• Journal of Wetlands Research
• /
• v.15 no.4
• /
• pp.493-500
• /
• 2013

Comparisons of surface sediment distributions in summer 1997 and 2011 and elevations on the tidal flats in April 1998 and March 2013 had been used for understanding the long-term changes of sedimentary environments at southern Kanghwa tidal flat, west coast of Korea. The mud sediments dominated in the eastern part and sandy mud sediments dominated in the western part of the tidal flat in 1997. In 2011, the surface sediments were dominant mud and sandy mud at Sunduri and Tonggum in the eastern part, sandy mud at Tongmakri in the middle part, and sand and muddy sand at Yeochari and Changhwari tidal flats in the western part. The area of mud sediments had decreased, but that of sand-mud mixed sediments extended to eastward tidal flat for 14 years. The long-term topographic changes showed that deposition occurred at Tongmakri and Yeochari and erosion occurred at Changhwari tidal flat during 15 years. These changes should be effected the local hydrodynamic changes by several constructions near the tidal flat since the 1990s.

• Economic and Environmental Geology
• /
• v.36 no.3
• /
• pp.149-157
• /
• 2003

Deep sea core samples were taken in the southwestern part of the Ulleung Basin in order to characterize the properties of shallow gases in the sediment. Amount of shallow gases in the sediments were calculated by head space techniques, and chemical and isotopic compositions of hydrocarbon gases were analyzed. Geochemical analyses were carried out on the gas bearing sediments to find out relationship between natural gas contents and organic characteristics of the sediments. Seismic characteristics of shallow gases in the sediments were also examined in this study. The amount of the hydrocarbon gases in the sediments range from 0.01% to 11.25%. Calculation of volume of gas per volume of wet sediment varies from 0.1 to 82.0 ml HC/L wet sediment. Methane consists 98% of the total hydrocarbon gases except for two samples. Based on the methane content and isotopic composition$(\delta^{13}c)$: -94.31$\textperthousand$~-55.5$\textperthousand$), the hydrocarbon gases from the sediments are generated from bacterial activities of methanogenic microbes. Contents of hydrocarbon gases are variable from site to site. Volume of shallow gases in the sediments shows no apparent trends vs. either characteristics of organic matter or particle sizes of the sediments. Gas concentration is high in the area of seismic anomalies such as blanking zone or chimney structures in the section. Physicochemically the pore water and the formation water systems are saturated with gases in these areas. Concentration of hydrocarbon gases in the sediments in these area shows favorable condition for generation of gas hydrate, as far as the other conditions are satisfied.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2001.09a
• /
• pp.212-215
• /
• 2001

남악지역에 분포하는 조간대 퇴적층의 층서구조와 퇴적심도 및 기반암의 단열구조를 파악하기 위한 전기비저항탐사를 실시하였다. 조간대 퇴적물에서 비저항은 하부로 갈수록 증가하며 대부분 3.0 Ohm-m이하의 비저항으로 고비저항의 기반암의 기반암과 뚜렷한 경계를 보여준다. 퇴적층의 층후는 퇴적지 중앙부에서 30m를 최대로 북쪽 (고해안선)과 남쪽 (영산강)으로 갈수록 감소하는 경향을 보여주는데 선행 조사된 시추결과와 일치한다. 일부 지역의 전기비저항 해석단면과 시추단면에서 견고한 점토질 (stiff)의 지층이 분포하는데 이 지층은 북서-남동 방향의 고해안선과 나란하게 분포한다. 이것은 퇴적물을 공급한 흐름의 방향과 조간대의 확장방향이 북서-남동 방향임을 지시한다. 기반암의 단열구조로 판단되는 저비저항대는 조사지역의 동부에 집중되어 있으며 단열대의 연장방향은 북서-남동 방향이 우세하다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2006.04a
• /
• pp.415-418
• /
• 2006

