• 제목/요약/키워드: Sedimentary

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Age and Stratification of Dinosaur Eggs and Clutches from Seonso Formation, South Korea

  • Kim, Cheong-Bin;Kim, Jeong-Min;Huh, Min
    • Journal of the Korean earth science society
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    • v.29 no.5
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    • pp.386-395
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    • 2008
  • The absolute age of lapilli tuff in sedimentary formation that contains dinosaur fossils in the Boseong area, Korea was determined radiometrically against volcanic rocks below and above the fossil-bearing horizons. The sanidine in the lapilli tuff below the fossil-bearing horizon (Seonso formation) has an $^{40}Ar-^{39}Ar$ age of $81.l{\pm}1.4Ma$. The Pilbong tuff above Seonso formation has an $^{40}Ar-^{39}Ar$ age of $81.0{\pm}2.4Ma$. An andesite dyke intruding all sedimentary units yields an $^{40}Ar-^{39}Ar$ age of $42.4{\pm}2.5Ma$. Thus 81 Ma age can be regarded as the best estimate for the age of the Seonso Formation and the associated the dinosaur eggs. This age correlates well with dinosaur fossil finds in the Haenam and Koseong regions of Korea. The occurrence of dinosaur eggs and clutches attests to the existence of dinosaurs in southern Korea at least inCampanian times.

Characteristics of the Sedimentary Environment in Yoja Bay in the Summer of 1998 (1998년 하계 여자만의 저질환경 특성)

  • 허회권;김도현;안승환;박경원
    • Korean Journal of Environmental Biology
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    • v.18 no.2
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    • pp.227-235
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    • 2000
  • As a part of basic investigation to Fishery Purge Project for the Special Administrative in Chollanamdo Province, the sedimentary environmental characteristics of Yoja Bay at 15 stations were studied. The analysis was carried out in July, 1998, through studies of Loss On Ignition (LOI) by depth, Total Sulfide (T-5), Chemical Oxygen Demand (COD) concentrations and Grain-size distribution. The LOI value was found to be 6.20-12.20% (mean of 8.89%), with the neighboring Sunhakri and Haksanri areas showing slightly higher values. These values were similar to the LOI values observed in the Hansan-Koje Bay and Jinju Bay areas on the southern coast of Korea. T-S and COD concentrations were found to be, respectively, 0.060-0.104 mg/gㆍd (mean of 0.052 mg/gㆍd) and 5.53-29.71 mg/gㆍd(mean of 13.24 mg/gㆍd), not exceeding eutrophication limits. T-S concentration was especially high at stations close to the central areas of the bay and inland areas, which caused by organic matter input from the nearby agricultural areas. COD concentration was very high at stations nearby the bay entrance and Doonbyungdo, but the mean value was lower than that of Hansan-Koje Bay. This leads us to believe that the level of pollution in Yoja Bay is not significant. The prevailing sediment composition was mud, consisting of 61.38% silt and 34.87% clay. [Sediments in Yoja Bay, Loss On Ignition, Total Sulfide, Chemical Oxygen Demand, Grain-Size Distribution].

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The Depth and Configuration of The Basement at Sokotra Basin, Offshore Korea Using Marine Magnetics

  • Suh Mancheol;Abdallatif Tareq F.;Han Jungsik;Choi Sungho
    • 한국지구물리탐사학회:학술대회논문집
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    • 2004.06a
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    • pp.165-169
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    • 2004
  • Marine magnetic survey were carried out at Sokotra Basin offshore Korea between latitudes $31^{\circ}$ 42'32' N and $32^{\circ}$ 46'29' N, and longitudes $123^{\circ}$ 56'26" E and $125^{\circ}$ 49'16" E in order to estimate the depth of basement complex and as well as to configure it surface and produce the thickness of sedimentary sequence at the study area. Two methods have been used for depth estimation and basement configuration: the power spectrum and the 3-D analytical signal. The estimated depths resulted from the power spectrum method range from 1.4 km to 6.0 km for deep sources (basement troughs), and from 0.3 km to 1.75 km for shallow source (basement peaks). An isopach map was prepared for estimating the thickness of the sedimentary sequence at the study area; it ranges from 1.2 to 4.66 km. The estimated depths resulted from the analytic signal method range from 1.0 to 6 km. A basement configuration map was constructed for the study area in the basin. They show a well agreement with the geology of the study area.

