• The Korean Journal of Malacology
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• v.29 no.4
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• pp.291-301
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• 2013

This study researched and compared the sedimentation environment and photosynthetic pigments at Gomso (GS) -bay, Yoja (YJ) -bay and KangJin (KJ) -bay in May, 2012. It was shown that KJ-bay consist of C (clay) and M (mud), and GS-bay consists of Zs (silty sand) and Sz (sandy silt). Averagely, IL of YJ-bay was 4.98%, KJ-bay 6.10%, and GS-bay 1.45%. As for COD concentration, there were no places that exceeded Japanese sediment contamination standard 20 mg/g-dry. As for AVS concentration, in case of KJ-bay, two places exceeded Japanese sediment contamination standard 0.2 mg/g-dry. If we look into the average C/N ratio of bays, YJ-bay showed 8.50, KJ-bay 6.60, and GS-bay 5.52, thus all of them showed the characteristic of oceanic origin. As for the plankton make-up classified by photosynthetic pigments, diatom was dominant, and both ratios of pigment and C/chlorophyll. a showed the relatively lower distribution at GS-bay than at KJ-bay and YJ-bay. It is judged that this is related to the characteristic of flow-in, and it implies that predation process and decomposition by organic matters actively occurs at YJ-bay and KJ-bay.

• Ocean and Polar Research
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• v.24 no.4
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• pp.331-343
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• 2002

The southern tidal flat of Kanghwa Island with an area of approximately $90km^2$ is one of the biggest flats on the west coast of Korea. Surface sediments for sedimentary analyses were sampled at 83 stations in August 1997, September 1999 and August 2000. The very poorly-sorted mud sediments were predominant in the eastern part of the tidal flat, whereas the poorly-sorted sand-mud mixed sediments were dominant in the western part. The area of muddy sediment distribution diminished, but that of sandy mud sediment extended to southeastward tidal flat for three years. In the western part of tidal flat, deposition occurred during the period of spring to summer, whereas erosion occurred in winter. Sediment accumulation rates during three years indicated that the sediments deposited continuously in the eastern part of tidal flat, whereas eroded in the western part of tidal flat. Recently, construction of artificial structures such as new airport, island-connecting bridges and dikes near the tidal flat might change tidal current and river flow pattern. In order to reduce the ecological damage and to preserve tidal-flat environment, it is necessary to Investigate long-term impacts on sedimentary environment and ecology.

• Journal of the korean society of oceanography
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• v.35 no.1
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• pp.1-10
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• 2000

A two-dimensional numerical model was applied to investigate the sediment transport and sand bank formation in a macrotidal sea, the Kyunggi and Asan Bays. The tidal residual currents show quite complex pattern including counter-rotating eddies off the northwestern corner of the Dugjeok Island that reflect the promontory effect. Complex residual eddies are also present off the coast of the Taeanbando and in the Asan Bay. Net sediment transport pattern shows that sandy sediments in the Kyunggi and Asan Bays are generally transported landward from the outer sea suggesting sediment trapping inside the bays. This phenomenon may be related to the formation and maintenance of numerous sand banks in this macrotidal sea. Alternate occurrences of deposition and erosion predicted from the numerical model along the coast of the Taeanbando with strong deposition on the southwestern part of the 'Jangansatoe'(JSB), a large sand ridge off the coast of the Taeanbando appear to reflect the loose connection of JSB, The 'Joongangcheontoe', a central sand bank (CSB) with the main axis in the NW-SE direction in the Asan Bay may undergo a modification with strong deposition along the northeastern flank. These results indicate that the sand banks are actively modified and maintained by the strong tidal currents in this shallow macrotidal sea.

• Journal of Environmental Impact Assessment
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• v.12 no.1
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• pp.9-22
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• 2003

To consider environmental characteristics in the scope of geochemistry of streams, Hwasun area, soil, sediment and water samples near/in the streams were analyzed in texture and metal contents of soil and sediment and in quality in water. From those analyses, the soils are loamy sand, sandy loam, loam and silty loam in texture. And, the sediments are slightly gravelly sand, gravelly sand and gravelly muddy sand in facies. Metal contents in soils and sediments are of high near Hwasuneup and Hwasun coalfield. In peculiar, P, Co, Li, Ni, Zn and Pb exceed over crust mean contents. Physico-chemistry of above streams according to pH-Eh and Piper's diagrams indicates that the streams are, typically, assigned to natural river water. Water qualities of BOD, T-N and T-P in areas near Hwasun coalfield, Dongmyeon and Hwasuneup are polluted over V level. Enrichment factor(EF) representing metal condensation in P, Cu, Zn and Pb appear near Hwasun coalfield and Hwasuneup from the soil and sediment samples, in part. Additionally, river water in dry season is very high in BOD, T-N, $Na^+$ and ${SO_4}^{2-}$. It is suggested that the relatively high metal contents in the stream be connected with above coalfield and urban areas.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.5
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• pp.289-302
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• 1991

Laboratory determination of acoustic property for unconsolidated sediment of Kwangyang Bay was carried out. The compressional wave velocity was correlated to other physical properties and sediment textures to establish a geoacoustic model of the bay. The model was compared to the North Pacific continental terrace sediment. Velocity of the bay is systematically lower(0.02-0.04km/s) than that of the North Pacific. Average velocity of the bay is 1.521km/s. The lowest velocity is measured at the southwestern part of the bay. This area coincides with high amount of fine-grained sediment related to slower circulation. The overall tendency is, however, similar to the North Pacific continental terrace sediment.