회동저수지를 중심으로 수영강 일대 하상퇴적물에 대한 PAHs(Polycyclic Aromatic Hydrocarbons) 오염특성 연구가 진행되었다. 하상퇴적물의 화학분석결과, 16 EPA PAHs 중 naphthalene 등 총 15개 성분이 검출되었으며, benzo(a)anthracene과 chrysene의 검출빈도가 가장 높고, 총 PAHs는 최대 7,116 ppb가 검출되었다. 한편 퇴적물 내 PAHs의 심도별 함량 변화는, 대체로 하부 시료에 비해 상부 시료에 PAHs 함량이 높게 나타나며, 특히 상부의 점토질 토양과 하부의 현지 토양이 함께 산출되는 시료의 경우, 하부 현지 토양에서의 PAHs 함량에 비해 상부 점토질 토양에서의 PAHs 함량이 높으며, 이는 PAHs가 수영강 으로부터 유입되어 주로 상부 점토질 퇴적물에 축적된 결과로 판단된다. PAHs의 기원은 전반적으로 수영강 상류지역에서는 연소 기원을 보이며, 수영강 하류에서는 교량 및 도심지역에서의 차량통행과 관련이 있는 석유류의 특징을 나타내며, 회동저수지의 경우 석유류와 연소 기원의 특징을 복합적으로 보여주고 있다.

• 한국신재생에너지학회:학술대회논문집
• /
• 2008.10a
• /
• pp.200-202
• /
• 2008

동해 울릉분지에서는 시추선 RemEtive를 사용하여 UBGH-X-01 가스하이드레이트 탐사가 2007년에 실시되었다. 본 연구에서는 천부 가스하이드레이트가 확인된 UBGH1-10 정점에서 무인잠수정(Quantam WROV)을 사용하여 획득된 푸쉬코어와 해저지형 분석을 수행되었다.UBGH1-10 정점은 seismic chimneys의 탄성파 특성이 발달된 지역이다. 이곳에서는 해저표면으로부터 수 m 하부에서 가스하이드레이트가 발견되었다. 이 정점은 수 m 높이의 얕은 둔덕들이 무인잠수정에 부착된 비디오 카메라에 의해서 관찰되었다.이곳에서 채취된 길이 약40 cm의 푸쉬코어는 생물교란된 뻘질 퇴적물로 구성되어 있으며, 가스하이드레이트와 chemosynthetic community는 관찰되지 않았다. 푸쉬코어는 X-ray fluorescence scanner를 사용하여 퇴적물의 26가지 원소 조성을 분석하였다. UBGH1-10 정점의 산화환원환경은 Mo/Al과 Mn/Ti 원소비를 이용하여 천부 가스하이드레이트가 발견되지 않은 UBGH1-9와 UBGH1-1 정점과 대비하였다. 이 정점의 일차생산력은 Ba/Al 원소비를 이용하여 다른 정점과 대비하였다. 천부 가스하이드레이트가 발견된 UBGH1-10 정점은 활발한 가스방출과 관련된 생물집단 서식 또는 자생광물 형성의 흔적이 발견되지 않으며, 퇴적물에서도 산화환원환경과 일차생산력의 큰 차이가 관찰되지 않는다.

• Journal of the Mineralogical Society of Korea
• /
• v.16 no.2
• /
• pp.151-159
• /
• 2003

$^{31}$ /P NMR and XRD have been used to study the mineralogical compositions and the phosphorus species in marine sediments near Wolsung nuclear power plant. The core samples with 30cm depth were investigated and no mineralogical changes have been found. The studied marine sediments were composed of quartz, albite, microcline, calcite, and some clay minerals such as illite, smectite, chlorite, and kaolinite. Only orthophosphate-monoester and very small amount of ortho-phosphate-diester were identified as phosphorus species in the studied sample, different from the species reported in other countries. These phosphorus species are mainly from organisms and was exposed to the oxic conditions. The consistent mineralogical compositions as well as the same phosphorus species throughout the entire core samples indicate that the constant oxic condition was kept without any changes in sedimentary conditions or the sediments were deposited with different sedimentary conditions, but later they were disturbed by other activities and exposed to the surface oxic conditions continuously.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.27 no.2
• /
• pp.200-214
• /
• 1994