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An Engineering Survey and Proposal on Preservation of Petrograms at Daegok Brook (대곡천 암각화군의 공학적 진단과 보존방안의 제안)

  • Cho, Hong-Jae;Moon, Jong-Kyu
    • Tunnel and Underground Space
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    • v.20 no.3
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    • pp.194-206
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    • 2010
  • It has been presumed that Bangudae-petrogram and Chunjonri-petrogram have been sculptured along the river Taewha in the prehistoric age. These petrograms have been sculptured on shale, the sedimentary rock of cretaceous in Mesozoic era and have been weathered by wind and rain for around 6000 years, resulting in weathering grade 5. Specially, Bangudae-petrogram has been in submerged zone in Sayeon dam for 168 days a year and the submersion has been repeated for 45 years up to date. This paper adopts an engineering approach to these petrograms' properties and discuss how to enhance strengths of petrograms themselves and stop weathering.

A comparison between organic matters and sedimentary facies in the Ulleung Basin, East Se (동해 울릉분지의 퇴적상과 유기물 특성 대비)

  • Chun, Jong-Hwa;Kwon, Young-Ihn;Kim, Ji-Hoon;Kim, Hag-Ju;Ryu, Byoung-Jae;Son, Byeong-Kook;Lee, Young-Joo;Lee, Ho-Young
    • 한국신재생에너지학회:학술대회논문집
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    • 2007.06a
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    • pp.504-506
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    • 2007
  • 동해 울릉분지에서 채취된 피스톤 코어 시료의 퇴적상과 유기물 특성을 대비하였다. 코어 시료의 퇴적상은 크게 홀로세 생물교란된 뻘 퇴적상과 빙하기의 다양한(생물교란된, 엽리가 발달된) 뻘 퇴적상으로 구분되었다. 코어 시료의 유기물 특성은 총유기탄소함량과 퇴적물 밝기($L^{\ast}$), 석영 함량, 오팔A 함량을 대비하여 밝혔다. 총유기탄소함량은 퇴적물 밝기와 높은 상관계수를 가진다. 코어 시료의 석영 함량은 총유기탄소함량과 퇴적시기에 따른 상관관계의 차이를 보이는데, 이것은 퇴적기작 차이에 의한 것으로 해석된다. 그리고 오팔 A와 총유기탄소함량의 상관관계는 퇴적장소에 따라 차이를 갖는다. 동해 울릉분지 코어 시료는 총유기탄소함량과 퇴적물 밝기가 높은 상관계수를 갖는데, 이것은 초기속성작용의 영향이 크지 않았음을 지시하는 것이다. 후기 홀로세에서는 총유기탄소함량이 거의 일정한 구간에서도 오팔A 함량이 큰 차이가 나타나는데, 이것은 퇴적장소에 따라 고해양 생산력의 차이가 있었음을 지시하는 것이다.

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Preliminary Study for the Capim Kaolin Mine in Brazil (브라질 까핌 카올린 광상에 대한 예비 연구)

  • Kim, In-Joon;Lee, Jae-Ho
    • Economic and Environmental Geology
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    • v.41 no.5
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    • pp.587-595
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    • 2008
  • The geology of the Capim region in Brazil is composed of Ipixua Formation in Mesozoic-Tertiary(Miocene), sedimentary rocks in Miocene, Barreiras Formation(sedimentary rocks) in Pleistocene and sediments in Holocene. Kaolin deposit consists of Barreiras Formation(average depth in 120m) composed of sandstone, clay, fine sand of Miocene to Pliocene age. Kaolin of the high grade is white in color and its thickness averages 7m. The orebody formed by kaolinite was confirmed by XRD, is shape of hexagonal, SK is above 33 degree. It is class A also suit for producing a paper without filtration. According to the CPRM report, the reservation of kaolin ore is amounts of 566,819,164 tons.

Monitoring of Moisture Content and Sediment Fineness as Predictors of Shoal Breaching in an Estuary

  • Lee, Seulki;Park, Sungjae;Lee, Chang-Wook
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.36 no.1
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    • pp.25-32
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    • 2018
  • Namdae-cheon in Gangwon-do Province, Korea, is a valuable well-preserved lagoon. The estuary of Namdae-cheon Stream is closed because of the surrounding natural sand shoal. Thus, during the dry season, river water cannot easily flow to the ocean and therefore stagnates. River water congestion causes environmental deterioration of estuaries, often by eutrophication. In this study, we examined wall disintegration in the estuary area and used it to determine appropriate measures for the conservation of estuary water quality in the future. A total of 24 sites were selected, with 13 sites on the west side and 11 sites on the east side of the estuary study area. Samples were collected and analyzed for particle size and moisture content both vertically and horizontally. Sedimentary deposition rate was measured, and subsidence analysis was performed. Particle size, water content, sedimentary deposition, and subsidence analyses indicated that flow shifted to the west during the study period. In conjunction with other variables that may affect changes in flow, these parameters can be used in future research to predict shoal breaches and associated changes in water flow direction.

