• 자원환경지질
• /
• 제26권4호
• /
• pp.499-505
• /
• 1993

The Imgye hornblendites occur as intrusive sills or dykes within the mylonite zone developed along the contact boundary between Precambrian Jungbongsan granite and Cambrian Jangsan quartzite or Myobong slate formations. The hornlendites belong to the subalkaline and tholeiitic series. In tectonomagmatic discrimination diagrams such as $TiO_2-K_2O-P_2O_5$, 2Nb-Zr/4-Y and $TiO_2-10MnO-10P_2O_5$, the hornblendites are classified into continental- and island-arc tholeiites. The hornblendites show fractionated REE patterns with $(La/Yb)_{CN}$ ranging from 3.73-4.56. In incompatible element abundance variations, the hornblendites show distinctive positive and negative anomalies for Rb and Nb, respectively, and unfractionated patterns of immobile incompatible elements such as Y and Yb. The REE patterns of the hornblendites are also similar to those of typical continental back-arc tholeiites and those of the Precambrian Okbang amphibolites in the Socheon-meon, Bonghwa-gun. Accoiding to geochemical characteristics above-mentioned, the hornblendites seem to have been formed from tholeiitic magmas of depleted upper mantle source, contaminated by crustal material en route to continental back-arc basin.

• The Journal of the Acoustical Society of Korea
• /
• 제22권4E호
• /
• pp.167-175
• /
• 2003

Shear wave velocity was measured and grain size analysis was conducted on two core samples obtained in unconsolidated marine sediments of the western continental margin, the East Sea. A pulse transmission technique based on the Hamilton frame was used to measure shear wave velocity. Duomorph ceramic bender transducer-receiver elements were used to generate and detect shear waves in sediment samples. Time delay was calculated by changing the sample length from the transducer-receiver element. Time delay is 43.18 μs and shear wave velocity (22.49 m/s) is calculated from the slope of regression line. Shear wave velocities of station 1 and 2 range from 8.9 to 19.0 m/s and from 8.8 to 22 mis, respectively. Shear wave velocities with depth in both cores are qualitatively in agreement with the compared model〔1〕, although the absolute value is different. The sediment type of two core samples is mud (mean grain size, 8-9Φ). Shear wave velocity generally increases with sediment depth, which is suggesting normally consolidated sediments. The complicated variation of velocity anisotropy with depth at station 2 is probably responsible for sediment disturbance by possible gas effect.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2001년도 추계종합학술대회
• /
• pp.290-294
• /
• 2001

Satellite data, with Sea Surface Temperature(SST) by NOAA and Sea Level(SL) by Topex/poseidon, are used to estimate characteristics on the variations and correlations of SST and SL in the East Asian Seas from January 1993 through May 1998. In the oceanic climate, the variations of SL shown the high values in the main current of Kuroshio and the variations of SST shown not the remarkable seasonal variations because of the continuos compensation of warm current by Kuroshio. In the continental climate, SL shown high variations in the estuaries(the Yellow River, the Yangtze River) with the mixing the fresh water in the mouth of estuaries of the saline water in the coasts of continent and SST shown highly the seasonal variations due to the climatic effect of continents. In the steric variations in summer, the eastern sea of Japan, the East China Sea and the western sea of Korea shown the increment of sea level with 10~20cm. But the Bohai bay in China shown relatively the high values of 20~30cm due to the continental climate. Generally the trends of SST and SL increased during all periods. That is say, the slopes of SST and SL presented 0.29$^{\circ}C$/year and 0.84cm/year, respectively. The annual and semi-annual amplitudes shown a remarkable variations in the western sea of Korea and the eastern sea of Japan.

• 한국지구과학회지
• /
• 제25권1호
• /
• pp.1-9
• /
• 2004

The clay minerals of thirty-four bottom sediments collected from the northwestern continental shelf of the East China Sea have been determined by X-ray diffraction analysis. The clay mineral distribution is mainly controlled by the sediment source and the dominant circulation pattern. The predominant clay mineral in our study area is illite comprising more-than 70% of whole clay fraction. The highest concentration of illite (>72%) is found in the southeastern offshore parts beyond the reach of terrigenous input from the Cheju Island. It means that these illites are largely transported by the Kuroshio Current from the South China Sea. Smectite is highly concentrated in the northwest middle part and in the outer-shelf mud patch. It seems to be due to the high supply of smectite transported from China where the fine-grained sediments are discharged from the modern and ancient Huanghe River. The relatively high abundance of kaolinite is likely derived from the Changjiang River via Taiwan ·Warm Current. In contrast, the large amounts of chlorite and high chlorite/kaolinite ratios occur in the northwestern are, reflecting the transportation by the Huanghai Sea Coastal Current from the southern Yellow Sea.