In order to clarify the benthic environmental properties as a part of a study on the macrobenthic community in the Chinhae Bay System, water temperature, salinity and dissolved oxygen (DO) in surface and bottom water layers, mean grain size (${\phi}$) and sediment organic carborn (SOC) in surface sediment were analyzed at twelve stations during the period from June 1987 to May 1990. A high sediment organic carbon and hypoxic condition in bottom water due to the development of summer stratification and fine sediment texture toward the inner bay were important environmental characteristics of Chinhae Bay. Hypoxic conditions began to develop in the inner bay from May, and gradually spread toward the outer bay in summer with a peak in September when half the bay was affected by this oxygen deficiency. Recovery from this hypoxic condition in the bottom layer was observed from the beginning of autumn together with a disappearance of the summer stratification. Principal component analyses were carried out from the following five environmental variables:mean water temperature, salinity, dissolved oxygen in the bottom layer and mean grain size, sediment organic carbon in surface sediment. The twelve stations were classified into four areal groups based on the analyses. The division of the areal groups had high correlations to the sediment organic carbon content.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.10 no.1
• /
• pp.1-12
• /
• 2007

Mooring survey for measurement of tidal current and suspended sediments was carried out at 4 inlets of Yeoja Bay in April, 2000 in order to understand the source of sediment supply. Net suspended sediment transport load during 2 tidal cycles through the M-1(West Inlet) was $133.88\;kg{\cdot}m^{-1}$ toward the Yeoja Bay, whereas the flux through the M-2(Jabal Inlet) was outward the Bay with the amount of $146.43\;kg{\cdot}m^{-1}$. The influx through the M-3 and 4(Bulgyo and Dong Isa Stream) was $23.25\;kg{\cdot}m^{-1}$ and $4,312.31\;kg{\cdot}m^{-1}$ toward the Yeoja Bay, respectively. Influx of suspended sediment on Yeoja Bay mainly occurred in the Dong Isa Stream. In the wet season the composition of surface was coarser-grained than dry season, possibly due to the influx of silty sediment from Dong Isa Stream In the wet season.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2004.09a
• /
• pp.248-251
• /
• 2004

일반적으로 유기오염 물질의 경우 sequestration 또는 aging 현상에 의해 탈착저항성을 띠게 되는 것으로 알려져 있다. 그러나 중금속의 경우 흡/탈착반응은 탈착저항성이 없는 가역적 반응이라는 보고가 있는 반면 홉/탈착 반응은 비가역적이며 탈착저항성이 존재한다는 보고도 있다. 본 연구에서는 해양 연안 퇴적물에 대한 납의 흡/탈착 실험을 통하여 탈착 저항성을 화인하고 연속추출 실험을 수행함으로써 탈착 저항성 부분의 크기를 규명하고자 하였다. 그리고 각기 다른 pH(4, 6)에서 흡착 실험을 수행함으로써 pH에 따른 흡착친화도를 규명하였다. 그 결과 퇴적물에 대한 납의 흡착량은 높은 pH(6)에서 더 많았고, 각 pH 범위에서 납은 탈착저항성을 가지는 것으로 나타났으며, 연속추출결과 Organic Material bound부분에 66% 정도가 흡착되어 있음을 알 수 있었다.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.4 no.4
• /
• pp.338-348
• /
• 1999

Physical properties of mudbelt sediments in the southeastern inner shelf of Korea are studied from 14 cores. Physical properties, compressional wave velocity, and sediment texture for core sediments are analyzed. The major source of sediment in the study area is the Nakdong River. Fine-grained sediments from the river are transported northeastward by coastal circulation and the Tsushima Current, resulting in a gradual northeastward increase in porosity and a decrease in wet bulk density and velocity. The trend matches well with the bathymetry. The mean grain size appears to be the most important variable to determine the physical properties and velocity. The variations of physical properties with burial depth are dependent more strongly on sediment texture than compaction and/or consolidation. Correlations between the physical properties and the sediment texture show slight deviations from those of the continental terrace sediment in the North Pacific and inner shelf sediment in the South Sea of Korea. The velocity is higher than that of the North Pacific and the South Sea sediments between these areas. This is probably due to differences in sedimentary, environment and mineral compositions. The higher sediment velocity in the study area may also be attributed to the escape of gas from pore space which decreases void ratio.