https://repository.kopri.re.kr/handle/201206/5400 2026-04-22T02:11:13Z 2026-04-22T02:11:13Z Yi, Sang-Bong Lee, Mi Jung Park, Sung Hyun Han, Seung Hee Yang, Yun Seok Choi, Hakkyum https://repository.kopri.re.kr/handle/201206/10871 2022-03-24T07:14:07Z 2019-08-01T00:00:00Z

Title: Occurrence of ice-rafted erratics and the petrology of the KR1 seamount trail from the Australian-Antarctic Ridge Authors: Yi, Sang-Bong; Lee, Mi Jung; Park, Sung Hyun; Han, Seung Hee; Yang, Yun Seok; Choi, Hakkyum Abstract: A multi-disciplinary study of the KR1 segment of the Australian-Antarctic Ridge has been conducted since 2011. We present geochemical and age dating results for samples dredged from three sites on the KR1 seamount trail. The majority of the samples are alkaline ocean island basalts with subdominant enriched tholeiites. The samples from the DG05 bathymetric depression include ice-rafted erratics from Antarctica, which consist of gabbro, diabase, various granitoids, volcanic rocks such as trachyte and rhyolite and deformed or undeformed sedimentary rocks. The main provenance of glacial erratics is considered to be the the Ross Sea region. However, Carboniferous to Cretaceous ages of erratics indicate that some of these may originate from the western regions of West Antarctica. Based on the size and topography of the volcanic features and geochemical characteristics of the alkaline ocean island basalts (La/SmN = 2.62-3.88; Tb/YbN = 1.54-2.67) and the enriched tholeiites, the KR1 seamount trail is interpreted to be a submarine hotspot chain that is the product of alkaline volcanic eruption and seafloor spreading.

2019-08-01T00:00:00Z Park, Sung Hyun Langmuir, Charles H. Sims, Kenneth W. W. Blichert-Toft, Janne Kim, Seung-Sep Scott, Sean R. Lin, Jian Choi, Hakkyum Yang, Yun Seok Michael, Peter J. https://repository.kopri.re.kr/handle/201206/9662 2022-03-24T07:14:04Z 2019-03-01T00:00:00Z

Title: An isotopically distinct Zealandia？Antarctic mantle domain in the Southern Ocean Authors: Park, Sung Hyun; Langmuir, Charles H.; Sims, Kenneth W. W.; Blichert-Toft, Janne; Kim, Seung-Sep; Scott, Sean R.; Lin, Jian; Choi, Hakkyum; Yang, Yun Seok; Michael, Peter J. Abstract: The mantle sources of mid-ocean ridge basalts beneath the Indian and Pacific oceans have distinct isotopic compositions with a long-accepted boundary at the Australian？Antarctic Discordance along the Southeast Indian Ridge. This boundary has been widely used to place constraints on large-scale patterns of mantle flow and composition in the Earth's upper mantle. Sampling between the Indian and Pacific ridges, however, has been lacking, especially along the remote 2,000？km expanse of the Australian？Antarctic Ridge. Here we present Sr, Nd, Hf and Pb isotope data from this region that show the Australian？ Antarctic Ridge has isotopic compositions distinct from both the Pacific and Indian mantle domains. These data define a separate Zealandia？Antarctic domain that appears to have formed in response to the deep mantle upwelling and ensuing volcanism that led to the break-up of Gondwana 90？million years ago, and currently persists at the margins of the Antarctic continent. The relatively shallow depths of the Australian？Antarctic Ridge may be the result of this deep mantle upwelling. Large offset transforms to the east may be the boundary with the Pacific domain.

2019-03-01T00:00:00Z Park, Sung Hyun Lee, Kyeong Yong Hauff, Folkmar Lee, Sang-Mook Kamenov, George D. Michael, Peter J. https://repository.kopri.re.kr/handle/201206/9521 2022-03-24T07:14:14Z 2018-09-01T00:00:00Z

