• Journal of The Korean Society of Agricultural Engineers
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• v.53 no.6
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• pp.43-50
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• 2011

The fractal method has recently been applied to a model for determining soil grain size distribution. The objective of this study is to review the applicability of the fractal method for a analysis of submarine sedimentary environments by comparing fractal constants with grain size statistical analysis for the soil samples of Pohang (PH) and Namhae (NH). The y-interception of log (grain size)-log (passing) equation was also used because grain size distribution couldn't be expressed with fractal dimension only. The result of comparison between fractal constants (dimension, y-interception) and grain size statistical indices, the fractal dimension was directly proportional to the mean and the sorting. And the y-interception showed high correlation with the mean. The fractal dimension and y-interception didn't show significant correlation with the skewness and the kurtosis. Thus regression equations between fractal constants and two statistical indices (mean, sorting) were derived. All classifications of the mean and the sorting could be determined using the regression equation based on the fractal dimension and y-interception. Therefore, fractal constants could be used as an alternative index representing the sedimentary environments instead of the mean and sorting.

• Journal of Environmental Impact Assessment
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• v.18 no.3
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• pp.171-183
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• 2009

This study aims to analyze the sedimentary environment change in mid-channel bar of the lower Geum river basin after the construction of the estuary barrage using multi-temporal satellite data and GIS. The sedimentary environment changes were observed in mid-channel bar areas. The mid-channel bar F was found to have been newly formed for 10 years(1996-2006), whereas the mid-channel bar B located between mid-channel bar A and C has disappeared by erosion during the same periods. When examined by section, the areas of the mid-channel bar in the upper stream section from the Yipo's reference point generally increased due to the prevailing sedimentary environments, and those of the downstream section decreased where corrosive environments are dominant. In ternms of the centroid movement, the mid-channel bars grew up toward the downstream by switching erosion and accumulation, as sedimentation was prevailing in the downstream area of mid-channel bars and corrosion was dominant in the upper stream. Through grain size analysis, the study areas are divided into three sections according to the average grain size. In Section I, the mid-channel bars were formed as a result of sedimentary process of tides in the past. In Section II, the mid-channel bars were formed partly through the sedimentary process of rivers although the sedimentary process of tides is prevailing. In Section III, the mid-channel bars were formed mainly through the sedimentary process of rivers, even if it showed the sedimentary process of tides in the past.

• Journal of The Geomorphological Association of Korea
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• v.25 no.2
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• pp.43-61
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• 2018

Heterogeneous sedimentary deposits with different soil colors and various degree of hardness are exposed in its foredune and tidal zone due to the effects of recently accelerated coastal erosion along the Ujeon Coast in Jeung-do, Shinan-gun. This study was conducted on the assumption that these sedimentary deposits were developed in different timing and environments. Thus, we can infer the geomorphic development processes of the area based on evidences like the physicochemical characteristics of each sedimentary layer. Several analysis of these sedimentary depositssuch as grain size analysis, X-ray Fluorescence Measurement (XRF), and Loss on ignition (LOI) were performed on central (Ujeon A) and southern (Ujeon B) parts of the Ujeon Coast. I found that the foredune sedimentary deposits have four stages of geomorphic development processes. In the initial stage of development, during the peak of the Last Interglacial Period (MIS 5e), basal deposits were accumulated in the low-energy environment of subtidal zones. In the second stage, during the Last Glacial Period (MIS 4~MIS 2), eolian sedimentary layers were developed by terrestrial aeolian processes by which fine materials were transported from the Yellow Sea which became a dry land exposed by lowered sea level. In the third stage, various mechanism existed for the formation of each sedimentary layer. In the region of Ujeon A, sedimentary layers were developed in the littoral zone environment dominated by marine processes during the maximum phase of transgression in the Holocene. Meanwhile, the region of Ujeon B began to form eolian sedimentary layers during MIS 2. In the last stage, thick coastal dune deposits, covered all over the Ujeon Coast. During the late Holocene (0.7~0.6 ka), terrestrial processes kept dominating the region, developing typical eolian sedimentary layers.

