• 제목/요약/키워드: GEOLOGICAL HISTORY

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Deep-sea Hydrothermal Vents: Ecology and Evolution

  • Won, Yong-Jin
    • Journal of Ecology and Environment
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    • 제29권2호
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    • pp.175-183
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    • 2006
  • The discovery of deep-sea hydrothermal vents and their ecosystems is a monumental landmark in the history of Ocean Sciences. Deep-sea hydrothermal vents are scattered along the global mid-ocean ridges and back-arc basins. Under sea volcanic phenomena related to underlying magma activities along mid-ocean ridges generate extreme habitats for highly specialized communities of animals. Multidisciplinary research efforts during past three decades since the first discovery of hydrothermal vents along the Galapagos Rift in 1977 revealed fundamental components of physiology, ecology, and evolution of specialized vent communities of micro and macro fauna. Heterogeneous regional geological settings and tectonic plate history have been considered as important geophysical and evolutionary factors for current patterns of taxonomic composition and distribution of vent faunas among venting sites in the World Ocean basins. It was found that these communities are based on primary production of chemosynthetic bacteria which directly utilize reduced compounds, mostly $H_2S$ and $CH_4$, mixed in vent fluids. Symbioses between these bacteria and their hosts, vent invertebrates, are foundation of the vent ecosystem. Gene flow and population genetic studies in parallel with larval biology began to unveil hidden dispersal barrier under deep sea as well as various dispersal characteristics cross taxa. Comparative molecular phylogenetics of vent animals revealed that vent faunas are closely related to those of cold-water seeps in general. In perspective additional interesting discoveries are anticipated particularly with further refined and expanded studies aided by new instrumental technologies.

동해 울릉도-독도 화산그룹 분화사 다중스케일 연구 (Eruptive History of the Ulleungdo-Dokdo Volcanic Group, the East Sea: a Multi-Scale Approach)

  • 김기범;이재혁;안호준;제윤희
    • 한국지구과학회지
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    • 제43권1호
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    • pp.140-150
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    • 2022
  • 이 논문은 울릉도, 독도를 포함하는 동해 울릉분지 해저 화산그룹(가칭: 울릉도-독도 화산그룹)의 분화사를 복원하고 미래 분화 가능성을 평가하기 위해 진행중인 육상-해양 복합 다중스케일 화산연구의 개념과 지금까지의 결과를 소개하는데 목적을 둔다. 다중채널 탄성파반사자료 해석을 통해 유추되는 울릉도-독도 화산그룹의 주 활동 시기는 대략 5-2.5 Ma로, 동쪽 끝의 이사부평정해산에서 처음 시작되어 서쪽의 울릉도로 전파된 것으로 해석된다. 울릉도의 육상부는 5단계에 걸쳐 생성되었으며 최종 단계에 접어들어 폭발성 분화를 통해 폭 약 3 km의 칼데라 지형과 그 내부에 화산돔을 형성하였다. 울릉도의 마지막 분화 산물인 알봉 화산돔과 그 하부의 수증기마그마성 분화로부터 기원된 층단위 N-1 화산쇄설층은 기존 포놀라이트질 마그마방으로 유입된 보다 염기성의 새로운 마그마의 분화로부터 생성되었다. 층단위 N-1과 알봉 분석이 갖는 조면안산암질 전암조성은 기존 포놀라이트질 마그마방 하부에 존재한 고철질 집적암이 새로 주입된 마그마를 오염시킨 결과로, 그 자체가 마그마의 조성을 지시하지는 않는다. 층단위 N-1과 알봉 화산돔에서 확인되는 새로운 마그마 주입의 증거들은 최근 밝혀진 울릉도의 높은 지온구배 및 분화주기와 더불어 울릉도가 여전히 작동중인 마그마 배관체계를 갖는 활화산임을 암시한다.

원생대 하동회장암체 내 철-티탄 광체의 산상과 변형 (Occurrence and Deformation of Fe-Ti ores from the Proterozoic Hadong Anorthosites, Korea)