Title: Petrogenesis of basalts along the eastern Woodlark spreading center, equatorial western Pacific Authors: Park, Sung Hyun; Lee, Kyeong Yong; Hauff, Folkmar; Lee, Sang-Mook; Kamenov, George D.; Michael, Peter J. Abstract: Seafloor spreading in the Woodlark Basin is taking place on pre-existing arc crust that was produced by the sub- duction of the Indo-Australian Plate into the Pocklington Trough (now inactive) to the south during the Paleo- gene. The Woodlark Basin has a unique tectonic setting characterized by two surrounding subduction zones. To the east, a spreading ridge is also currently being subducted beneath the Solomon Arc. Moreover, long-term subduction ofthe Pacific Plateoccurredinthisarea,which was halted by thecollision of theOntong？Java Plateau withtheVitiazTrench atca.10 Ma.Any oneofthesesubductionzonescouldhaveinfluencedthemantlebeneath the Woodlark Basin. In this study, basalts from the eastern Woodlark Basin spreading center (EWLB; eastern WoodlarkBasinbasalts) wereanalyzedfor majorand trace element compositions and Sr-Nd-Pb isotopiccompo- sitionsto investigate themelting processes andmantleheterogeneity inthis unusualtectonic setting. Our results show that theEWLB canbeclassifiedintothreetypes basedonmajorand trace elements, and Sr？Nd？Pb isotopic characteristics: normal EWLB (N-EWLB), very depleted EWLB (VD-EWLB), and ultra-depleted EWLB (UD-EWLB). N-EWLB are similar to normal mid-ocean ridge basalts (N-MORB) and comprise most of the EWLB. The EWLB formed from local mantle, which is similar to depleted MORB mantle. VD-EWLB are more de- pleted than N-EWLB and have a weak subduction fingerprint. These rocks are characterized by increasing Nb/La with increasing Sm/La, which is a trend that is not produced by peridotite melting. As such, VD-EWLB may have formed by melting of a source containing residual eclogite that had previously undergone low-degree partial melting during subduction, leaving residual rutile in the source. UD-EWLB are extremely depleted relative to globalMORB,haveelevatedH 2 O/CeandBa/Nb ratios similartoback-arcbasinbasalts (BABB),andlower concen- trations of H 2 O and Ba than N-MORB. We propose that UD-EWLB was derived from sub-arc residual mantle that wasenrichedbyfluidandthenexperiencedmeltdepletion.ThesubductionfingerprintsintheVD-andUD-EWLB are not related to the current ridge subduction or earlier, long-term subduction of the Pacific Plate in the northeast of the basin, as they are geochemically distinct from the Solomon Arc, which was strongly influenced by both these subduction systems. Instead, we suggest that the subduction fingerprint of the VD- and UD-EWLB was produced during Paleogene subduction of the Indo-Australian Plate to the south.

2018-09-01T00:00:00Z Simona Retelletti Brogi Hur, Jin Lee, Yun Kyung Morgane Derrien Kim, Kwanwoo Ha, Sun-Yong https://repository.kopri.re.kr/handle/201206/9501 2022-03-24T07:13:14Z 2018-06-15T00:00:00Z

Title: Optical and molecular characterization of dissolved organic matter (DOM) in the Arctic ice core and the underlying seawater (Cambridge Bay, Canada): Implication for increased autochthonous DOM during ice melting Authors: Simona Retelletti Brogi; Hur, Jin; Lee, Yun Kyung; Morgane Derrien; Kim, Kwanwoo; Ha, Sun-Yong Abstract: Sea ice contains a large amount of dissolved organic matter (DOM), which can be released into the ocean once it melts. In this study, Arctic sea ice DOM was characterized for its optical (fluorescence) properties as well as the molecular sizes and composition via size exclusion chromatography and Fourier transformation ion cyclotron resonancemass spectrometry (FT-ICR MS). Ice cores were collected along with the underlying seawater samples in Cambridge Bay, an Arctic area experiencing seasonal ice formation. The ice core samples revealed a marked enrichment of dissolved organic carbon (DOC) compared to the seawater counterparts (up to 6.2 times greater). The accumulation can be attributed to in situ production by the autotrophic and heterotrophic communities. Fluorescence excitation emission matrices (EEMs) elaborated with parallel factor analysis (PARAFAC) evidenced the prevalence of protein-like substances in the ice cores,which likely results fromin situ production followed by accumulation in the ice. Size exclusion chromatography further revealed the in situ production of all DOM size fractions, with the exception of the humic substance fraction. The majority of DOM in both the ice and seawater consists of lowmolecularweight compounds (b350 Da) probably derived by the microbial degradation/transformation of freshly produced DOM. Molecular characterization also supported the in situ production of DOM and highlighted the marked difference in molecular composition between sea ice and seawater. This study provides new insights into the possible role of sea ice DOM in the Arctic carbon cycle under climate change.

2018-06-15T00:00:00Z