbonate-poor sediments. Several sediment cores recovered from the western Arctic Ocean by expeditions on the icebreaker RV Araon and Healy were used for this study. Calcareous foraminifers, where available, were used for conventional 14C dating. Samples for the RPO 14C dating were pyrolyzed from room temperature to 900 °C, and the CO2 release fractions separated at different temperatures were measured for Δ14C. Cores were also analyzed for ice rafted debris (IRD) content, mineral composition, grain size and organic matter to investigate sediment provenance and depositional processes. Dolomite-rich IRD layers in glacial/deglacial sediments indicative of the Canadian Arctic Archipelago provenance were used to track LIS icebergs discharge events. Foraminiferal tests picked from two of the older dolomite layers were 14C dated to 38 ka and 48 ka corresponding to H4 and H5 events, respectively. A distinct kaolinite-rich IRD layer was also recognized in the late MIS2 sediment. To estimate the age of this foraminiferal-barren layer, we applied RPO 14C dating method. Based on the estimated offsets between the ages of CO2 in pyrolized organic matter and conventional 14C datings, the kaolinite-rich layer corresponds to the deglaciation period, possibly in relation to LIS meltwater drainage event. Wed, 01 Jan 2020 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/12628 2020-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/12394 Title: Participated in IOP drilling with Araon in Lomonosov Authors: Nam, Seung-il; Stein, Ruediger Abstract: 후기 중생대부터 신생대에 이르기까지 북극해 생성 이후 진화를 통해 온실 하우스에서 빙하 하우스 조건으로 변하면서 대륙빙하와 해빙의 생성이 전 지구적인 기후변화에 미친 영향은 전 세계 기후학자들의 주요 관심사로 남아있다. 대부분 북극해 해저퇴적물에 보존된 과거의 기후변화 기록은 피스톤이나 중력 코어 비교적 길이가 짧은 퇴적물 시추를 통해 획득하였기 때문에 그 시기가 수 십 만년 기록에 국한되어 있다. 2004년 국제공동해저시추프로그램(IODP)의 일환으로 다년빙의 두꺼운 해빙으로 덮인 북극점 주변의 로모노소프 해령에서 신생대 기후 역사의 기록을 획득하기 위한 심부시추인 IODP Arctic Core Expedition 302 (ACEX)가 최초로 수행되었다. ACEX 시추를 통해 북극해에서 일어났던 신생대 이후의 기후환경 역사에 대한 중요한 기록을 획득하였지만 대부분의 신생대 중반인 약 2600백만 년 사이의 기록은 결층(Hiatus)로 남아있다. 따라서 ACEX 프로그램에서 획득하지 못한 북극해 기후환경변화의 연속적인 기록을 획득하기 위해 두 번째 시추가 17년 만에 Lomonosov Ridge 남부해령에서 다시 추진 될 예정이다. 이번 시추의 목적은 북극해에서 제 3기층에 대한 연속적이고 완전한 기후 역사의 재구성에 중점을 두고 있으며 2021년 여름에 IODP Expedition 377(ArcOP) 프로그램으로 추진 될 예정이다. 특히 북극해 생성과 진화 과정에서 의문으로 남아있는 과학적 이슈를 해결하기 위해 선정된 최적의 시추 위치는 18,000t 급 독일 쇄빙선 “폴라스턴” 탐사를 통해 시추해역에서 획득한 탐사자료를 통해 결정 되었다. 2021년 북극해 로모노소프 해령 시추 캠페인의 성공적인 미션을 수행하기 위하여 시추에 필요한 시추선 1척과 다년빙 등의 위험 요인을 제거하고 연구실 플랫폼 제공을 위한 2척의 쇄빙선이 필요한 실정이다. 특히 IODP와 ECORD(유럽연합해저시추컨소시엄)에서는 2004년에 이어 두 번째로 북극해에서 추진되는 거대지구과학프로그램에 우리나라 쇄빙선 “아라온”의 참여를 강력하게 희망하고 있다. 극지연구소는 2010년 이후 쇄빙선 “아라온” 탐사를 통해 수행된 극지연구소의 북극해 탐사연구 결과를 통해 4기 빙하기 동안 동시베리아 대륙붕에 거대빙하가 여러 차례 존재하였던 사실을 독일 AWI 연구팀과 공동으로 2013년 국제학술지에 최초로 밝힌바 있다. 또한 2015년 서북극해 척치해 심해분지에서는 아라온에 장착된 JPC 롱코어 시스템을 이용하여 14m 길이의 최장 코어를 획득하여 약 50만 전 이후 일어난 서북극해 빙하역사 기록을 확보하여 현재 연구를 수행하고 있다. 따라서 “아라온”과 함께 북극해에서 얻은 과학적 성과를 기반으로 극지연구소는 2021년 북극해에서 추진되는 IODP 시추프로그램에 쇄빙선 "아라온"의 참여를 추진하고 있다. 이를 통해 북극에서 추진되는 거대지구과학프로그램에 직접 참여함으로써 향후 북극해에서 빅사이언스 연구를 선도적으로 추진 할 수 있는 노하우를 확보할 수 있을 것이다. Tue, 01 Jan 2019 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/12394 2019-01-01T00:00:00Z