• The Journal of the Petrological Society of Korea
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• v.25 no.4
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• pp.335-348
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• 2016

The fluvial Tamna Formation, consisting of conglomerate, sandstone and mudstone layers, is widely distributed in Jeiu Island. Various sizes of quartz crystals were identified from most of the Tamna Formation, including the mudstone layer. XRD analysis also shows that the mudstone layer is composed of various minerals, quartz, plagioclase, K-feldspar, mica, magnetite, hematite, olivine, amphibole, gibbsite, calcite, analcime and clay minerals such as illite, kaolinite, vermiculite, smectite, chlorite, $10{\AA}$-halloysite. There is a tendency showing that the more amount of kaolinite, vermiculite, and chlorite is present where the more amount of quartz crystals is present. It is likely that the main source materials contributing to the Tamna Formation were from the parental rocks containing abundant quartz grains, suggesting that the Tamna Formation could not be related to Jeju volcanic rocks, but possibly to pre-existing basement rocks. Thus, we propose that the Tamna Formation was formed from the materials derived from both pre-existing basement rocks and Jeju volcanic rocks, which were subsequently affected by diagenesis, hydrothermal alteration and weathering process.

• Journal of Environmental Science International
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• v.12 no.7
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• pp.753-762
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• 2003

Butyltin compounds (BTs), namely tributyltin (TBT), dibutyltin (DBT) and monobutyltin (MBT), were measured in surface sediments collected in 2001 inside Hallim Harbor where a lot of shipping occurs as one of major harbors of Jeju Island, in order to evaluate their distribution. BTs were detected in surface sediments of all stations and their concentrations were comparable to those in surface sediments of other sites of domestic and foreign countries. The main species among BTs was MBT, although there was a little difference with a survey site. No correlations were obtained between organic matter or particles size of surface sediments and total BTs, indicating that these factors did not affect on the distribution of BTs. It was estimated that more complex factors including BTs loads and surrounding sedimentary environments, affected on the distribution of BTs. The high correlations between BTs indicated that DBT and MBT were mainly degraded from TBT based on antifouling paints of vessel etc. and other sources, such as DBT and MBT, could be ignored. The butyltin degradation indexes ([DBT] + [MBT]/[TBT]) Ivere in the range of 1.5∼3.3 (mean 2.5), indicating that the parent compound, TBT, were inflowed into the surface sediments a long years ago and degraded.

• Proceedings of the KSRS Conference
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• 2006.03a
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• pp.91-94
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• 2006

China Coastal Waters (CCW) usually appears in the seas surrounding Jeju Island annually(June to October) and is very pronounced in August. Generally, low-salinity water appears to the western seas of Jeiu Island from June through October and gradually propagates to the eastern seas, where CCW meets the Tsushima Current. Empirical orthogonal function (EOF) analysis of SLAs and SSTs indicated that the valiance in SLAs and SSTs was 95.05%(the first mode to third mode) and 98.09%(the first mode), respectively The PSD of the western waters for the first mode of EOF analysis of SLAs was stronger than that of the eastern waters because of the influence of CCW. The PSD for the EOF analysis of SSTs was similar in all areas (the Yangtze Estuary and the seas to the west and east of Jeju Island), with a period of approximately 260 days.

• Korean Journal of Plant Resources
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• v.14 no.3
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• pp.277-285
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• 2001

This study was conducted to know about the distribution of naturalized plants growing in Jeiu Island. A field survey and flora lists of relevant literatures were also investigated. The results obtained from this study were as follows: Definition of naturalized plants was determined in this study as “non-native species in Korea which have been introduced anthropologically or naturally and can reproduce and survive in wild habitats by themselves.” It was suggested that the number of naturalized plants in Jeju Island were 31 families, 111 genera, 188 taxa including 178 species, 10 varieties. Family Compositae and Gramineae covered 23% and 14% of naturalized plants, respectively. The number of naturalized plants in Jeju Island were 188 taxa ; 97 taxa in the whole south Korea,39 taxa in the southern part of Korea,15 taxa in the central part of Korea, and 37 taxa only in Jeju.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2006.04a
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• pp.293-296
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• 2006

본 연구에서는 Landsat 7 ETM+위성영상을 이용하여 제주도의 표면온도분포를 구하여 제주도의 식생 분포와 비교해 보았다. 계산결과 온도분포는 제주의 남쪽지역이 북쪽보다 약$3^{\circ}C$정도 높게 나타났으며, 이러한 온도분포로 인하여 제주도의 남쪽에는 활엽수가 북쪽보다 침엽수가 대체적으로 많이 분포하였으며, 나무의 성장과 관련된 나무목의 둘레가 대체적으로 굵게은 것으로 나타났다. 이러한 경향으로 보아 제주도의 경우 같은 고도의 남쪽과 북쪽의 온도분포가 다르게 나타나며, 이러한 영향으로 인해 한라산 식생분포특성이 달라지는 것으로 판단되었다.