  • 정재성;김종선;조형성;송철우;손문;류충렬;지세정;김인수
    • 암석학회지
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    • 제19권1호
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    • pp.31-49
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    • 2010
  • 한반도 남부 원생대 하동회장암체 내에는 주변 회장암의 암상과 무관하게 대략 남북방향으로 단속적으로 철-티탄 광체들이 출현한다. 이들 광체의 야외산상과 변형사를 밝히기 위하여 야외기재학적 특징과 주변 지질구조 분석 그리고 주요 암석과 광체 내 티탄철석에 대한 박편관찰과 전자현미분석을 실시하였다. 이번 연구의 대상 광체는 맥상과 층상 광체로 구분된다. 맥상 광체는 회장암체가 정치 고화된 이후에 관입하였음이 확실시되며, 층상 광체는 후기의 강력한 우수향 연성 전단작용에 의해 상대적으로 규모가 큰 맥상 광체가 압쇄암화 되고 전단엽리와 평행하게 전위된 결과로 해석된다. 철-티탄 광체는 청룡리, 월횡리, 종화리, 자양리와 백운리의 순서로 남에서 북으로 갈수록 후기 우수향 연성 전단변형을 많이 받았으며, 광체 내 티탄철석의 함량은 감소하는 특징을 보인다. 광체 내 티탄철석은 야외산상과 후기 전단변형의 정도와 무관하게 유사한 화학조성을 가지며, $TiO_2$ 함량이 52~55 wt.% 내외로 자철석으로 용리되지 않은 순수한 티탄철석의 화학조성을 보여준다. 야외 지질구조 자료들을 분석하면, 하동회장암체는 마그마의 분화작용으로 만들어진 누적 엽리의 생성 이후에 북북동-남남서 습곡, 철-티탄 광체의 관입, 북북서~북북동 우수향 연성 전단작용, 북서~북북서 좌수향 아취성 전단작용, 그리고 북북동~북동 방향의 염기성 마그마의 관입의 순서로 변형된 것으로 판단된다.

화산위험지도의 역사 (The History of Volcanic Hazard Map)

  • 윤성효;장철우
    • 암석학회지
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    • 제27권1호
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    • pp.49-66
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    • 2018
  • 화산위험지도 작성은 1960년대 과학 탐구의 초점이 되었다. Dwight Crandell과 Don Mullineau는 '과거는 미래의 열쇠이다'라는 관점으로 재해위험 매핑에 대한 지질학적 접근 방법을 개척했다. 세인트 헬렌즈산의 위험도 평가와 가까운 미래의 분출 예측에 대한 1978년 발간물, 그리고 1980년 대규모 분화로 화산위험 평가의 유용성이 입증되었고 화산 과학의 이 영역에서 거대한 성장이 시작되었다. 1980년대의 위험한 지역을 식별하기 위해 위험지역 이해 프로세스의 수치 모델을 개발하고 사용하기 시작했으며, 1990년대 후반부터 확산되었다. 수치모의 모델 산출물은 화산의 지질학적 지식에 의해 강조될 때 가장 유용하고 정확하다. 화산위험지도는 장기간의 무조건적인 화산 재해 위험을 묘사하는지, 어느 정도의 위험을 가진 모든 지역을 보여주는지, 화산이 불안정 또는 분화 위기 시에 개발되어 현재의 감시, 관찰 및 예보 정보를 고려한 지도로 크게 분류할 수 있다.

승광선사탑(乘廣禪師塔)를 통한 팔각정형(八角亭形) 승탑사(僧塔史)의 재고(再考) (Referring to The Stupa of Master ChengGuang, Reconsideration of the History of Buddhist Monks' Octagonal Tempietto Shaped Stupa)

  • 황문호
    • 건축역사연구
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    • 제28권1호
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    • pp.25-34
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    • 2019
  • "Stupa of Buddhist Monk, YeomGeo"(844) is known as the earliest Seon-stupa relic remains in Korean peninsula, from which, during late Silla and ealy Goryeo period, there were more than 30 of stupa was built on such canon. and became the well-known material culture in Seon Buddhism in late Silla period. In $9^{th}$ century, with the JeonDeong(delivering the light of Seon)from Tang to Silla, the culture of "GeonTapIpBi(building the pagoda and erecting stele)" was also moved in. And it was right after the style of monk's stupa had been methodically changed in china, from having the room in stupa for the corpse, named as "QuanShenSheLi", to the lessened stupa that contain the cremated. Analyzing the "Master ChengGuang's stupa"(807)and its stele, it can be found the correspondences of octagonal plan and the subjects of ornamentation to that of Stupas built in Silla, reveals they were made by the same canon. By the document in the stele, surmising the historical cause of alteration in Chan stupa, there was the most famous zen master ShenHui at the time, who has the most important role of making the NanZongChan to get the authenticity in Chan Buddhism. His reliqury was the first ${\acute{s}}ar{\bar{i}}ra$ casket discovered among Chan monks' relics, consequentially it was to influence to Chan cuture and size the monks 'stupa for his ${\acute{s}}ar{\bar{i}}ra$. The stupa of master ChengGuang, by its shape and geological location, is the lost piece in the Puzzle of Chan stupa culture between Silla and Tang.

