• Journal of the Korean earth science society
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• v.45 no.1
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• pp.85-109
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• 2024

Detrital zircon U-Pb dating was performed to determine the depositional age and provenance of sediments in the Cretaceous Muju Basin in Muju-gun, Jeollabuk-do. Six samples were collected from the Seolcheon Tuff (SCT), Bangyiri Formation (BYR), Gobang Member of the Gilwangri Formation (GWR-G), Seochang Member of the Gilwangri Formation (GWR-S), Bukchang Member of the Gilwangri Formation (GWR-B), and Jeogsangsan Formation (JSS). Based on the dating results, the sedimentary strata of the Muju Basin were deposited for approximately 105.6-90.4 Ma corresponding to the Albian to Turonian. The youngest single zircon ages of about 94.4 Ma and 89.6 Ma were confirmed in the samples from the Bangyiri Formation and the Gobang Member of the Gilwangri Formation, respectively, distributed in the western part of the Muju Basin. The relative and numerical ages previously estimated based on the lithostratigraphic correlation of the Gilwangri conglomerate need to be revisited in further research. The results also suggest that most of the sediments filling the Muju Basin were supplied from a limited area adjacent to the basin.

• 한국석유지질학회:학술대회논문집
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• spring
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• pp.42-47
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• 1998

• The Journal of the Petrological Society of Korea
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• v.5 no.1
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• pp.84-88
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• 1996

Pb isotope composition is analyzed from the rock chips of marbles intercalated between gneisses of Muju area and it shows very large variation ($^{206}Pb/^{204}Pb$=23.74~4142, $^{207}Pb/^{204}Pb$=16.32~18.43, $^{208}Pb/^{204}Pb$=36.42~39.75). The data points form well defined positive relationship on $^{206}Pb/^{204}Pb$ vs $^{207}Pb/^{204}Pb$ plot, which corresponds to $1.99{\pm}0.10$($2{\sigma}$) Ga. This age is very similar to the formation ages of the granitic gneisses from Buncheon and Cheondongri (Tanyang), and suggests that the fairly large volume of Sobaeksan Massif suffered regional metamorphism at this time. It is suggested that the most parts of Korean peninsula including Kyeonggi and Sobaeksan Massifs were very close each other and experienced a regional metamorphism together about 2.0 Ga ago from the fact that galenas from whole Korean Peninsula except Kyeongsang Basin and metamorphic rocks from Kyeonggi Massif also reveal a similar slope corresponding 2.0 Ga on Pb-Pb isotope plot.

• The Journal of the Petrological Society of Korea
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• v.26 no.3
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• pp.201-219
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• 2017

The Jinan Basin which includes Maisan locates in the central part of the northern boundary of the Yeongnam Massif. The basement rocks of the Jinan Basin and surrounding area are Precambrian gneiss and Mesozoic granite which were exposed on the surface before Cretaceous. The Jinan Basin, one of the Cretaceous pull-apart basins in South Korea, formed along the Yongdong-Gwangju fault system. Maisan is composed of conglomerate deposited in the eastern slope of the Jinan Basin showing the shape of horse ears and the unusual topography where many tafonies were developed. The strike slip fault that caused the Jinan Basin was connected to the deep depth so that the magma formed at 200 km depth could have extruded on the surface causing active volcanic activity in and around the Jinan basin. As a result, Cheonbansan composed of pyroclastic rocks, Gubongsan consisting of volcanic neck and WoonilamBanilam formed by the lava flow, appear around Maisan forming a specific terrain. After the formation of the Jinan Basin and surrounding volcanic rocks, they uplifted to form mountains including Masian; the uplifting time may be ca. 69-38 Ma. At this time, the Noryeong mountain range may be formed in the regions which extended from Chugaryeong through Muju and Jinan to Hampyeong dividing the Geumgang and Seomjingang water systems. Due to the ecological barrier, the Noryeong mountain range, Coreoleuciscus splendidus living in the Geumgang water systems was differentiated from that in the Soemjingang water system. In addition, the Geumgang and Mangyeong-Dongjingang water systems were separated by the Unjangsan, which developed in the NNW direction. As a result, diverse ecosystem have been established in and around Maisan and at the same time, diverse cultural and historical resources related to Maisan's unique petrological features, were also established. Therefore, Maisan and surrounding area can be regarded as a place where a geotourism can be successfully established by combining the ecological, cultural and historical resources with a geological heritage. Therefore Maisan and surrounding areas have a high possibility to be a National Geopark and UNESCO Global Geopark.