• Journal of the Korean Society for Marine Environment & Energy
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• v.4 no.3
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• pp.53-64
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• 2001

Bathing beach may be one of the ocean resorts in popular, which peoples can easily access in summer. Three beaches in Jeiu island are surveyed about natural environmental conditions using coastal engineering technique and questionnaire are carried out. Also the satisfaction index on the sand size, wave height, water temperature, transparency and bottom slope is gained very well. The results obtained from this study can be utilized making a new artificial bathing beach in the future.

• Korean Journal of Environment and Ecology
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• v.19 no.4
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• pp.342-347
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• 2005

This study was carried out to examine the distribution and habitat of Bibarl snake (Sibynophis Collaris) from March 1998 to June 2005 in Jeju island, Korea. 5 individuals of Bibari snake were observed on northern part of JeJu, 1 individual on southern area and 2 individuals on western area during research period. As a result, it was revealed that Bibari snake was found on the whole of Jeju island. Its observation was made from May to October, especially frequent from May to July. The body length of adult Bibari snakes were $406{\~}452mm$ and its tail length $29+{\~}202mm. Considering of number and shape of supralabials and number of temporals, the characters of Bibari snake were similar to those of S. chinensis. Therefore it seems need to reconstruct taxonomic position of Bibari snake. From a vertical viewpoint of Mt. Halla, Biabri snake prefers to stay on the grassland 600m below the sea. Consequently, it Is suggested that grassland be well-reserved for the protection of Bibari snakes.

• Journal of the Korean earth science society
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• v.27 no.5
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• pp.579-584
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• 2006

A fossil feather found from the Late Pleistocene sediments of Jeju Island, Korea is described. The sediments deposited in a shallow marine environment yielded numerous footprints of diverse birds and mammals including hominids. A fossil feather well-preserved as a thin white film on the light gray mudstone is part of a vaned flight one. Although the specimen is relatively small in size (10.3 mm long and 9.0 mm wide), a rachis with two flat vanes and nearly parallel curved barbs with numerous proximal and distal barbules are well preserved. The specimen represents the first record of a fossil feather from Korea and is also the first record of feather from the Pleistocene deposits in the world.

• Journal of the Korean Geographical Society
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• v.43 no.4
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• pp.466-476
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• 2008

Gurin Cave, 442 m long, is a lava tube developed on the northern slope of Mount Halla. Seventy-three meters of its lower reach became a river channel since Byeongmun River flowed into a window after roof collapse took place. The subterranean channel has a width of 447 cm and a height of 501 cm, respectively. Its banks show well-developed lava shelves of a typical lava tube, while its floor has sculpted forms which characterize a bed of a bedrock stream. The reach is likely to be collapsed and then has four collapsed windows since its roof has the densely developed testudinal joints and consists of thin lavas with a thickness of 30 to 60 cm. Before the subterranean channel appeared, a ground channel flowed over the cave and joined into a main channel of Byeongmun River at 653 m in altitude. However, the subterranean channel substituted the ground channel since a bed of the ground channel collapsed into the cave. The new channel, flowing through the cave, joined into a main channel at 660 m in altitude. As the drainage area of Byeongmun River expanded upstream the cave, the new channel changed into a main channel. Since floodwater flows down the ground channel as well as the subterranean channel, a distributary stream has temporarily appeared at the collapsed window. Lava tubes are likely to have an affect on the development of river system in Jeiu Island, in that the caves have constantly shown roof-fall.

• Journal of the Korean earth science society
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• v.28 no.7
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• pp.925-935
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• 2007

Water sources in volcanic Jeju Island are almost entirely dependent on groundwater because there are actually no perennial streams or rivers due to the permeable nature of surface soils derived from basaltic or trachytic rocks. Uncontrolled development of groundwater resulted in substantial water-level decline, groundwater pollution, and seawater intrusion in several places of the island. To maintain its sustainable groundwater, the provincial government has declared some parts of the island as the Special Groundwater Conservation/Management Area since 1994. Hence, all the activities for the groundwater development in the area should obtain official permit from relevant authorities. Furthermore, to acquire information on groundwater status, a network of groundwater monitoring was established to cover most of the low land and coastal areas with the installation of automatic monitoring systems since 2001. The analysis of the groundwater monitoring data indicated that the water levels had decreased at coastal area, especially in northern part of the island. Moreover, very high electrical conductivity (EC) levels and their increasing trends were observed in the eastern part, which was ascribable to seawater intrusion by intensive pumping in recent years. Water level decline and EC rise in the coastal area are expected to continue despite the present strict control on additional groundwater development.