• Title/Summary/Keyword: geomorphic surface

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The Function or Urban River and Sustainable Regional Development : The Case of Kumho River (도시하천과 지속가능한 지역 발전 : 금호강을 중심으로)

  • Choi, Byung-Doo
    • Journal of the Korean association of regional geographers
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    • v.10 no.4
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    • pp.757-774
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    • 2004
  • This paper is to reclassify systematically the functions of urban river: that is, water supply, land management, transportation and energy source as social and economic function; formation of geomorphic surface, water-side landscape, community constitution and boundary and separation between regions as spatial function; and drainage of waste water, purification, habitation, and weather regulation as ecological function. On the basis of this reclassification, it can be argued that the socio-economic functions (eg. water supply) of the river among the functions of the river have been strongly mobilized in the process of modernization, while the spatial function and ecological function of urban river have been ignored. The Kumho river which flows through Daegu and the adjacent area has made a great contribution to the modem development process of the river basin area, but as a result of a selective development of a specific function of the river, that is the social and economic function, it now suffers from the lack of instream flow and is deprived of its original functions with the water pollution and degradation. Moreover the Daegu region seems no longer possible to develop on the dependence of the river. In order to overcome this kind of social and environmental crisis, this paper is to suggest both some principles and main evaluating indicators to restore the original and comprehensive functions of the river, and important measures to make the co-evolution of the city and the river possible.

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Lineament and Fault-related Landforms of the Western Chungcheongnamdo (충남 서부지역의 선형구조와 단층지형)

  • Tae-Suk Kim;Cho-Hee Lee;Yeong Bae Seong
    • Journal of the Korean earth science society
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    • v.45 no.3
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    • pp.224-238
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    • 2024
  • This study analyzed lineaments and fault-related landforms in Chungcheongnam-do, central Korean Peninsula, based on historical and instrumental records, given its susceptibility to future earthquakes. We extracted 151 lineaments associated with fault-related landforms. In regions with the Dangjin and Yesan faults, lineaments with strikes matching these faults were densely distributed. Conversely, in the Hongseong Fault area, the number of lineaments was smaller, and those with strikes similar to the fault were less discernible. This is likely due to the extensive distribution of alluvium and surface deformation from long-term weathering, erosion, and cultivation, which obscures geomorphic evidence of faults. At five key fault points, we identified fault-related landforms, such as fault saddles, knickpoints in Quaternary alluvium, and linear valleys, along the lineament, which may indicate an actual fault. However, the displacements of the Quaternary layer within the lineaments appear to be influenced more by external factors, such as artificial disturbances (e.g., cultivation) or stream erosion, than by direct fault movement. The differences between the fault-related landforms in this study area and those in the southeastern Korean Peninsula suggest a specific relationship between fault types and their associated landforms.

Characteristics of Recent Foraminifera and Surface Sediments in Gomso- Bay Tidal Flat, West Coast of Korea: Potential for Paleoenvironmental Interpretations (곰소만 조간대의 현생 유공충과 표층 최적물의 특성: 고환경 해석에 적용 가능성)

  • 우한준;장진호
    • 한국해양학회지
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    • v.30 no.3
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    • pp.184-196
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    • 1995
  • The line-SW is located in the mouth of Gomso Bay (20 Km long and 5-8 Km wide),west coast of Korea. This area is composed of sand flat, mud flat, sand shoal and chenier, The difference of physical, geological and geomorphic conditions in subenvironments of the bay may control and produce distingtive foraminiferal populations and assemblages. This study investigates whether five a priori subenvironments (five local zonations) in Gomso-Bay tidal flat can be distinguished from each other on the basis of total (living plus dead) foraminiferal assemblages. Seventy-four species (67 benthic; 7 planktonic) were recorded in total assemblages of surface sediments from 10 stations. Ammonia beccarii tepida, Discorbis candeiana, Elphidium etigoense and Eponides nipponicus were most dominant species in living and total assemblages. The relative abundance (%) of living population was high at upper flat and decreased from upper to lower flat. The low percentages of living populations in middle to lower flat are probably influenced by the decreasing reproduction of foraminifera caused by high energy condition and addition of dead species from offshore. The occurence of planktonic foraminifera in middle to lower flat (5.3∼6.6%) indicates introduction of planktonic foraminifera from offshore by storm and/or tidal current. The relatively high numbers of species in lower middle to lower flat are probably caused by a mixing of faunas from these areas and offshore. The high numbers of total individuals per 50 ml of sediment in upper flat indicate that this area is a relatively stable environment where waves and currents are protected by the chenier. Five biofacies of the total foraminiferal assemblages were established on the basis of dominant species (those representing more than 20% of the total assemblages in any station) in the five a priori subenvironments recognized along the Line-SW transect in Gomso-Bay tidal flat. Five biofacies are potentially useful in paleoenvironmental interpretation in late Quaternary Gomso-Bay tidal deposits.

