• Title/Summary/Keyword: 층서분석

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Structure and Sequence Stratigraphy in the Southwestern Area of the South China Sea (남중국해 남서부 지역에서의 지구조 분석 및 순차층서학적 연구)

  • Lee, Eung Gyu;Lee, Gi Hwa
    • Journal of the Korean Geophysical Society
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    • v.2 no.3
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    • pp.179-190
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    • 1999
  • The overall structural framework was studied using the regional 2D seismic data, followed by the sequence stratigraphic study on the 3D seismic and well- log data in the margin of the South Con Son basin of the South China Sea. This research contributes to delineate depositional stratigraphy, depositional environment and geologic history in the 3D seismic area of highly complicated faulting. Eight Miocene sequences were indicated on the 3D seismic and well-log data, in which the structural maps of each sequence boundary and the isochron maps for the corresponding sequence were made. The seismic facies were analyzed for each sequence volume and sequence boundary surface. The 3D seismic area is characterized by coal beds deposited in the transgression environment (transgression systems tract) and channel distributions just above the sequence boundaries. During the Early Miocene, the coals and thick shales deposited in the mangrove swamp representing the lower coastal plain environment. During the Mid to Late Miocene, thick clastic sediments deposited in the coastal to shallow shelf by regional subsidence and marine transgression. The isochron maps and structural patterns indicate that the sediments were transported from west to east or from northwest to southeast.

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Depositional processes of Tidal Flat Deposits off Mankyung-Dongjin Rivers West Sea Korea. (만경강-동진강 하구역 조간대 퇴적층의 퇴적과정)

  • 최진용
    • The Korean Journal of Quaternary Research
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    • v.9 no.1
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    • pp.19-32
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    • 1995
  • 한반도 서해 만경강-동진강 하구역 조간대 퇴적층의 수직층서 퇴적상 변화를 분석 하여 퇴적과정을 기초해양환경의 관점에서 해석하였다. 본 연구해역 저 조선의 퇴적층은 사 질함량이 우세한 반면 방조제와 인접한 만조선의 퇴적층은 실트질이 우세하였고 상층과 하 층의 퇴적물이 뚜렷하게 구분되었다. 사질퇴적층의 내부퇴적구조는 괴상구조, 평행층리 및 사층리 구조등이 우세하며 니질퇴적층에서는 모래/니질 교호엽리구조가 우세하다. 본 연구 의 결과 만경강-동진강 조간대 퇴적층서는 인근의 방조제 축조에 다른 퇴적환경 변화에 크 게 영향받은 것으로 해석된다, 즉 방조제축소 이전 고에너지의 퇴적환경에서 집적되었던 사 질퇴적층이 방조제축조 이후에는 저에너지 환경조건에서 집적된 니질퇴적물로 피복된 것으 로 해석된다.

Implications on Sedimentological and Geochemical Changes in Late Quaternary Sediments and Pore Water of the Southwestern East Sea (동해 남서부 해역의 제4기 후기 퇴적물과 공극수에서의 퇴적학적 및 지화학적 변화의 의미)

  • Park, Myong-Ho;Kim, Ji-Hoon;Ryu, Byong-Jae;Lee, Song-Suk;Han, Sang-Geun;Kil, Young-Woo
    • The Korean Journal of Petroleum Geology
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    • v.12 no.1
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    • pp.20-26
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    • 2006
  • Late Quaternary stratigraphy and sedimentary environmental changes were studied based on four core sediments and their pore water taken from the southwestern part of the East Sea. The results of tephrostratigraphy and radiocarbon dates indicate that the cores cover the time interval from the middle stage of Marine Isotope Stage (MIS) 3 to MIS 1 (Holocene). The average of sedimentation rate in core sediments varies from 10 cm/kyr to 20 cm/kyr, but it fluctuates generally in particular time intervals such as MIS 2, which would be related with the sea-level changes at that time. On the other hand, the relations between ${\delta}^{13}C_{org}$ and C/N ratios suggest that the organic matter in the cores was originated mainly from marine algae. In addition, the value of ${\delta}^{13}C_{CH4}$ indicates bacterial origin rather than thermogenic one.