Characteristic Nature of the Unconformity between Holocene and Late Pleistocene in the Tidal Deposits along the Western Coast of Korea

  • Park, Yong-Ahn
    • The Korean Journal of Quaternary Research
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    • v.17 no.2
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    • pp.13-14
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    • 2003
  • It is generally well known that Quaternary is characteristic geologically in terms of glacial and interglacial repeats and their associated unconformity formation. This paper deals with the first finding of the characteristic and significant meaningful unconformity between Holocene and late Pleistocene, which implies submergence and emergence of the tidal sedimentary basin along the western coastal zone of Korea during interglacial stage(IOS-5e) and glacial time(IOS-2). The stratigraphy of intertidal deposits in the Haenam Bay, western coast of Korea shows two depositional sequence units (Unit I of Holocene and Unit II of late Pleistocene) bounded by an erosional surface of disconformity. The disconformity is related to the latest Pleistocene sea-level lowstands (probably during the LGM). The Unit II is interpreted as intertidal deposit showing tidal sedimentary structures and crab burrow ichnology and has two parts (the upper part and the lower part) showing different lithology and character. The upper part of Unit II shows characteristic subaerial exposure features (emergence) and its related lithology. Such subaerially exposed upper part (more or less 4m to 5m in thickness) is characterized by yellow-brownish sediment color, cryoturbat-ed structure, crab burrow ichnofacies and high value of shear strength. Geochemical and clay mineral analyses of the upper part sediments also indicate subaerial exposure and weathering. In particular, very high value of magnetic susceptibility of the upper part in comparison to that of the lower part is interpreted as pedogenetic weathering during the subaerial exposure period.

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Geophysical and Sedimentological Characteristics of Lomilik Seamount, West Pacific (서태평양 Lomilik 해저산 퇴적환경 특성)

  • Lee, Hyun-Bok;Oh, Jae-Kyung;Park, Cheong-Kee;Chi, Sang-Bum;Kim, Jong-Uk;Moon, Jai-Woon;Nam, Sang-Heon
    • Ocean and Polar Research
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    • v.26 no.2
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    • pp.207-218
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    • 2004
  • Lomilik Seamount in the west Pacific was seismically surveyed and photographed to illuminate the bottom topography, the condition of manganese crust, and the characteristics of sedimentary environment. Lomilik Seamount has a NW-SE elongated bottom topography with steep slopes in the NESW direction part. Even though the steep slopes of the seamount are devoid of deposits, the summit area and gentle slope of the seamount are covered with thick deposits. The seismic data indicate that Lomilik Seamount is a flat-topped and step-faulted guyot of volcanic origin. Deep-sea camera photographs show that much of the seafloor is rippled in symmetrical and asymmetrical patterns. The traces of biological activity were distinct on gentle seafloor suggesting the low-energy bottom conditions. Some photographs also show outcrops encrusted with manganese crusts. Sedimentary environments in the Lomilik Seamount appear have been governed by regional morphology and strong bottom current.

Geoengineering Characteristics of the Cretaceous Rock Cut Slopes in Jinju area (진주지역 중생대 암반절토사면 지반특성)

  • Kim, Seung-Hyun;Lee, Jung-Yup;Rhee, Jong-Hyun;Koo, Ho-Bon
    • Proceedings of the Korean Geotechical Society Conference
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    • 2006.03a
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    • pp.652-661
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    • 2006
  • The cut slopes in Jinju area constitute the Cretaceous Sedimentary rock which is one of the most poor ground conditions. The geological rocks of the cut slopes are correlated with Jinju Formation. Most of the rocks consist of Black Shale layer, but the lower parts consist of Alkorsic White Sandstone. So, It is characteristic of the differential weathering due to the difference of rock species. Moreover, vertical joints which concentrate on the released rock and weak rock fragments are accompanied with minor faults. We make out face mapping about each slopes through the detailed field-study and deduce RMR and SMR from the field data. The strength properties of rocks were obtained from references, indoor tests, and Back Analysis method. And, choosing properties were used in the stability analysis as stereographic projection and limit equilibrium analysis and we establish the countermeasures for the cut slopes.

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