• Journal of Soil and Groundwater Environment
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• v.8 no.1
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• pp.81-86
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• 2003

Understanding the penetration behavior of the spilled oil is very important to remove itself and to minimize its impact on intertidal biological communities by earlier treatment of the oil. The purpose of this study is to clarify the effects of wave and tidal actions on the penetration of spilled oil and to evaluate main factors of oil penetration using a sandy-beach model. Infiltration processes into the sediments showed significant difference between seawater and crude oil. Seawater was infiltrated by both wave action and tidal fluctuation into the sediments in sandy beach. However, spilled crude oil penetrated into the sediments only by falling tides and not by wave action, and the first tide is most important for the penetration of stranded oil. Over 70% of bulk fraction in penetrated crude oil was concentrated to the top 2 cm sediment-layer when spilled oil volume was 1 L/$\textrm{m}^2$. Moreover, the penetration of stranded oil into the sandy beach sediments was strongly correlated with the oil viscosity affected by temperature.

• Journal of The Geomorphological Association of Korea
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• v.25 no.1
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• pp.1-17
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• 2018

The characteristics and burial ages of sand sediments on the Jiduri coast in Daechung-myeon, Ongjin-gun, Incheon were investigated. Daecheong Island is the area where the characteristics of the rocky coast and sand coast are shown. Various studies have been conducted on the Okjukdong sand dune that appears in the north of the island. However, there has been no study on the sandy sedimentary topography of the Jiduri and Moraewul area in the south. The sandy sedimentary terrain of Jiduri is divided into sandy beaches, sand dunes and sand deposits along the slope including climbing dune. Overall, the depth of sandy sediments in Jiduri is not deep. The characteristics of sandy sediments and burial ages were investigated at an elevation of about 23 m above sea level at the back of Jiduli Beach and 46 m above sea level at the ridge line between Jiduri and Moraewol. From the Jiduri coast to the hillside behind, the average grain size decreases and the sorting becomes better as it moves from the intertidal zone to the beach and the foredune. This indicates the selective sand transport by the wind and can be judged by the terrain formed under the current sedimentation environment. The average grain size at the upper part of the section of JD-1 (elevation of about 23m MSL) was $1.6918{\varphi}$ of medium sand. The sorting was $0.4584{\varphi}$, skewness was -1.0491 and kurtosis was -1.2411, respectively. Particularly, the average particle size of the crosssection issomewhat uniform, but the color of the constituent material changes from brown to black. In the case of JD-2 (about 46 m MSL), the mean grain size of the section was $1.7943{\varphi}$, the sorting was 0.4931, the skewness was -1.1163, and the kurtosis was 1.2133. On the other hand, the brown and black layers of JD-1 exhibited a burial age of $0.1{\pm}0.0ka$ and the JD-2 had a burial age of $0.7{\pm}0.0ka$.

• The Korean Journal of Quaternary Research
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• v.13 no.1
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• pp.99-106
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• 1999

The surfacial bottom sediments on the nearshore to infer continental shelf off the Taean Peninsular, west coast of Korea are dominantly medium-grained clastic sands. About 60% and 20% of these clastic sands are partly iron-stained quartz and completely iron-stained quartz, respectively. Characteristically glauconite grains are abundantly found in these clastic sands. The mineral compositions of clastic sandy sediments in the study area are very similar to those of East China continental shelf sediments. Accordingly, such iron-stained quartz grains, glauconite grains and associated textural characteristics seem to indicate that those sandy sediments are relict sediments related to past condition, i.e. Quaternary low stands of sea level.

• The Korean Journal of Malacology
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• v.21 no.1
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• pp.65-70
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• 2005

The purpose of this study is to determine the appropriate substrate for larval settlement and spat growth in the purple clam, Saxidomus purpuratus in laboratory culture. Larvae were reared with 3 different types of sediments (mud, sand, and mixed) for 46 days in settlement experiment, and settled spats were further grown in 3 types of sediments for 36 weeks in growth experiment. The density of settled spats in muddy sediments was more than 2 times higher than those in mixed or sandy sediments. But, the average size of settled spats in muddy sediments was smaller than those in mixed or sandy sediments. After 36 weeks of growth period, growth rate decreased as shell length increased. When shell length was less than 2 mm, growth rate in mixed sediments was significantly higher than that in sandy sediments. When shell length was more than 2 mm, there was no significant difference in growth rate among different substrates. Sediment type affected growth rate only when the spats were relatively small (less than 2 mm). Muddy sediments seems better for larval settlement, while mixed sediments is best for spat growth. We suggest the laboratory procedure for enhancing seedling production of S. purpuratus.

• Journal of the Korean earth science society
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• v.44 no.4
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• pp.264-274
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• 2023

The Korea Strait comprises a continental shelf in a shallow sea that experienced glacio-eustastic sea-level changes during the Quaternary period. A long core of 76.6 m in length was acquired at the South Sea Drilling Project site (SSDP-101; 34°19.666'E and 128°16.335'N) with a 60 m water deep. The uppermost massive sand beds were interpreted as sandy sediments of the nearshore marine sand ridge in the shallow sea during the transgression of sea level, whereas the lower parts of alternating sandy and muddy beds were interpreted as deposits in marsh, estuary, and tidal flat environments. A three-layered geoacoustic model was reconstructed for the sedimentary succession in the high-resolution seismic profile based on a 140-grain size and sediment type of core SSDP-101. For the actual underwater simulation and experiments, the in-situ P-wave speeds were calculated using the sound speed ratio of the Hamilton method.