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Stratigraphy and Paleoenvironment of Domi-1 and Sora-1 Wells, Domi Basin (도미분지 도미-1, 소라-1공의 층서와 고환경)

  • Yun, Hye-Su;Byun, Hyun-Suk;Oh, Jin-Yong;Park, Myong-Ho;Lee, Min-Woo
    • Economic and Environmental Geology
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    • v.45 no.4
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    • pp.407-429
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    • 2012
  • There has been much debates on the geologic age of the sediments of the Domi Basin, since age results varied after research methods and fossil groups. This study carried out palynological analysis and seismic interpretation to establish a stratigraphy and environmental reconstruction mainly based on fossil dinoflagellates and Seismic data from the Domi-1 and Sora-1 wells. The dinocyst assemblages found enabled zonation of the well sediment sequence resulting in 4 ecozones. Index fossils among dinocysts and palynomorphic substances indicate geologic age of the well ranges from Eocene to Pleistocene, and paleoenvironment varies from freshwater to inner-neritic marine. The fossil association also suggests strong relationship to Japanese Tertiary basins in Kyushu area in terms of stratigraphy and basin developmental history.

Sequence Stratigraphy of Late Quaternary Deposits in the Southeastern Continental Shelf, Korea (한국 남동 대륙붕 후 제4기 퇴적층의 시퀀스 층서)

  • 유동근;이치원;최진용;박수철;최진혁
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.8 no.4
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    • pp.369-379
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    • 2003
  • Analysis of high-resolution seismic profiles and sediment data from the southeastern continental shelf of Korea reveals that the late Quaternary deposits consist of a set of lowstand (LST), transgressive (TST), and highstand systems tracts (HST) that corresponds to the sea-level change after the Last Glacial Maximum. LST (Unit I) above the sequence boundary consists of sandy mud or muddy sand deposited during the last glacial period and is confined to the shelf margin and trough region. TST (Unit II) between transgressive surface and maximum flooding surface consists of sandy sediments deposited during the postglacial transgression (15,000-6,000 yr BP). Although TST is widely distributed on the shelf, it is much thinner than LST and HST. On the basis of distribution pattern, TST can be divided into three sub-units: early TST (Unit IIa) on the shelf margin, middle TST (Unit IIb) on the mid-shelf, and late TST (Unit IIc) on the inner shelf, respectively. These are characterized by a backstepping depositional arrangement. HST(Unit III) above the maximum flooding surface is composed of the fine-grained sediments deposited during the last 6000 yrs when sea level was close to the present level and its distribution is restricted to the inner shelf along the coast.

Stratigraphy of the Kachi-1 Well, Kunsan Basin, Offshore Western Korea (한국 서해 대륙붕 군산분지 까치-1공의 층서)

  • Ryu, In-Chang;Kim, Tae-Hoon
    • Economic and Environmental Geology
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    • v.40 no.4
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    • pp.473-490
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    • 2007
  • Strata of the Kachi-1 well, Kunsan Basin, offshore western Korea, were analyzed by using integrated stratigraphy approach. As a result, five distinct unconformity-bounded units are recognized in the well: Triassic, Late Jurassic-Early Cretaceous, Early Cretaceous, Late Cretaceous, and Middle Miocene units. Each unit represents a tectono-stratigraphic unit that provides time-sliced information on basin-forming tectonics, sedimentation, and basin-modifying tectonics of the Kunsan Basin. In the late Late Jurassic, development of second- or third-order wrench faults along the Tan-Lu fault system probably initiated a series of small-scale strike-slip extensional basins. Continued sinistral movement of these wrench faults until the Late Cretaceous caused a mega-shear in the basin, forming a large-scale pull-apart basin. However, in the Early Tertiary, the Indian Plate began to collide with the Eurasian Plate, forming a mega-suture zone. This orogenic event, namely the Himalayan Orogeny, continued by late Eocene and was probably responsible for initiation of right-lateral motion of the Tan-Lu fault system. The right-lateral strike-slip movement of the Tan-Lu fault caused the tectonic inversion of the Kunsan Basin. Thus, the late Eocene to Oligocene was the main period of severe tectonic modification of the basin. After the Oligocene, the Kunsan Basin has maintained thermal subsidence up to the present with short periods of marine transgressions extending into the land part of the present basin.