• 지구물리
• /
• 제7권4호
• /
• pp.283-291
• /
• 2004

황해안 대륙붕 지역의 Quinling-Dabie-Sulu 대륙 충돌대의 위치와 퇴적분지의 지하구조를 알아보기 위해서, 한국자원 연구원 탐해 2호에 의해서 2000년부터 2002년까지 측정된 중력 데이터에 의한3차원 지하구조 모델링을 실시한 결과, 황해안 연구지역 내의 중력 이상은 주로 퇴적층과 기반암 사이 경계면의 밀도 및 깊이의 변화에 의한 것으로 판단된다. 대륙 충돌대라고 여겨지는 고밀도 지각구조는 황해안 퇴적분지의 남쪽으로 부터 북동 방향으로 한반도의 중서부 지역으로 연결되며, 퇴적 분지 내의 현저하게 밀도가 낮은 물질의 총 부피는 약 20,000 km3 정도로 추정되었다.

• Journal of Species Research
• /
• 제13권2호
• /
• pp.159-177
• /
• 2024

A faunal study on the marine amphipods at eight sites of the continental shelf region in the Southern Sea, Korea was conducted from 16-17 August 2022. In this study, 26 amphipod species in 19 genera and 14 families were found. Among these 14 families, the family Ampeliscidae with six species showed the highest abundance, followed by the family Caprellidae with five species. Amphipods were collected using conical nets, MOCNESS nets, SM grabs, and trawls. When using the SM Grab for collecting benthic sediment, 15 out of a total of 26 amphipod species were surveyed, indicating the highest diversity of amphipod species. Out of the total 26 species, four identified species (Ampelisca pygmaea Schellenberg, 1938; Byblis longiflagelis Ren, 1998; Caprella iniquilibra Mayer, 1903; Primno latreillei Stebbing, 1888) and five unidentified species(Themisto sp., Liljeborgia sp., Dulichiella sp., Cranocephalus sp., Primno sp.) are newly recorded in Korean fauna. These newly recorded species are fully illustrated and compared with related species. We provide a list amphipod fauna in Southern Sea of Korea including figures and tables.

• 한국환경과학회지
• /
• 제20권7호
• /
• pp.829-837
• /
• 2011

A study on the grain size change, sedimentary facies and age indicator of volcanic tephra was analysis through four cores (P1 ~ P4) at the Ulleung Basin in the East Sea of Korea. The two cores (P1 and P2) were collected in the northeastern side of the Ulleung Basin (about 2,000 m in water depth), while the other two cores (P3 and P4) with the water depth of about 1,500 m and 1,700 m, respectively, were collected from the continental slope of the southwestern and western side of the Ulleung Basin. Four sedimentary facies and eight sedimentary subfacies were identified. The four facies were massive sand, bioturbated mud, homogeneous mud, and laminated mud. The eight subfacies were further divided as pumiceous ash massive sand, scorieaous massive sand, plain bioturbated mud, pyrite filamented bioturbated mud, distinctly laminated mud, indistinctly laminated mud, thinly laminated mud and homogeneous mud. The homogeneous mud was not found in the core of P3 which is located in the western side of Ulleung Basin (close to the Korean coast). In the case of laminated mud facies, the thinly laminated mud facies was dominated in the lower part of core sequences of the Ulleung Basin (P1 and P2), while the indistinctly laminated mud were overally distributed in the core sequences from the continental slope of Ulleung Basin. The Tephra layers from the core sequences of central Ulleung Basin were more dominated and distinctive than those from the core sequences of continental slope. This is related to the distance from the volcanic source and the amount of sediment supply. The core locations of Ulleung-Oki Tephra layers in the central Ulleung Basin were in the upper part of core sequences, while those in the continental slope were in the lower part of core sequences. This is indicated that the amounts of sediment supply in the continental slope after the Ulleung-Oki eruption were very high and different sedimentary environment between upper and lower of Tephra layer.

• 한국해양환경ㆍ에너지학회지
• /
• 제3권3호
• /
• pp.13-23
• /
• 2000

1993년 12원과 1994년 8월 2회에 걸쳐 동중국해 동부해역 관측선 J (30° N)의 용존무기영양염들의 분포에 대해 조사하였다. 고온고염의 특성을 지닌 쿠로시오 표층수의 질산이온 및 규산농도는 각각 2μM 이하와 5μM 이하로 낮다. 반면에 수심이 증가할수록 질산이온 및 규산농도는 급격히 증가하여 쿠로시오 중층수에서는 각각 20～40, 45～100 μM 범위로 높았다. 대륙붕역 저층수와 쿠로시오 중퐁수의 수온과 용존무기영양염 관계는 용존무기영양염이 풍부한 쿠로시오 중층수가 대륙붕수로 관입되고 있음을 암시한다. 수온, 염분 및 규산 농도를 해수추적자로 이용하여 수괴득의 혼합을 분석한 결과, 대륙붕 저층수는 대륙붕단 바로 바깥쪽 수심 약 100～400 m의 쿠로시오 중층수와의 혼합수라는 것이 밝혀졌다. 이와같이 대륙붕단을 따라 대륙사면에서 대륙붕안으로 올라오는 높은 용존무기영양염 농도를 지닌 용승해수는 동중국해 대륙붕역의 식물플랑크톤 일차생산력을 증가시키는 중요한 영양염 공급원으로 사료된다.