• Journal of The Geomorphological Association of Korea
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• v.25 no.3
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• pp.43-55
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• 2018

This study aimed to identify different sedimentary environments of Gochang coast according to geomorphic conditions of each bore hole. To achieve the aim, this study utilized the classification of sedimentary environmental conditions of surface sediment, which was based on grain size distribution characteristics.In other words, three sedimentary environmental conditions ofsandy flat + sand beach, coastal sand dune and weathered bedrock soil, which were distinguished based on grain size distribution characteristics of mean-sorting for surface sediments, were applied to the sediments of bore holes. Four sedimentary environments could be identified in Gochang coast. First, the lake sedimentary environment originated from terrestrial sediments seems to have been dominated by weathered bedrock soil that the surface flow has deposited in a coastal wetland or a boundary, which is affected by the sea. Second, the lake sedimentary environment that is little affected by coastal sand dunes is located at the center of a valley, which is connected to the land, and the dune slack of Saban-ri. The surface flow of weather bedrock soil is the main source of deposits. However, there seems to have been a temporary influence of the sea. Third, the lake sedimentary environment that is strongly affected by coastal sand dunes is located at the dune slack of Yeongjeong-ri. This environment shows traces of a change from a coastal sand dune into the dune slack. Finally, the coastalsand dune sedimentary environment, which wasinvestigated by boring the current coastal sand dune, shows a temporary influence of the land but seems to have maintained the overall stability. Consequently, this study demonstrated that the grain size distribution characteristics of the present surface sediments could be effectively applied to identify the sedimentary environments of the paleo bore hole sediments. In addition, the paleo change of sedimentary environment could also be identified in many places of Gochang coast. If the results of this study are combined with the age dating and geochemical analysis in future works, the paleo environmental change in Gochang coast will be restored more precisely.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.140-143
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• 2004

The west coast of the Korean Peninsula is famous for its large tidal range (up to 9 m) and vast tidal flats. With comparison the sedimentary environments of open and close tidal flat using remote sensing, we select Kanghwa tidal flat and Hwang-Do tidal flat in Cheonsu Bay. Prior to surface sediment discrimination using remote sensing, sedimentary environments including intertidal OEM, hydraulic condition, and relationship between grain size and various tidal condition are investigated. Remote sensing has the potential to provide synoptic information of intertidal environments. The objectives of this study are: (i) to generate an intertidal digital elevation model (OEM) using the waterline method of Lansat TM/ETM+, (ii) to investigate the tidal channel distribution using texture analysis, and (iii) to analyze the relationship between surface grain size by using in-situ data and intertidal OEM and tidal channel density by using high-resolution satellite data such as IKONOS and Kompsat EOC. The results demonstrate that satellite remote sensing is an efficient and effective tool for a surface sediment discrimination and long term morphologic change estimation in tidal flats.

• Economic and Environmental Geology
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• v.54 no.5
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• pp.595-603
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• 2021

Sand layer distribution, which is the main target of river and land aggregate resources, mainly belongs to alluvial and river sedimentary environments among the Quaternary sedimentary environments. The distribution of aggregate resources in the area of Geumsan-gun, Chungcheongnam-do is characteristically developed around a sedimentation environment in which intrusive meandering river dominate. Although the area around Bonhwangcheon Stream and the area near the confluence of small streams are small, the river floodplain develops and corresponds to the aggregate distribution area. The sedimentary layer formed in the sedimentary environment such as colluvial deposits or alluvial fan deposits has a relatively low distribution rate of aggregate resources. The vertical distribution of the Quaternary sedimentary layers in the Geumsan-gun region ranges from about 5 to 12 m and has an average Quaternary sedimentary thickness of 8 m. The aggregate-bearing section has an average thickness of 3.6 m, and the average grain size is about 21% clay-silt, 67% sand, and 12% gravel. The main characteristics of the aggregate-bearing section are that coarse-grained sand predominates, and gravel is sub-angular or sub-rounded, and the sorting is generally poor and has a massive form of deposits, and the soil colour ranges from dark grey to yellowish-brown. In Geumsan-gun, the most likely distribution area for aggregate development is the alluvial sedimentary and river sedimentary layers distributed along the current and former riverbeds of the main Geumgang River, Bonhwangcheon and small River tributaries.

