• The Journal of the Petrological Society of Korea
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• v.14 no.3 s.41
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• pp.149-156
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• 2005

Ar-Ar, carbon AMS and OSL dating was carried out to clarify the age of the human footmarks on the Hamori Formation, Jeju Island, Korea. $^{40}Ar/^{39}Ar$ ages of trachybasalt from the Songaksan Tuff, which is underlain by the Hamori Formation, range between $10.6{\pm}19.9\;Ka$ and $11.7{\pm}26.3\;Ka$. Radiocarbon AMS ages of humin fractions extracted from sediment samples yielded the maximum limit age of the Hamori Formation as $15,161{\pm}70\;yr$ B.P. The OSL dating of the top and bottom layers of the Hamori Formation gave $6.8{\pm}0.3\;ka$ and $7.6{\pm}0.5\;ka$, respectively, suggesting that timing of the human footmarks formation can be constrained as between ca 6,800 yr B.P. and 7,600 yr B.P.

• Economic and Environmental Geology
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• v.24 no.4
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• pp.399-408
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• 1991

There are several tuff cones and tuff rings, now only apparent on the western shoreline in Cheju Island. The observation of their landform, bedform, particle size and sorting reveals that these deposits are mainly emplaced by base surges and/or slurries originating from Surtseyan eruption which is attributed to explosive hydrovolcanism influenced by interaction of magma with external water. These are subdivided into two groups based on the plateau basalt. It is recognized that the distal limb of early tuff cones and ring at Dangsanbong, Dansan, Sanbangsan and Hwasun (lower group) are overlain by plateau basalt, on which later tuff rigns at Suwolbong and Songaksan(upper group) further extend the distal limb from each vent. The tuff cones and tuff rings are closely associated with the evidences which shelly fragments are comprised within them, and reworked tuffs, raised beach deposits, Sinyangri formation and littoral cones are deposited around them. The evidences suggest that the Surtseyan eruption resulted from direct or indirect interaction of magma with sea water.

• The Journal of the Petrological Society of Korea
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• v.25 no.2
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• pp.143-149
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• 2016

Eruptive volumes of three monogenetic volcanoes (Songaksan tuff ring, Biyangdo scoria cone, and Ilchulbong tuff cone) with the youngest eruption age are calculated using the model, applied to Auckland Volcanic Field in New Zealand, to investigate the volcanic eruption scale and to evaluate volcanic hazard of Jeju Island. Calculated eruptive volumes of the volcanoes are $24,987,557m^3$, $9,652,025m^3$, and $11,911,534m^3$, respectively, and the volumes include crater infill, tuff ring (tuff cone), scoria cone, and lava flow. Volcanic explosivity indices of Songaksan tuff ring, Biyangdo scoria cone, and Ilchulbong tuff cone are estimated based on the eruptive volumes to be 3, 2, and 3 respectively, and eruption type is Strombolian to Surtseyan. It is assumed that the amount of emitted sulfur dioxide gas is $2-8{\times}10^3kt/y$ according to the correlation between volcanic explosivity index and volcanic sulfur dioxide index. Recent age dating researches reveal evidences of several volcanic activities during the last 10,000 years indicating the possible volcanic eruption in Jeju Island in the near future. Therefore, it is necessary for appropriate researches regarding volcanic eruption of the island to be accomplished. In addition, establishment of the evaluation and preparation system for volcanic hazard based on the researches is required.

• The Korean Journal of Mycology
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• v.41 no.3
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• pp.181-184
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• 2013

Rhodosporidium fluviale 201-C-1 and Kluyveromyces thermotolerans 150-JE-2(1) were isolated from wild flowers in Geumsan-gun, Chungcheongnam-do and Wando-gun, Jeollanam-do, respectively. Rhodosporidium paludigenum 86-J-1 and Candida sp. 80-J-3 were also isolated from flowers in Jeju island, Korea. Characteristics for these yeasts were not reported before. Therefore, morphological and physiological characteristics for these yeasts were investigated in this study. R. fluviale 201-C-1 was halophilic asporogenous yeast and formed pseudomycelium. It also grew at $30^{\circ}C$ and pH 4.0-6.0. K. thermotolerans 150-JE-2(1) was sugar-tolerant and halotolerant asporogenous yeast. It formed pseudomycelium and showed positive urease activity. Candida sp. 80-J-3 and R. paludigenum 86-J-1 were asporogenous yeasts, and grew well in yeast extract-peptone dextrose(YPD) medium, potato-dextrose medium as well as vitamin-free medium and YPD medium containing 5% NaCl.

