• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.2
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• pp.206-218
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• 2020

Located mostly inside the megacity of Busan, the Busan Southern Port is a multifunctional port with various nearby industry activities, including a joint fish market, ship repair facilities, and fishing boat facilities. If toxic chemicals generated by the industrial activities continue to flow into and accumulate in the sediment of the port, they can affect aquatic ecosystems and humans. Therefore, in this study, distribution levels and potential influent sources of organic pollutants, including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and butyltin compounds (BTs), in the sediment were investigated. The sediment samples were collected from eight sampling sites in November 2013 (first phase) and November 2014 (second phase). The mean concentrations of PAHs, PCBs, and BTs in the first and second sampling phages were 4174.0 ng/g-dry wt. and 1919.0 ng/g-dry wt., 166.3 ng/g-dry wt. and 21 ng/g-dry wt., and 50.9 ng/g-dry wt. and 30.8 ng/g-dry wt., respectively. The concentrations of the organic pollutants detected in the seabed sediments were lower in the second phase than in the first phase. In this study, the inflow sources of PAHs, PCBs, and BTs were found to be combustion, land, and municipal sewage or industrial wastewater, respectively.

• Journal of the Korean Geophysical Society
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• v.2 no.3
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• pp.191-200
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• 1999

Analysis of chirp high-resolution seismic profiles from the central Yellow Sea reveals that depositional environments in this area can be divided into three distinctive zones from west to east: (1) subaqueous delta system near the Shandong Peninsula, (2) erosional zone in the central Yellow Sea, and (3) tidal sand ridges and sand waves near the Korean Peninsula. The Shandong subaqueous delta, extending southward from the Shandong Peninsula, changes gradually into prodelta southeastward. The sediments originated from the Yellow River are transported southward along the Chinese coastal area. The erosional zone in the central Yellow Sea contains numerous paleochannels and shows linear erosional features trending northwest-southeast. The erosional zone would be dominated by non-depositional or erosional processes during the Holocene. Tidal sand ridges and sand waves are well developed along the western coast of Korea. The residual sands, which were originally fluvial sediments at the sea-level lowstand, are interpreted as the result of winnowing process during the sea-level rise. Modern sand ridges generally migrates in a northeast-southwestern direction, which coincide with dominant tidal current direction.

• Geophysics and Geophysical Exploration
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• v.16 no.3
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• pp.145-153
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• 2013

High-resolution chirp profiles were analyzed to investigate the echo types of near-surface sediments in the Yellow Sea off the Baegryeong Island. On the basis of seafloor morphology and subbottom echo characters, 7 echo types were identified. Flat seafloor with no internal reflectors or moderately to well-developed subbottom reflectors (echo type 1-1 and 1-2) is mainly distributed in the southern part of the study area. Flat seafloor with superposed wavy bedforms (echo type 1-3) is also distributed in the middle part. Mounded seafloor with either smooth surface or superposed bedforms (echo type 2-1, 2-2, and 2-3) occurs in the middle part of the study area. Irregular and eroded seafloor with no subbottom reflectors (echo type 3-1) is present in the northern part of the study area off the Baegryeong Island. According to the distribution pattern and sedimentary facies of echo types, depositional environments can be divided into three distinctive areas: (1) active erosional zone due to strong tidal currents in the northern part; (2) formation of tidal sand ridges in response to tidal currents associated with sea-level rise distributed in the middle part; and (3) transgressive sand sheets in the southern part. Such a depositional pattern, including 7 echo types, in this area reflects depositional process related to the sea-level rise and strong tidal currents during the Holocene transgression.

• Journal of the Korean earth science society
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• v.23 no.8
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• pp.722-735
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• 2002

In order to reveal sedimentary facies and geochemical characteristics on sediments distributed in upper intertidal zone, the southwestern coast of Korea, grain size and metal content analyses to the sediments were carried out. The grain size distribution of sediments shows very wide range from gravel to mud. The sediments are very well sorted to very poorly sorted and mostly positively skewed. Geochemical behavior of metals in the sediments is dependant on grain size, in part, but might be much controlled by complex submarine topography, highly varied tidal currents and surrounding land geology in the study area. Igeo (index of geoaccumulation) representing metal condensation in the sediments moderately/strongly polluted in Co and Cr and moderately polluted in Cu and Ni. But notable metal condensations are not found in the study area. So, it might be interpreted that grain size and metal content distribution tendencies in the sediments are considerably influenced by complex submarine topography, highly varied tidal currents and surrounding land geology.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.29 no.1
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• pp.14-27
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• 2024