오일샌드 저류층 지질특성화를 위한 기초연구 소개

  • Choe, Jae-Yong;Kim, Dae-Seok;Gwon, Lee-Gyun;Jeong, Gong-Su
    • 한국지구과학회:학술대회논문집
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    • 2010.04a
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    • pp.106-106
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    • 2010
  • 오일샌드는 비투멘(bitumen), 물, 점토, 모래의 혼합체로 이루어진 비재래형 탄화수소 자원으로 세계적인 고유가 시대에 큰 관심을 받고 있는 석유자원 중 하나이다. 오일샌드는 대부분이 캐나다 앨버타주에 분포하고 있으며 주요 저류층으로는 아스바스카(Athabasca), 콜드레이크(Cold Lake) 지역의 멕머레이층(McMurray Formation), 클리어워터층(Clearwater Formation), 그랜드래피드층(Grand Rapid Formation)과 피스리버(Peace River) 지역의 블루스카이층(Bluesky Formation), 게팅층(Gathing Formation)이 있다. 오일샌드 저류층은 고생대 탄산염 기반암 위에 하성-에스츄어리에 이르는 다양한 퇴적환경에서 형성되어 매우 복잡한 지질특성이 나타난다. 오일샌드 저류층의 효율적인 개발을 위해서는 저류층의 복잡한 지질학적 특성의 이해가 반드시 필요하다. 본 연구에서 캐나다 오일샌드 시추코어 분석 DB, 물리검층 자료, 현장 및 현생 시추코어를 통하여 오일샌드 저류층의 지질특성화 정보의 도출을 시도하였다. 우선 캐나다 앨버타 전역에 분포하는 시추공의 기본 정보(표고, 위경도, 층서별 최상부 심도, 생산광구명, 광구개발업체)를 제공하는 AccuMap DB 프로그램을 이용하여 광역적인 오일샌드 저류층의 분포 특성을 이해하고자 주요층서에 대한 고지형도 및 층후도를 생산광구별로 도면화하여 분석하였다. 또한 캐나다 ENCANA사와 국제공동연구의 일환으로 확보된 크리스티나 레이크(Christina Lake)광구의 현장 시추코어를 이용하여 코어의 상세기재, 비파괴 물성측정, 입도/비투멘 함유량 분석과 같은 다양한 실내 시추코어분석 실험을 수행 중이다. 비파괴 물성측정은 현장 시추코어의 물리적/화학적 특성을 파악하고자 MSCL(Multi sensor core logger)과 XRF 코어 스캐너(X-ray fluorescence core scaner)를 통해 이루어지며, 분석결과로 시추코어의 감마밀도(gamma density), P파 속도(P-wave velocity), 전기비저항(resistivity), 대자율(magnetic susceptibility) 및 색지수의 물성과 정량적 화학조성을 측정한다. 현장 시추코어의 일부는 유기용매를 이용하여 퇴적물 내의 비투멘을 완전히 추출하고 퇴적물 입도와 저류층 비투멘 함유량 측정에 이용되었다. 현장 시료 분석 결과들은 물리검층 자료와 대비를 통하여 저류층의 지질특성을 규명하는 연구에 이용될 예정이다. 마지막으로 오일샌드의 현생 유사 퇴적환경으로 알려진 서해 경기만 조간대에서 시추코어 퇴적물을 획득하여 상세 기재하였으며, 이를 통해 오일샌드 저류층의 퇴적 모델을 제시하고자 퇴적층서 연구를 진행 중이다. 향후 오일샌드 관련 시추코어의 분석 결과들이 종합되면 기존 보다 비투멘 회수효율을 향상시킬 수 있는 정밀한 오일샌드 저류층 지질모델을 수립할 수 있을 것으로 기대된다.

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Late Quaternary Stratigraphy and its Depositional History in the Inner Shelf off the Southern Coast, Korea (한국 남해 내 대륙붕 후 제4기 층서 및 퇴적역사)

  • Yoo, Dong-Geun;Lee, Ho-Young;Park, Keun-Pil;Koo, Nam-Hyung;Kim, Jong-Chon
    • Geophysics and Geophysical Exploration
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    • v.8 no.4
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    • pp.243-250
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    • 2005
  • Analysis of high-resolution seismic profiles acquired from the inner shelf off the southern coast of Korea reveals that the inner shelf sequence can be divided into three stratigraphic units formed after the Last Glacial Maximum (LGM). Unit I is characterized by complex seismic facies including semi-transparent, stratified, and hummocky reflections on seismic records. It consists of sandy mud or muddy sand, deposited under estuarine environment during the post-glacial transgression. Unit II acoustically shows semi-transparent or hummocky reflections and consists of sand with gravels and shell debris, produced by shoreface erosion during the transgression. Unit III is characterized by transparent or semi-transparent seismic facies and consists of mud originated from the Nakdong and Seomjin rivers during recent highstand of sea level. Unit III is confined to the inner shelf with an extenal form of stratal wedge.