https://repository.kopri.re.kr/handle/201206/11560 2026-04-26T03:37:17Z 2026-04-26T03:37:17Z Hong, Jongsun Woo, Jusun Park, Tae-Yoon S. Kim, Ji-Hoon Kim, Young-Hwan G. Lee, Hee-Kwon https://repository.kopri.re.kr/handle/201206/13550 2022-07-07T00:34:31Z 2021-09-01T00:00:00Z

Title: Middle Cambrian slope deposits in northern Victoria Land, Antarctica: Fingerprinting small carbonate platforms dominated by grainy carbonates and microbial reefs Authors: Hong, Jongsun; Woo, Jusun; Park, Tae-Yoon S.; Kim, Ji-Hoon; Kim, Young-Hwan G.; Lee, Hee-Kwon Abstract: Carbonate-bearing slope strata are reported from the upper Miaolingian-lower Furongian Spurs Formation in northern Victoria Land, Antarctica, deposited in a backarc basin during the Ross Orogeny. The Spurs Formation consists mainly of shale interbedded with conglomerate and sandstone. It overlies the middle Miaolingian Glasgow Volcanics and volcaniclastic Molar Formation and is overlain by the lower Furongian sandstone-dominated Eureka Formation. The Spurs conglomerate is composed of randomly-oriented, granule- to boulder-sized, polymictic clasts of shale, sandstone and various limestone. These limestone clasts are variable in texture, such as microbial boundstone composed of calcimicrobe Epiphyton and subordinate microbial crust, oolitic-peloidal packstone to grainstone, and minor lime mudstone to wackestone. These are collectively interpreted as slope deposits, in which limestone clasts may have been derived from missing platform margin carbonate, analogous to Cambrian to Lower Ordovician slope successions elsewhere. On the other hand, the rarity of thinly bedded micritic limestones in the Spurs slope successions is markedly distinctive, and possibly reflects subdued production of lime muds behind the platform edge. It suggests that the vanished carbonate platform may have formed within a narrow shelf margin, dominated by coarse-grained carbonate and microbial reefs. Such style of carbonate platforms would contribute to understand how syn-orogenic carbonates initiated and developed in back-arc basins along the pacific margin of Gondwana (i.e., southern Australia and New Zealand).

2021-09-01T00:00:00Z Yi, Sang-Bong Lee, Mi Jung Park, Sung Hyun Nagao, Keisuke Han, Seunghee Yang, Yun Seok Choi, Hakkyum Baek, Jongmin Sumino, Hirochika https://repository.kopri.re.kr/handle/201206/12984 2022-03-24T07:15:13Z 2021-06-03T00:00:00Z

Title: Alkalic to tholeiitic magmatism near a mid-ocean ridge: petrogenesis of the KR1 Seamount Trail adjacent to the Australian-Antarctic Ridge Authors: Yi, Sang-Bong; Lee, Mi Jung; Park, Sung Hyun; Nagao, Keisuke; Han, Seunghee; Yang, Yun Seok; Choi, Hakkyum; Baek, Jongmin; Sumino, Hirochika Abstract: Coexisting alkalic and tholeiitic basalt lavas has been identified in a seamount chain located near the Australian-Antarctic spreading ridge. The KR1 Seamount Trail (KR1 ST) is a series of volcanic seamounts extending to the southeast in the spreading direction of the Australian-Antarctic Ridge (AAR). We herein report Sr, Nd and Pb isotopic compositions and (U-Th)/He and K-Ar geochronology for dredge samples from the KR1 ST in order to evaluate mantle processes and the role of enriched components for alkalic to tholeiitic magma generation in this region. The KR1 ST is a medium-sized seamount chain that extends for ~60 km, has a maximum height of ~1600 m above the seafloor, and consists of alkaline basalts and tholeiites with formation ages of ~0.4 Ma to ≤1.3 Ma. The isotopic characteristics of the alkaline basalts (206Pb/204Pb = 19.52-19.91; 87Sr/86Sr = 0.7030-0.7033; 143Nd/144Nd = 0.5128-0.5130) from the KR1 ST reflect a dominant ‘PREMA (or FOZO)’ mantle component represented by radiogenic Pb and mildly enriched Sr and Nd isotopic compositions. On the other hand, the weak PREMA (FOZO)-affinity (206Pb/204Pb = 18.89-18.93; 87Sr/86Sr = 0.7028-0.7029; 143Nd/144Nd = ~0.5130; 3He/4He = 7.64 ± 0.13 (R/RA)) coupled with their enriched mid-ocean ridge basalt (E-MORB) characteristics of tholeiites from the KR1 ST largely overlap with the KR1 MORB composition. The potential source materials for the alkaline basalts are considered to be ancient, recycled oceanic crust (i.e. eclogite) as well as sub-KR1 depleted MORB mantle (DMM). Whereas the main source materials for the KR1 ST tholeiites are presumed to be the DMM-dominant lithology with minor recycled material. We interpret the KR1 ST as a submarine hotspot chain that was formed by asthenospheric upwelling and spreading processes that delivered fertile blobs of recycled oceanic crust to the sub-KR1 region. The fundamental reason for sub-KR1 upper mantle enrichment might be attributed to a mantle plume event that possibly occurred prior to the formation of the KR1 ST.

