https://repository.kopri.re.kr/handle/201206/5272 2026-04-07T05:40:33Z https://repository.kopri.re.kr/handle/201206/6568 Title: Oxygen Isotopic Ratios for Ultramafic Xenoliths from the Korean Peninsula Authors: Lee, Jeong-A; Choo, Mi Kyung; Lee, Jong Ik; Kim, Kyu Han Abstract: This study examined the geochemical characteristics, equilibrium temperature and pressure conditions, and oxygen isotopic ratios of mantle xenoliths from the various geological sites of the Korean peninsula. The results are as follows: (1) The ultramafic xenoliths from the Korean peninsula mainly consist of typical high magnesium olivine (MgO : 49.12-50.95 wt.%, Mg value: 90.1-92.2), corresponding to worldwide Cenozoic ultramafic xenoliths in chemical compositions. (2) The pressure-temperature conditions of ultramafic xenoliths in the Korean peninsula are from 854 to 1016℃ and 4.6 to 24.4 kbar. (3) The oxygen isotopic ratios (δ18O) for olivines in ultramafic xenoliths range from 5.06 to 5.51, which are relatively uniform oxygen isotopic values and overlapped by the values of N-MORB and upper mantle peridotite (δ18O: 5.2±0.2). However, olivines of the ultramafic xenoliths from the Baegdusan and Chejudo have a relatively wide δ18O values ranging from 5.07 to 5.51 and 5.07 to 5.45, respectively. Based on the results, this study suggests that the high δ18O signature of the Baegdusan xenoliths give a hint that ~5% of the oxygen in typical EM2 sources originally derived from recycled sediments. 2013-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/6651 Title: Mesozoic carbonatite complexes in Greenland Authors: Park, Byong-Kwon; Lee, Mi Jung; Lee, Jong Ik Abstract: We report the results of the petrographic observations for the representative samples obtained during the field trip at the southwestern part of Greenland. The Tikiusaaq carbonatite complex contains REE carbonate minerals in calcite carbonatites. The representative REE carbonate minerals are strontianite (SrCO3) and ancylite (SrCe(CO3)2(OH)H2O). Strontianite contains Ce and ancylite contains considerable amounts of La, Ce, Nd, respectively. Several Ba-bearing minerals occur in the Qaqarssuk carbonatite complex instead REE carbonates. The complex contains about 4 million tons pyrochlore ores (0.5 wt% Nb2O3). Ba-carbonate (Barytocalcite, CaBa(CO3)2) occurs as a major carbonate mineral and coexists with barite and Ba-Sr carbonatite. In contrast, apatite and REE carbonates occur as minor constituent minerals. 2013-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/8097 Title: 외계 생명체의 흔적을 찾아서 Authors: Lee, Yoo Kyung 2013-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/6197 Title: The A-type Pirrit Hills Granite, West Antarctica: an example of magmatism associated with the Mesozoic break-up of the Gondwana supercontinent Authors: Lee, Hyo Min; Choi, Seok Won; Kim, Jeongmin; Lee, Mi Jung; Lee, Jong Ik Abstract: The Pirrit Hills granite occurs as an isolated pluton in the Ellsworth-Whitmore Mountains block, which is the center of five blocks in the present configuration. The granite consists of quartz, perthitic alkali feldspar, and plagioclase with minor amounts of interstitial biotite and muscovite. The granite is a highly homogeneous, strongly fractionated, and mildly peraluminous granite and belongs to A-type granites with A2-type characteristics, suggesting its generation in an anorogenic environment. The strong enrichment of HREE and significant negative Eu anomalies suggest that the granitic magma was produced by a small degree of partial melting of a garnet granulitic source in the unusually hot lower crust. A weighted mean 206Pb/238U age of zircons is 164.5±2.3 Ma (MSWD=1.3), which is 8 to 9 Mys younger than a former Rb-Sr whole rock age (173±3 Ma), and corresponds to the first rifting stage of the break-up of Gondwana (at 165 Ma). We suggest this age to be the emplacement age of the Pirrit Hills granite. The A-type Pirrit Hills granite was emplaced in the Middle Jurassic accompanying crustal thinning due to the break-up of Gondwana. with minor amounts of interstitial biotite and muscovite. The granite is a highly homogeneous, strongly fractionated, and mildly peraluminous granite and belongs to A-type granites with A2-type characteristics, suggesting its generation in an anorogenic environment. The strong enrichment of HREE and significant negative Eu anomalies suggest that the granitic magma was produced by a small degree of partial melting of a garnet granulitic source in the unusually hot lower crust. A weighted mean 206Pb/238U age of zircons is 164.5±2.3 Ma (MSWD=1.3), which is 8 to 9 Mys younger than a former Rb-Sr whole rock age (173±3 Ma), and corresponds to the first rifting stage of the break-up of Gondwana (at 165 Ma). We suggest this age to be the emplacement age of the Pirrit Hills granite. The A-type Pirrit 2012-01-01T00:00:00Z