• Journal of the Korean earth science society
• /
• v.25 no.1
• /
• 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.

• Journal of Environmental Science International
• /
• v.25 no.10
• /
• pp.1433-1444
• /
• 2016

South Korea is a maritime nation, surrounded by water on three sides; hence, it is important to preserve in a sustainable manner. Most areas, especially those bordering the East Sea, have been suffering from severe coastal erosion. Information on the sediment yield of a river basin is an important requirement for water resources development and management. In Korea, data on suspended sediment yield are limited owing to a lack of logistic support for systematic sediment sampling activities. This paper presents an integrated approach to estimate the sediment yield for ungauged coastal basins by using a soil erosion model and a sediment delivery rate model in a geographic information system (GIS)-based platform. For applying the sediment yield model, a basin specific parameter was validated on the basis of field data, that, ranging from 0.6 to 1.2 for the 19 gauging stations. The calculated specific sediment yield ranged from 17 to $181t/km^2.yr$ in the various basin sizes of Korea. We obtained reasonable sediment yield values when comparing the measured data trends around the world with those in Korean basins.

• Ocean and Polar Research
• /
• v.21 no.2
• /
• pp.127-136
• /
• 1999

Radiolarian assemblages from KODOS area were analyzed in order to understand the biostratigraphy and paleoceanography of deep-sea sediment from the Northeast Equatorial Pacific. The sediment core was divided into two or three units on the basis of the chemical and physical properties. In the upper sediment, mixtures of Quaternary and Tertiary radiolarians are found indicating active reworking processes. Dissolution of radiolarians seem to increase with depth. Radiolarians are seldom in Unit III presumably due to dissolution and corrosion. The middle part of unit I appears to correspond to Collosphaera invaginata Zone (0.21 Ma). Unit II belongs to Collosphaera tuberosa Zone. Based on the absence of Stylatractus universus, we estimate its age to be younger than 0.42 Ma. Based on our analyses of radiolarians in Unit I and II, we estimated the age of unit III as Tertiary, particularly from Oligocene to Miocene. There may to be hiatuses of more than 3 My from late Miocene to Pliocene, which probably resulted from erosion and dissolution by the Antarctic Bottom Water Sedimentation rates during Quaternary range from 0.15 to 0.50 mm/ky with significant variabilities among stations. Radiolarians in the study area were mostly warm-water species.

• KCID journal
• /
• v.8 no.2
• /
• pp.64-72
• /
• 2001

Sihwa dyke was constructed during the period from June, 1987 to January, 1994 and the sluice gates were opened to allow sea water intrusion and outflow to improve water quality of the lake since June, 1997. Bottom sediment samples from 29 stations were co

• Proceedings of the Korea Society of Environmental Toocicology Conference
• /
• 2004.11a
• /
• pp.48-48
• /
• 2004

• Journal of the korean society of oceanography
• /
• v.34 no.4
• /
• pp.207-213
• /
• 1999

Sediment physical properties (compressional wave velocity, grain density, dry bulk density, and wet bulk density) are correlated to the paleoenvironmental parameters (coarse fraction, oxygen isotope, and planktonic foraminifera fragmentation) to reveal the possible interrelationship in the latest Quaternary sediments of the Ulleung Basin, the East Sea of Korea. Laboratory determinations of physical properties and paleoenvironmental parameters have been conducted on four piston core sediments. There are slight differences in the physical properties between glacial and interglacial period sediment sections. This is due to the large fraction of coarse grains of volcanic and terrigenous sediments relative to carbonate sediments. However, dry bulk density as an indicator of carbonate abundance in pelagic environment shows higher values at the lower part of cores, reflecting deeper CCD in the glacial period. Changes in velocity also relatively parallel to those in sediment coarse fraction, number of planktonic foraminifera, and wet bulk density. Therefore, we suggest that high-resolution physical properties may be used as a valuable tool for paleoenvironmental interpretation in the Ulleung Basin.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.3 no.4
• /
• pp.83-93
• /
• 1983

A non-linear numerical tidal model of the Yellow Sea and the East China Sea is used to derive the mean and maximum bed stress the mean and maximum transport potential on the continental shelf. It has provided a preliminary assessment of relation between sediment transport paths and the mean and maximum bed stress distribution determined from the numerical model.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.19 no.4
• /
• pp.247-258
• /
• 2016

Physical and acoustic properties of sediment on the southwestern Taean Penisula, the Yellow Sea, were studied using eight piston cores. The sediments in the study area are largely composed of sand which has been deposited with sea-level change after LGM(Last Glacial Maximum). After the sea-level rise, fine-grained sediments discharged from Keum River and neighboring coast area were deposited as muddy sand or sandy mud. Results of these sedimentary environment in this area, the texture of sediments are different from place to place with variable horizontal and vertical distribution of physical and acoustic properties. Correlations among the physical, geoacoustic properties, and mean grain size show slight deviations from those of the South Sea in spite of similar pattern. This is probably due to the differences in sedimentary environment, mineral composition, and measurement system.

• Ocean and Polar Research
• /
• v.28 no.3
• /
• pp.317-329
• /
• 2006

To assess the contamination status of organochlorine pesticides in the marine environment of Saemangeum, surface seawater and sediments were collected and analyzed. Organochlorine pesticides were widely distributed in the Saemangeum environment, with DDT, HCH and endosulfan II contamination being particularly prevalent. The overall concentrations of DDTs, HCHs, and endosulfan II in surface seawater were in the rage of 0.03-0.65ng/l (mean value: 0.36ng/l), 1.31-4.54ng/l (2.63 ng/l), and not detected (ND)-0.96ng/l (0.49ng/l), respectively. Among the target organochlorine pesticides, endosulfan II showed the hi띤est level at the river mouth flowing into the Saemangeum. Additionally, its negative gradient from the rivers to the outside and a good correlation with $NO_3^-$ indicate that endosulfan ll inflows to the Saemangeum through the river; this conclusion is also supported by the elevated levels of endosulfan II in sediments at the river mouth. In sediment, the concentration of DDTs, HCHs, CHLs, and endosulfan II were in the range of 0.05-1.96 ng/g, 0.03-0.31ng/g, 0.01-0.13ng/g, and ND-0.62ng/g, respectively. Levels of contamination in Saemangeum are relatively lower than the median concentrations previously observed at the Korean coastal regions and sediment quality guidelines suggested by NOAA (Long et at. 1995).

• Journal of Navigation and Port Research
• /
• v.29 no.6 s.102
• /
• pp.589-593
• /
• 2005

A laboratory study on the adsorption of nitrate in polluted coastal water using various materials including several types of dredged sediments(ST) and yellow c1ays(YC), which are activated by heat(HT), bioleaching for heavy metal removal(BL) and neutralization(NR) was performed. The equilibrium time of the adsorption for the sediment bioleached and treated by heat(BL-HT-ST) was only 17min which was faster than the sediment bioleached, neutralized and treated by heat(BL-NR-HT-S) (25min) or the sediment treated by the bioleaching process(BL -ST)(27min), but longer equilibrium times for yellow c1ay(YC) or heat treated yellow day(HT- YC) were required. The adsorption processes of nitrate in sea water for tested material could be described by Freundlich isotherm, but were significantly affected by surface characteristics of the materials. The adsorption capacities for raw sediment and heat treated sediment were 2.12 and 2.19mg NO3-N/g, respectively, which were higher than others, indicating that the sediment activated by heat could be used as a material for the improvement of nearshore water quality.