https://repository.kopri.re.kr/handle/201206/15915 2026-04-07T05:03:14Z 2026-04-07T05:03:14Z Park, Kwangkyu Khim, Boo-Keun Choi, Hyuk Shin, Kyung-Hun https://repository.kopri.re.kr/handle/201206/16593 2026-02-10T04:07:10Z 2025-05-01T00:00:00Z

Title: Organic carbon stocks of the surficial sediments in the territorial waters of Korea Authors: Park, Kwangkyu; Khim, Boo-Keun; Choi, Hyuk; Shin, Kyung-Hun Abstract: Shallow marine environments, including the continental shelf, are important in the global carbon cycle in which organic carbon is transported from land, produced within the ocean, and buried in sediments. The territorial waters of Korea (Republic of Korea) encompass predominantly shallow continental shelves. This study examined the organic carbon distribution of surficial sediments in the territorial waters of Korea to approximate the carbon stocks in the surficial sediments of the seafloor at a national scale. For the estimation, the reported data (mean grain size (MGS), total organic carbon (TOC) content, and dry bulk density) around the Korean Peninsula were documented and organized to evaluate the potential for carbon sequestration in the territorial waters of Korea. The distribution of the MGS and the TOC content in surficial sediments varied regionally according to the depositional processes, but they exhibited the typical characteristics of marine sediments whose TOC content increased as the MGS decreased. Among the four zones (A, B, C, and D) in the territorial waters of Korea, the estimated total carbon stock was highest (2.27×10^6 Mg C) in zone A and lowest (1.04×10^6 Mg C) in zone C, despite zone C having the highest carbon stock per unit area (1.64 Mg C/ha). However, for a precise assessment of long-term carbon stock and sequestration rates, more comprehensive and robust data along with representative sedimentation rates and the vertical profiles of the TOC content are essential at a national scale.

2025-05-01T00:00:00Z Park, Kwangkyu Nam, Seung-il Vogt Christoph Frederichs Thomas Kim, Jung-Hyun Khim Boo-Keun https://repository.kopri.re.kr/handle/201206/16427 2025-11-06T08:23:14Z 2024-01-01T00:00:00Z

Title: Cryospheric and Oceanographic Evolution in the Arctic Makarov Basin Since the Early Pleistocene Revealed by Bulk Mineral Assemblages Authors: Park, Kwangkyu; Nam, Seung-il; Vogt Christoph; Frederichs Thomas; Kim, Jung-Hyun; Khim Boo-Keun Abstract: We present the glacial history of the Makarov Basin (western Arctic Ocean) during the last similar to 1.1 Myr, with sediment provenances using the newly refined chronostratigraphy of core ARA03B-41GC02. According to the principal component analysis of the bulk mineral assemblages, felsic minerals were dominant, and their ratios (K-feldspar/plagioclase and quartz/feldspars) indicated that sediment supply to the Makarov Basin was mainly from the Siberian margin and partly from northern North America, including the Canadian Arctic. However, their occurrence did not vary significantly between interglacials and glacials due to the mixed sources. In contrast, clinopyroxene and dolomite indicated specific sediment origins from the eastern Siberian margin and northern North America, respectively. The clinopyroxene content followed an eccentricity cycle (similar to 100-Kyr) during the early to middle Pleistocene, suggesting that the eustatic sea level changes may have influenced its input from the eastern Siberian margin. The dolomite, transported primarily by icebergs from the Arctic sector of the Laurentide Ice Sheet (LIS) in northern North America, has also followed the same cycle since the early Pleistocene. Thus, the mineralogical signals highlight that sediment origins and transport processes in the Makarov Basin were related to ice sheet evolution at the eccentricity cycle. In addition, dolomite deposition in the Makarov Basin began by the early Pleistocene (similar to 790 ka), similar to 150 ka earlier than in previous North Atlantic records (similar to 640 ka), indicating the earlier LIS calving in the Arctic sector than in the Atlantic sector. We investigated past mineralogic changes in the Makarov Basin (western Arctic Ocean) over the last 1.1 million years using marine sediment core ARA03B-41GC02. Bulk mineral analysis revealed that sediments in the Makarov Basin mainly originated from the Siberian margin, with a partial contribution from northern North America. However, sediments deposited during interglacial and glacial periods were mixed from different sources. Nevertheless, specific minerals such as clinopyroxene and dolomite allow us to distinguish different sediment sources between the eastern Siberian margin and northern North America. The clinopyroxene content fluctuated on a cycle of similar to 100-Kyr during the early to middle Pleistocene, suggesting an association with global sea level changes. The variation in dolomite content followed the same cycle, indicating that sediments containing dolomite were mainly transported by icebergs from the Laurentide Ice Sheet (LIS) in northern North America. These results linked sediment sources and transport processes to glacier evolution over cycles of similar to 100-Kyr. Interestingly, our study shows that dolomite deposition in the Makarov Basin began about 790,000 years ago, which is about 150,000 years earlier than previously reported (similar to 640 ka) in the North Atlantic, suggesting an earlier LIS calving into in the Arctic sector than in the North Atlantic sector. Sediment provenances of clinopyroxene and dolomite are different (eastern Siberian margin and North America) in the Makarov Basin Variations in dolomite and clinopyroxene during the Pleistocene follow a similar to 100 Kyr cycle of eccentricity Dolomite in Makarov Basin similar to 150 Kyr earlier than N. Atlantic implies Laurentide Ice Sheet calved into Arctic before extending to N. Atlantic

2024-01-01T00:00:00Z