2021-06-03T00:00:00Z Bomfleur, Benjamin Mors, Thomas Unverfaerth, Jan Liu, Feng Laeufer, Andreas Castillo, Paula Oh, Changhwan Park, Tae-Yoon S. Woo, Jusun Crispini, Laura https://repository.kopri.re.kr/handle/201206/13562 2022-07-07T01:07:26Z 2021-01-01T00:00:00Z

Title: Uncharted Permian to Jurassic continental deposits in the far north of Victoria Land, East Antarctica Authors: Bomfleur, Benjamin; Mors, Thomas; Unverfaerth, Jan; Liu, Feng; Laeufer, Andreas; Castillo, Paula; Oh, Changhwan; Park, Tae-Yoon S.; Woo, Jusun; Crispini, Laura Abstract: The remote lower reaches of the Rennick Glacier in the far north of Victoria Land hold some of the least-explored outcrop areas of the Transantarctic basin system. Following recent international field-work efforts in the Helliwell Hills, we here provide a comprehensive emendation to the regional stratigraphy. Results of geological and palaeontological reconnaissance and of petrographic, geochemical and palynostratigraphic analyses reveal a stack of three previously unknown sedimentary units in the study area: the Lower Triassic Van der Hoeven Formation (new unit, 115+ m thick) consists mainly of quartzose sandstone and non-carbonaceous mudstone rich in continental trace fossils. The Middle to Upper Triassic Helliwell Formation (new unit, 235 m thick) consists of coal-bearing overbank deposits and volcaniclastic sandstone and yielded typical plant fossils of the Gondwanan Dicroidium flora together with plant-bearing silicified peat. The succession is capped by c. 14 m of the sandstone-dominated Section Peak Formation (uppermost Triassic-Lower Jurassic). Our results enable more detailed correlation of the Palaeozoic-Mesozoic successions throughout East Antarctica and into Tasmania. Of particular interest is one section that spans the end-Permian mass extinction interval, which promises to allow detailed reconstructions of high-latitude vegetation dynamics across this critical interval in Earth history. Supplementary material: A Supplementary Data File containing supplementary information, figures S1-S7, and additional references is available at https://doi.org/10.6084/m9.figshare.c.5118431

2021-01-01T00:00:00Z Park, Sun Young Park, Changkun Kim, Hyun Na Lee, Seoyoung Lee, Sung Keun https://repository.kopri.re.kr/handle/201206/11962 2022-03-24T07:15:14Z 2020-12-01T00:00:00Z

Title: Structure of type A CAI-like melts: A view from multi-nuclear NMR study of melilite (Ca2Al2SiO7-Ca2MgSi2O7) glasses Authors: Park, Sun Young; Park, Changkun; Kim, Hyun Na; Lee, Seoyoung; Lee, Sung Keun Abstract: Exploring the polymerization and structural disorder of Ca-Al-rich inclusion (CAI)-like melts is a key question in cosmochemistry due to strong implications for macroscopic properties of melts (i.e., viscosity and diffusivity). Here, we report experimental results showing the effect of composition on the structure of melilite glasses and melts [akermanite (Ak, Ca2MgSi2O7) - gehlenite (Gh, Ca2Al2SiO7)] in type A CAIs with varying composition using high-resolution solid-state nuclear magnetic resonance (NMR). The 27Al magic angle spinning (MAS) and 3Q (triple quantum) MAS NMR spectra of melilite glasses show predominant [4]Al. A non-negligible fraction of [5]Al is observed in Ak50Gh50 and Ak72Gh28 glasses and it slightly increases with increasing akermanite content. The 17O 3QMAS NMR spectra of melilite glasses show that bridging oxygens (BOs, Si-O-Si, Al-O-Al, and Si-O-Al) and non-bridging oxygens (NBOs, Ca-O-Si, Ca-O-Al, and mixed {Ca, Mg}-NBO) are partially resolved. Despite the strong preference of Si over Al for NBOs, for the first time, Ca-O-Al is observed in natural melts (i.e., gehlenite and Ak25Gh75 glasses and melts). The results show that Al-NBO (~150 ppm in MAS dimension) can be distinguished from Si-NBO (~110 ppm) in melilite glasses and melts. The fraction of NBO increases with increasing akermanite content. The experimental results suggest that compositioninduced structural changes should be considered to interpret the melt viscosity, diffusivity, and oxygen isotopic composition of CAI-like melts in the early Solar System.

2020-12-01T00:00:00Z