• Economic and Environmental Geology
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• v.54 no.2
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• pp.187-197
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• 2021

The Hyeongjeseom (Islet) is an erosional remnant of volcano which is located about 2 km northeast of sea shore of the Songaksan tuff ring, and is composed of volcaniclastic deposit, agglomerate and scoria deposit, ponded lava, aa lava flows, reworked deposit and beach deposit in ascending order from the base. The volcano is formed by volcaniclastic deposits and lava flows that recorded a transition from initial phreatomagmatic to magmatic explosions followed by lava effusion. It is interpreted that the outcropped volcaniclastic deposit may be a remaining portion of outer ring of a tuff cone. A bomb and a ponded lava yield geochemically basaltic trachyandesite compositions (SiO2 51.3 wt%, Na2O+K2O 6.0 wt%) and belong to olivine basalt with scarce (<5 %) phenocrysts of olivine, petrographically. By incremental heating Ar-Ar dating method, the plateau age of lava flow in the Heongjesom is 9.2±3.6(2σ) ka, implying that the volcanism of Heongjeseom may have occurred earlier than the Songaksan tuff ring which erupted ca. 3.7 ka. It still remains a task to find a volcano which matches with a historical record of volcanic activity that occurred a thousand years ago.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.614-620
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• 2021

Jeju has many out-of-town cultural areas owing to its low accessibility to concert halls. Based on data from Jeju in 2019, this study selected possible sites for concert halls and examined the location status of existing concert halls in Jeju by utilizing GIS analysis. As a result, directions on location selection are proposed for the western and eastern parts of Jeju, where accessibility to concert halls is relatively difficult. Considering the theory, prior research, and the regional characteristics of Jeju, the directions for location selection exclude residential areas and areas with little accessibility. They also list good points for accessibility within areas that have little of it, that are distant from administrative dong areas in Jeju-si and Seogwipo-si, that have friendly natural scenery, and that already have accessible public transportation. Accordingly, four places were proposed as possible areas for construction of a concert hall in 2020. This study is expected to contribute to cultural marketing that makes the Jeju area a Cultural Island.

• Korean Journal of Heritage: History & Science
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• v.46 no.1
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• pp.290-317
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• 2013

The objectives of this study are to investigate the natural heritage and scientific value of various geosites on Udo Island, and to evaluate the sites as natural monuments and as world natural heritage properties. Udo Island includes a variety of geoheritage sites. Various land forms formed during the formation of the Someori Oreum formed by phreatomagmatic eruptions. The essential elements for the formation of Udo Island are the tuff cone, overflowing lava and overlying redeposited tuff sediments. Various coastal land forms are also present. About 6,000 years B.C., when sea-level rose close to its present level due to deglaciation since the Last Glacial Maximum, carbonate sediments have been formed and deposited in shallow marine environment surrounding Udo Island. In particular, the very shallow broad shelf between Udo Island and Jeju Island, less than 20 m in water depth, has provided perfect conditions for the formation of rhodoids. Significant amounts of rhodoids are now forming in this area. Occasional transport of these rhodoids by typhoons has produced unique beach deposits which are entirely composed of rhodoids. Additional features are the Hagosudong Beach with its white carbonate sands, the Geommeole Beach with its black tuffaceous sands and Tolkani Beach with its basalt cobbles and boulders. Near Hagosudong Beach, wind-blown sands in the past produced carbonate sand dunes. On the northern part of the island, special carbonate sediments are present, due to their formation by composite processes such as beach-forming process and transportation by typhoons. The development of several sea caves is another feature of Udo Island, formed by waves and typhoon erosion within tuffaceous sedimentary rocks. In particular, one sea cave found at a depth of 10 m is very special because it indicates past sea-level fluctuations. Shell mounds in Udo Island may well represent the mixed heritage feature on this island. The most valuable geoheritage sites investigated around Udo Isalnd are rhodoid depostis on beaches and in shallow seas, and Someori Oreum composed of volcanoclastic deposits and basalt lava. Beach and shallow marine sediments, composed only of rhodoids, appear to be very rare in the world. Also, the natural heritage value of the Someori Oreum is outstanding, together with other phreatomagmatic tuff cones such as Suwolbong, Songaksan and Yongmeori. Consequently, the rhodoid deposits and the Someori Oreum are worth being nominated for UNESCO World Natural Heritage status. The designation of Someori Oreum as a Natural Monument should be a prerequisite for this procedure.