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Taxonomical Classification and Genesis of Cheongpung Series Distributed on Diluvial Terrace (홍적대지 토양인 청풍통의 분류 및 생성)

  • Song, Kwan-Cheol;Hyun, Byung-Geun;Sonn, Yeon-Kyu;Zhang, Yong-Seon;Park, Chan-Won;Jang, Byoung-Choon
    • Korean Journal of Soil Science and Fertilizer
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    • v.43 no.2
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    • pp.224-229
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    • 2010
  • This study was conducted to reclassify Cheongpung series based on the second edition of Soil Taxonomy, and to dicuss the formation of Cheongpung series distributed on the diluvial terrace. Morphological properties of typifying pedon of Cheongpung series were investigated, and physico-chemical properties were analyzed according to Soil survey laboratory methods manual. The typifying pedon of Cheongpung series has red (2.5YR 4/6) silty clay loam Ap horizon (0-18 cm), red (2.5YR 4/8) clay BAt horizon (18-35 cm), red (2.5YR 4/2) cobbly clay Bt1 horizon (35-65 cm), and red (2.5YR4/6) cobbly clay Bt2 horizon (more than 65 cm). The typifying pedon has an argillic horizon from adepth of 18 to more than 65 cm, and a base saturation (sum of cations) of less than 35% at 125 cm below the upper boundary of the argillic horizon. It can be classified as Ultisol, not as Alfisol. It has udic soil moisture regime, and can be classified as Udult. Also that meets the requirements of Typic Hapludults. It has 35% or more clay at the particle-size control section, and have mesic soil temperature regime. Therefore Cheongpung series can be classified as fine, mesic family of Typic Hapludults, not as fine, mesic family of Ultic Hapludalfs. Cheongpung series occur on moderately elevated diluvial terrace which have relatively stable geomorphic surface. They are developed as Ultisols with clay mineral weathering, translocation of clays to accumulate in an argillic horizon, and leaching of base-forming cations from the profile for relatively long periods under humid, and temperate climates in Korea.

High-Resolution of Paleoenvironmental Reconstruction and Sea-Level History in Delaware Bay, the East Coast of U.S.A. (미국동부 델라웨어만의 고정밀도 해수면 역사와 고환경 복원)

  • YI, HI-IL;WEHMILLER, JOHN F.
    • 한국해양학회지
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    • v.30 no.4
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    • pp.320-331
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    • 1995
  • The closely spaced cores were analyzed to find detailed reconstruction of paleoenvironments and sealable changes along the Delaware Bay coast. Three areas, Kitts Hummock Beach mars, the St. Jones River marsh, and Bowers marsh near the St. Jones River's mouth, were chosen because these areas are compose of their own geomorphic characteristics and sea-level history. since significance of the stratigraphic correlations was to determine sedimentary fancies and paleoenvironments, multidisciplinary methods such as lithological description, grain-size analysis, organic/inorganic content, water content, mineral composition, botanical analysis, micropaleontological analysis, and /SUP 14/C datings were performed. Five major divisions of marsh environments were recognized in the stratigraphic sections: freshwater marsh, initialfreshwater marsh, slightly brackish marsh, brackish marsh, and salt marsh. Most of the lower part in the stratigraphic sections show freshwater marsh. On the top of this, either brackish marsh or tidal flat/tidal stream was recorded. The pro-Holocene sediments consist of sand, mud, and sandy mud, The pre-Holocene configuration played an important role for developing the Holocene Paleoenvironmental changes. The irregular configuration of the pre-Holocene sediments consist of sand, mud, and sandy mud. The pre-Holocene configuration played an important role for developing the Holocene Paleoenvironmental changes. The irregular configuration of the pre-Holocene surface within short distances permitted the concurrent development of variable environments such as freshwater marsh, brackish marsh or salt marsh at similar elevations. The freshwater marsh in this case was formed in the areas of isolation, so saline-water cannot encroach upon these areas. This complex development of paleoenvironments leads to a difficulty in stratigraphic correlation and interpretation of local relative sea-level changes. The deposition of subsurface sediments was affected by sediment supply, compaction, fluvial activity, biological competition, local tectonics and isostacy, climate and local relative sea-level changes. It was interpreted that the positions in the changes from freshwater environments to brackish environments or ice versa are the turning points of transgressions and regressions. Therefore, multiple transgressions and regressions were identified in the stratigraphic sections of the study area.

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Seasonal Morphodynamic Changes of Multiple Sand Bars in Sinduri Macrotidal Beach, Taean, Chungnam (충남 태안군 신두리 대조차 해빈에 나타나는 다중사주의 계절별 지형변화 특성)

  • Tae Soo Chang;Young Yun Lee;Hyun Ho Yoon;Kideok Do
    • Journal of the Korean earth science society
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    • v.45 no.3
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    • pp.203-213
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    • 2024
  • This study aimed to investigate the seasonal patterns of multiple bar formation in summer and flattening in winter on the macrotidal Sinduri beach in Taean, and to understand the processes their formation and subsequent flattening. Beach profiling has been conducted regularly over the last four years using a VRS-GPS system. Surface sediment samples were collected seasonally along the transectline, and grain size analyses were performed. Tidal current data were acquired using a TIDOS current observation system during both winter and summer. The Sinduri macrotidal beach consists of two geomorphic units: an upper high-gradient beach face and a lower gentler sloped intertidal zone. High berms and beach cusps did not develop on this beach face. The approximately 400-m-wide intertidal zone comprises distinct 2-5 lines of multiple bars. Mean grain sizes of sand bars range from 2.0 to 2.75 phi, corresponding to fine sands. Mean sizes show shoreward coarsening trend. Regular beach-profiling survey revealed that the summer profile has a multi-barred morphology with a maximum of five bar lines, whereas, the winter profile has a non-barred, flat morphology. The non-barred winter profiles likely result from flattening by scour-and-fill processes during winter. The growth of multiple bars in summer is interpreted to be formed by a break-point mechanism associated with moderate waves and the translation of tide levels, rather than the standing wave hypothesis, which is stationary at high tide. The break-point hypothesis for multi-bars is supported by the presence of the largest bar at mean sea-level, shorter bar spacing toward the shore, irregular bar spacing, strong asymmetry of bars, and the 10-30 m shoreward migration of multi-bars.