하이드레이트 함유 퇴적물의 역학적 성질 및 지구물리 특성 (Mechanical and Electrical Properties of Hydrate-bearing Sediments)

  • 이주용
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2007년도 추계학술대회 논문집
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    • pp.594-596
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    • 2007
  • Using an oedometer cell instrumented to measure the evolution of electromagnetic properties, small strain stiffness, and temperature, we conducted consolidation tests on four types of sediments. The tested specimens include sediments with different gas hydrate saturation at four stages of loading. The test results show that the electromagnetic and mechanical properties of hydrate-bearing marine sediments are governed by the vertical effective stress, stress history, porosity, hydrate saturation, fabric, ionic concentration of the pore fluid, and temperature. The results also show that permittivity and electrical conductivity data can be combined to estimate hydrate volume fraction in laboratory sediments, methodology that might eventually be extended for estimation of hydrate concentrations in field settings.

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Investigation of possible causes of sinkhole incident at the Zonguldak Coal Basin, Turkey

  • Genis, Melih;Akcin, Hakan;Aydan, Omer;Bacak, Gurkan
    • Geomechanics and Engineering
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    • 제16권2호
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    • pp.177-185
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    • 2018
  • The subsidence mechanism of ground surface is a complex phenomenon when multiple seam coal mining operations are carried out. Particularly, the coal mining beneath karstic formations causes a very special form of subsidence. The subsidence causes elasto-plastic deformation of the karstic layers and the collapse of cavities leads to dolinization and/or sinkhole formation. In this study, a sinkhole with a depth of 90 m and a width of 25 m formed in Gelik district within the coal-basin of Zonguldak (NW, Turkey) induced by multiple seam coal mining operations in the past has been presented as a case-history together with two-dimensional numerical simulations and InSAR monitoring. The computational results proved that the sinkhole was formed as a result of severe yielding in the close vicinity of the faults in contact with karstic formation due to multiple seam longwall mining at different levels.

Linzhi Native Pig - An Investigation Report on New Genetic Resource of Livestock

  • Chang, H.;Mimachiren, Mimachiren;Li, X.Y.;Ren, Z.J.;Dongwang, Dongwang;Dejiyangzhong, Dejiyangzhong;Chang, G.B.
    • Asian-Australasian Journal of Animal Sciences
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    • 제14권9호
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    • pp.1203-1208
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    • 2001
  • Linzhi Native Pig is a unique local breed recently discovered in the hinterland of Tibet. Its geological distribution, natural environment and ecological conditions have been explored. Using random sampling in typical colony of classification and standard animal-scientific and biogenetic techniques, we examined its contour features, size and weight, reproductive performances, carcass characters, meat quality, fresh-keeping features and the frequency distribution in the 19 structural gene loci encoding enzymes and proteins; according to folklores and Tibetan, Chinese and English history books, the materials and literature of Tibetan Studies, we have analyzed its origin and affirmed the fact that its products have been consumed as Tibetan medicine resources. Our findings make certain that Linzhi Native Pig holds great potential value in economy and culture.

강화도 동막해변의 지질명소로서 가치와 증진 방안에 관한 연구 (A Study on the Values Of Dongmag Beach as a Geosite and Increasing its Values)

  • 박경
    • 한국지형학회지
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    • 제25권4호
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    • pp.117-129
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    • 2018
  • Dongmag beach area contains diverse geological and geomorphological outcrops which can be used for geotourism purposes. They are as follows; headland with granodiorite with plenty of enclaves and sandy beach, which is fed from Manisan with well-developed sheeting joints composed of granite and granodiorite. Weathered material from the hillside feedsthe one and only sandy beach in Ganghwado Island. Weathered outcrop at the hillside behind beach exposes typical spherical weathering also. Bunori Dondae Fort which was built on top of sea cliff with granodiorite has plenty of history and cultural values commands an extraordinary view of tidal flats and coastal landforms. This geosite with high geodiversity can be used for interpreters who provide balanced views of nature conservation.

Spore-Pollen Specters of Deed Turnn Lake Terrace, Darkhad Depression, Mongolia

  • Punsalpaamuu, G.
    • 한국제4기학회지
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    • 제17권2호
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    • pp.39-41
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    • 2003
  • Pollen and spores as well as their morphological characteristics are biological stability materials in which contains historical information about vegetation and climate changes. As noted researcher Neishtadt in 1971, the lake and swamp deposits were developed only in Holocene period. The geological history of Darkhad depression which is situated in the Northern end of Mongolia from ancient time become under scientific interest of many researchers. Our investigation was focused on pollen analysis of lake sediment of Darkhad depression which caused bottom of paleolake. In Mongolia the palynology science is beginning to develop since 1990 and in 2000 the laboratory of palynology was established at the department of Biology, State Pedagogical University of Mongolia. Researchers from this laboratory working on pollen morphology of present flora in order to classify plants taxonomy. Another part of our investigation is mellitopalynology, which is studying of pollen grains in a honey. Although, this research has been extending by pollen analysis of sediment and lake deposits in past few years on the basis of high sensitive microscope and modem technology.

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