Unlike the shelf sand ridges moribund in motion, nearshore sand ridges are highly mobile, sensitive to changes in ocean environments, thereby becoming of particular interest with respect to morphological changes. About 5 km off the Daesan port, the Jangan Sand Ridge has been undergoing severe subsea morphological change over the past two decades. Understanding the nature of sand ridges is critical to elucidate the causes of morphological changes. In this context, this study aims at understanding the characteristics and distribution patterns of surface sediments of the ridge and its vicinity. For this purpose, 227 sediment samples were acquired using a grab-sampler, the grain sizes being analysed by the sieve-pipette method. In addition, comparison of grain sizes in sediments between 1997 and 2021 was made in order to investigate the 25-years change in sediment composition. Surface sediments along the ridge axis are fine to medium sands with 2-3 phi in mean grain size, whereas, in the trough of ridge, the sediments are composed of gravels and muddy sandy gravels with mean sizes of -2 to -6 phi. Sediments in the crest of the ridge are well-sorted with normal distribution, on the other hand, the basal sediments are poorly-sorted and positively skewed. Along the ridge crest, the sediments are negatively skewed. From 1997 to 2021, the ridge sediments became largely coarser about 0.5 phi. Such coarsening trend in mean grain size can be explained either by elimination of fine sediments during high waves in winter or elimination of fines suspended during sand mining activities in the past. Spatial distribution pattern of surface sediments shows that ca. 30 m thick of the sand ridge itself overlies the thin relict gravels. The strong asymmetry of sand ridge, the exposure of ridge base, and reworked gravel lags suggest that Jangan sand ridge is probably sediment-deficit and hence erosive in nature at present.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.3
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• pp.273-281
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• 2002

Determination of sediment type is generally based on ground truthing. This method, however, provides information only for the limited sites. Recent developments of remote classification of seafloor sediments made it possible to obtain continuous profiles of sediment types. QTC View system, which is an acoustic instrument providing digital real-time seabed classification, was used to classify seafloor sediment types in the Suyoung Bay, Pusan. QTC View was connected to 50 kHz echo sounder, All parameters of QTC View and echo sounder are uniformly kept during survey. By ground truthing, the sediments are classified into seven types, such as slightly gravelly sand, slightly gravelly sandy mud, gravelly muddy sand, clayey sand, sandy mud, slightly gravelly muddy sand, and rocky bottom. By the first remote classification using QTC View, four sediment types are clearly identified, such as slightly gravelly sand, gravelly mud, slightly gravelly muddy sand, and rocky bottom. These are similar to the result of the second survey. Also the result of remote classification matches well with that of ground truthing, but for sediment type determined by minor component. Therefore, QTC View can effectively be used for remote classification of seafloor sediments.

• Economic and Environmental Geology
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• v.9 no.4
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• pp.213-223
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• 1976

Proceeding from general elementary principles to more specific abstract problems, we have attempted the rearrangement of the research results as they are known at present concerning the propagation and attennation of the elastic wave in submarine layers. We have derived the elementary equations of the elastic wave. In addition, the relationship of the propagation of the elastic waves in the sea water mass and the reflection of the waves from the water-sediment interface are treated and presented in different sections.

• 한국해양학회지
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• v.29 no.3
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• pp.278-286
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• 1994

Tidal sand ridges, which develop in Kyeonggi Bay generally parallel to the direction of tidal current on the sea bottom are also well shown in seismic profiles, surface and core samples were obtained from sand ridge field near the Palmi Do for the study of origin and sedimentary environments of these sand ridges. Sand ridge field near Palmi Do can be divided into 3 seismic units(unit A, B, C), and each unit has one sand ridge(ridge A, B, C), Ridge A that shows clinoform prograding southeastwards is generally parallel with tidal current trending northeast to southwest(40$^{\circ}$). It means that sand ridge is migrating to southward. Unit B includes a sand ridge and a channel fill structure in seismic profiles. Compared with ridge A, ridge B has similar direction, magnitude and internal reflectors. So ridge B developed in the similar sedimentary environments to ridge A about 10 m lower than present sea level. As the rise of sea level, channel fill structure formed as the deposit of fine sediments with the shape of conformable bedding or horizontal bedding.

• Proceedings of KOSOMES biannual meeting
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• 2017.04a
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• pp.218-218
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• 2017

• Journal of the Korean earth science society
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• v.41 no.6
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• pp.588-598
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• 2020

The seafloor geology of Ieodo, a submerged volcanic island, has been poorly understood, although this place has gained considerable attention for ocean and climate studies. The main purpose of the study is to understand and elucidate types, distribution patterns and provenance of the surficial sediments in and around the Ieodo area. For this purpose, 25 seafloor sediments were collected using a box-corer, these having been analyzed for grain sizes. XRD (X-ray Diffraction) analysis of fine-grained sediments was conducted for characterizing clay minerals. The peak of Ieodo exists in the northern region, while in the southern area, shore platforms occur. The extensive platform in the south results from severe erosion by strong waves. However, the northern peak still survived from differential weathering. Grain size analyses indicated that gravels and gravelly sands with skeletons and shells were distributed predominantly on the volcanic apron and shore platform. Muddy sediments were found along the Ieodo and the adjacent deeper seafloor. Based on the analysis of clay mineral composition, illites were the most abundant in fine muds, followed by chlorites and kaolinites. The ratio plots of clay minerals for the provenance discrimination suggested that the Ieodo muds were likely to be derived from the Yangtze River (Changjiang River). As a consequence, gravels and gravelly sands with bioclastics may be supplied from the Ieodo volcanic apron by erosion processes. Wave activities might play a major role in transportation and sedimentation. In contrast, fine muds were assumed to be derived from the inflow of the Yangtze River, particularly in summer. Deposition in the Ieodo area is, therefore, probably controlled by the inflow from the Changjiang Dilute Water and summer typhoons from the south.