• Journal of Wetlands Research
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• v.7 no.2
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• pp.53-67
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• 2005

Cheonsu bay, which is typically a semi-closed type, is characterized by various environments such as channels, sand bars, small islands and tidal flats. The construction of Seosan A and B sea dikes from 1983 to 1985 might continuously change sedimentary environments in the northern part of the bay. In order to investigate sedimentary environment, surface and core sediments were sampled at the Hwangdo tidal flat and adjacent sea in June and October 2003. The surface sediments consisted of five sedimentary facies. Generally, the surface sediments in October were changed coarser on the tidal flat and little changed in the subtidal area compared to those in June 2003. Sedimentary facies analysis of three core sediments suggested that wave and tidal current were relatively strong in the tidal flat near Hwangdo, whereas the energy was relatively low in the tidal flat near channel. Sediment accumulation rates in the Hwangdo tidal flat during 11 months indicated that sediments deposited in the central part, whereas eroded in eastern and western sides of the tidal flat. These caused that sea dike changed tidal current patterns and sediment supplies.

• 한국해양학회지
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• v.26 no.1
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• pp.13-23
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• 1991

For the purpose of examining the depositional sedimentary environments in the Han River estuary and around the Kyunggi Bay posterior to the Han river's developments, a hydrological and sedimen-tological survey was carried out. According to the hydrological and sedimentological conditions, the studied area can be divided into 3 depositional sedimentary environments: Fluvial, Estuarine and coastal-Bay. Posterior to the Han river's developments, however, the alterations of hydrodynamic condition in the Han river have caused a substantial change of the sedimentary environments in the lower Han river and its estuary. That is, the contents of total suspended sediment anterior to the Developments decreased from 37mg/l (in the lower Han River) and 500-1750 mg/l (at the Kanghwa Bridge) to 18 mg/l and 208-1142 mg/l posterior to the developments. these changes seem to have caused the siltation near the sin-gok Underwater Dam. Thus the characters of the boundary condition between the fluvial and the estuarine environments have rapidly changed. It is considered that these changes result mainly from the construction of the two underwater dams for the maintenance of the water level of the Han river. As the estuary is a transition zone between land and sea, these changes in the Han River estuary might affect the sedimentary environments around the Kyunggi Bay. In order to verify the effects of these changes, it is necessary that a detailed survey be carried out around the Han River estuary including the Imjin and Yesong River estuaries.

• Economic and Environmental Geology
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• v.18 no.3
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• pp.289-299
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• 1985

Sedimentary petrology and depositional environments of the Sindong Group, consisting of in ascending order the Nagdong, Hasandong and Jinju Formations, in the Euiseong Subbasin are studied. For these, the Sindong sequence over 1,000m thick is measured at the scale of 1:200 and 36 thin sections of sandstones of the Hasandong Formation are studied under the polarizing microscope. In addition, published paleontologic data are incorporated in the sedimentologic interpretation. Most of the sandstones are classified as arkose. They are moderately sorted, near symmetrical to fine skewed and mesokurtic. Relationship between the textural parameters suggests a fluviatile environment of the Hasandong Formation. The Sindong fauna and flora also indicate non-marine depositional environments. Sedimentologic data of the measured sections show that the Sindong Group is made up of from the bottom an alluvial fan (lower part of the Nagdong Formation), a fluvial plain (upper part of the Nagdong Formation and the Hasandong Formation) and a fluvial/lacustrine (the Jinju Formation) deposits.

• Ocean and Polar Research
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• v.29 no.4
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• pp.411-418
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• 2007

We studied the bottom morphology and sedimentary environments of the Masan Bay using high-resolution Chirp seismic profiles and sediments data. According to deep-drilled core samples (up to 20 m thick) penetrated into the weathered rock basement, the sediments consist largely of three sediment types: the lower sandy gravel facies (Unit I) of 1-4 m in thickness, the middle sandy mud and/or muddy sand facies(Unit II) of 1-2 m thick and the upper mudfacies (Unit III) of over 10 m in thickness. The sedimentary column above the acoustic basement can be divided into two major sequences by a relatively strong mid-reflector, which show the lower sedimentary sequenc e(T) with parallel to subparallel internal reflectors and the upper sedimentary sequence(H) with free acoustic patterns. Acoustic basement, the lower sedimentary sequence (T), and the upper sequence (H) are well correlated with poorly sorted massive sandy gravels (Unit I), the sand/mud-mixed sediment (Unit II), and the muddy facies(Unit III), respectively. The acoustic facies and sediment data suggest that the Masan bay is one of the most typical semi-enclosed coastal embayments developed during the Holocene sea-level changes. The area of the Masan Bay reduced from about $19\;km^2$ in 1964 to about $13\;km^2$ in 2005 by reclamation, and its bottom morphology changed as a result of dredging of about $2{\times}10^7\;m^3$.