• 지구물리
• /
• 제9권4호
• /
• pp.443-453
• /
• 2006

남극반도 북부 남셰틀랜드군도 남서부에 위치한 스미스섬 부근 대륙주변부에서 작성된 탄성파 단면도를 분석하여 이 지역의 퇴적층의 분포, 퇴적작용, 대륙붕 형성과정 및 지체구조 발달사를 고찰하였다. 연구지역은 히어로 파쇄대의 대륙쪽 연장선에 위치한 스미스섬을 경계로 지체구조적으로 매우 상이한 두 지역으로 나눌 수 있다. 스미스섬의 남서쪽 지역은 확장중심-해구이 충돌 결과로 형성된 비활동성 대륙주변부가 전개되며, 북동쪽 지역은확장중심과 해구의 구조가 해양에 남아 있는 활동성 대륙주변부가 발달해 있다. 전체적으로 스미스섬을 경계로 북동쪽 지역에서는 두꺼운 퇴적층을 가진 대륙붕 퇴적층지역과 전호분지가 발달되어 있으며, 상대적으로 넓은 대륙사면과 뚜렷한 형태의 해구를 볼 수 있다. 남서쪽 지역은 가파르고 좁은 대륙사면과 국부적으로 형성된 대륙붕분지들이 특징적으로 나타난다. 또한 남서쪽 지역에는 이미 섭입된 확장중심의 열적효과(thermal effect)의 결과로 형성된 것으로 해석되는 기반암 상승부가 대륙붕의 중간부에 잘 발달되어 있다. 기반암 상승부는 스미스섬의 북동쪽을 연장되어 히어로파쇄대를 따라 형성된 경계부가 뚜렷한 지체구조 경계를 형성하지는 않는 것으로 해석된다.

• Ocean and Polar Research
• /
• 제31권1호
• /
• pp.31-50
• /
• 2009

The demarcation of Maritime Boundary is directly related to the expansion of jurisdiction and the securing of resources. Resource diplomacies of the three countries Korea, China and Japan represent a major task for the national administrations : to secure resources as well as to stablize and sustain resources for future national economies. At the sea area around Korea as well, countries are fiercely competing to secure resources and to expand jurisdiction. This is evidenced by the fact that various principles and logics which are beneficial to each own country are presented through international precedents, agreement between countries and the theories of the international law scholars. They say that the conclusion of demarcation of maritime boundary for the Yellow Sea would be easy from the point that there is no dispute related to island dominion in the waters of the Korean Peninsula especially the Yellow Sea, but still we need to have a strategic approach to this issue from the point that the factors used for claiming maritime boundaries may expand the waters of a country over much. For example, the continental shelf boundary in consideration of the distribution of sedimentary deposits in the Yellow Sea which is being raised by China began from the hypothesis that the inflow of sedimentary deposits to the Yellow Sea through the rivers of China represents absolute majority, but the results of the latest studies raised questions on the hypothesis. Especially, the studies done by Martin and Yang revealed that the inflow of sedimentary deposits to the Yellow Sea from the Yellow River is approximately less than 1% of total sedimentary deposits in the Yellow Sea, and also the result of analysis on the causes and counter policy measures on the environment of Bohai, China supports the reliability of the results of such studies. From a legal aspect, the sedimentary deposits of rivers which are claimed by China represent extremely weak ground for the claim for the title of the continental shelf. The siltline claimed by China seems to be based on the Article 76-4-(a)(i) of UNCLOS. This is, however, not the definition on the title of the continental shelf but it is only a technical formula to utilize in a case where a country desires to expand the continental shelf to over 200 nautical miles. Scientific and Technical Guidelines of the Commission on the Limits of the Continental Shelf also confirm this point through the Article 2.1.2 of the Guideline. The only case in which sedimentary deposits of rivers were referred to as concrete demarcation of maritime boundary was in the which was concluded in 1986 between India and Myanmar at the Andaman Sea. In the said case, India acknowledged the boundary up to the isobath of 200m which Myanmar claimed based on the sedimentary deposits of the Irrawaddy River. It has limits as a case for acknowledging the sedimentary deposits, however, because in fact India's acknowledgment was made in exchange for the condition that Myanmar gave up the dominion of two islands which they had been claiming from India up until that time.