• Korean Journal of Medicinal Crop Science
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• v.10 no.5
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• pp.415-418
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• 2002

Ligusticum chuanxiong Hort. is one of the most important root-using medicinal crops in Korea. A new variety 'Sinto' (Suwon 2) was developed from the population of Muju local through phenotyptic restricted mass selection at National Crop Experiment Station, RDA. in 2001. The average yield of this variety was about 2,260 kg/ha in RYT at three location from 1999 to 2001 which were about 20% higher than that of Pyeongchang local. Sinto showed a strong resistance to powdery mildew. This variety may be well adaptable to mountainous mid-southern areas in Korean peninsula.

• Economic and Environmental Geology
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• v.48 no.1
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• pp.1-13
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• 2015

The geology of the Seungryung Zn deposit, located in the Muzu basin, consists of Precambrian leucocratic granitic gneiss, Cretaceous clastic rocks, pyroclastic rocks, and intrusive rocks. The deposit shows a weakly skarnized hydrothermal replacement ore developed along limestone bed in the gneiss. The mineralization can be divided into three stages: the early skarnization producing garnet and pyroxene, the main mineralization in the middle stage precipitating most metallic minerals such as magnetite, sphalerite, chalcopyrite, pyrrhotite, Pb-Ag-Bi-S system minerals, and the late stage for altered or low temperature minerals such as chlorite and marcasite. Pb-Ag-Bi-S system minerals include heyrovskite-eskimoite solid solution, lillianite-gustavite solid solution, and vikingite. Chalcopyrite diseases are quite common in sphalerite showing bead chains and dusting textures. The ${\delta}^{34}S$ values of sulfides minerals are concentrated within the narrow range of 3.4~4.1‰ for pyrite, 3.3~4.3‰ for sphalerite, 4.0~4.3‰ for chalcopyrite, and 2.8‰ for galena, suggesting that most sulfur is of igneous origin. Sulfur isotope geothermometry is calculated to be $346{\sim}431^{\circ}C$, implying that the mineralization occurred at relatively high temperature. FeS contents of sphalerite are relatively high in the range of 6.58~20.16 mole% (avg. 16.58 mole%) with the enrichment of Mn compared to Cd, similarly to representative skarn Pb-Zn deposits in South Korea. On the contrary, sphalerite from Au-Ag deposits in the Seolcheon mineralized zone around the Seungryung deposit is enriched in Cd, showing similar feature like representative epithermal Au-Ag deposits. This suggests that around the related igneous rocks, magnetite and sphalerite were produced at high temperature in the Seungryung deposit, and with decreasing temperature and compositional change of mineralizing fluids, Au-Ag mineralization proceeded in the Seolcheon mineralized zone.

• Journal of Korean Society of Forest Science
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• v.44 no.1
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• pp.1-25
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• 1979

Six natural populations of Pinus densiflora S. et Z. as shown in the location map (Flg 1) were studied during 1978. The numerial pouplation codes, 13 to 18. The results of populations 1 to 12 were reported in previous papers. Following the study methods described before, 20 trees were sampled from each population and morpological characteristics such as stem forms, branching habit needle and wood properties investigated. The results are summerized as follows; 1. The mean stand ages were ranged from 36 to 97 of years. The growth performances of trees of population 14. 15 and 18 was similar, but 13, 16, and 17 seemed to be inferior more or less. 2. The ratios of clear bole length were 0.70 in population 18 as the highest but 0.28 for population 16 as the lowest. 3. The population 17 was considered to be a stand of the coarser branching habit having the crown index (The maximum crown diameter/the crown height) 158 though the branching angles were almost horizontal. 4. The differences were observed in the clear bole length ratios and crown-indices between population as shown In Fig. 3 and 4. 5. As to the serration density, number of stomata row and resin duct; the significant differences exist between individual trees within population and also between populations. 6. Population 18 shown resin duct index 0.119 as the maximum. 7. The patterns of diameter growth, based on the width of 10-year-ring segment unit(for example, the 1st segment denotes the with between pith center and 10th year ring and the 2nd one is from 11th to 20th ring and so on.), were alike among populations as shown in Fig 9. 8. Significant differences between population in mean summer wood percentage as well as in wood specific gravity was observed. The values of wood specific gravity were increased with the increase of ages in population 14, 18 however vice versa in population 13, 15, and 17. 9. The fiber length was mereased with the increased of age but no differences between populations as shown in Fig. 12.