• Title/Summary/Keyword: 단구면 분류

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Geomorphological Development and Paleoenvironment around Sinsong-ri, Gobuk-myeon, Seosan-si, South Korea (서산시 고북면 신송리 유적 일대의 지형 발달과 고환경 분석)

  • Hwang, Sang-Ill;Kim, Hyo-Seon;Yoon, Soon-Ock
    • The Korean Journal of Quaternary Research
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    • v.24 no.2
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    • pp.23-34
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    • 2010
  • The purpose of this study is to clarify the characteristics of geomorphic surfaces and investigate their geomorphological development at Sinsong-ri archaeological sites by the classification of geomorphic surfaces. The sedimentary facies of trench 1, 2 and 3 were identified and pollen analysis was performed at site 3. The geomorphic surfaces are classified by hillslope, valley plain, alluvial fan and river terrace. Most of the study area is located on low hillsides and valley plains are connected with tidal flats extended from small river valley. Also, alluvial fans are distributed over the piedmont and narrow, long river terraces are developed downstream along the Sojeong-stream flowing between valley plain and hillsides. River valleys were deeply eroded during the Last Glacial Maximum (LGM) periods, responded to the lowest sea level among the hillslopes and valley plains are formed during the Holocene. The sedimentary facies are identified composed of basal gravel layers with coarse gravels and sands, relatively thick culture layer of the Bronze Age and thin layer during the early Iron Age in upper part study area. Thus, land uses during the Bronze Age people was performed more intensively comparing to the early Iron Age by deforestation for habitation.

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Paleo-red Soil on the High Fluvial Surface in the Middle Basin of Nam-Han River (남한강 중류 하성고위면의 고적색토)

  • Kang, Young-Pork;Lee, Sang-Min
    • Journal of the Korean earth science society
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    • v.26 no.8
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    • pp.828-835
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    • 2005
  • The purpose of this study is to clarify the landform development of fluvial terrace and the soil characteristics occurring on the terrace deposit. In order to achieve the purpose, the characteristics of soil profiles, the physic-chemical properties of soils that are developed on terrace deposits and X-ray diffraction analysis of clay were investigated. The horizon of Al in the high fluvial surface is silt clay loam of red (2YR 4/6). The soil structure is a developed granular structure. The horizon of B1 is silt clay reddish-brown (2.5YR 4/6). The soil structure is a medium subangular blocky structure. This red soil structure is made on heavy textured and compactly packed parent materials of high terrace sediments and usually has A-B-C profile. In most cases, clay accumulations in B-horizon and clay cutans on ped surfaces are observed, which mean the formation of agrillic horizon. As the result of this study, soils derived from fluvial terrace deposits on high fluvial surfaces are considered paleo-red soil which were developed by pedogenese-strong desilicification and rubefaction and strong leaching of bases- under warmer bio-climatic condition during in the old Pleistocene period.

The Changing Process of the Tidal Landforms in Hampyeung Bay, Southwest Korea (함평만의 간석지 해안지형의 변화)

  • KIM, Nam-Shin;LEE, Min-Boo
    • Journal of The Geomorphological Association of Korea
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    • v.18 no.4
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    • pp.223-233
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    • 2011
  • The aims of this study is about distribution characteristics of tidal coastal landforms, and that changing process in the Hampyeung Bay, which has a semi-enclosed bay like basin shape without inflow of stream, the mouth of open sea is narrow and forms with wide ends toward inland sea. The source of deposits are moved materials by tidal currents and from coastal slopes. Main landform elements of study area consist of tidal flat, tidal channels, intertidal sand bar, sea cliffs, and sea terrace. Tidal flats is classified with mud flat and mixed flat by grain size composition. Mud flats have developed at the shoreline area that tidal flat is closed to the continuity of gentle slope, and mixed flat developed at the foot of the sea cliffs and sea terraces. Quaternary deposits were identified in the coastal materials sedimented by the sea-level change. According to the analysis of grain size composition during last ten years, sands and silt has increased 2% and 6% respectively, clay has been decreased by 9%. The concaved tidal flats are colonized by salt plants. Areal changes of salt plants expanded near four times from 2.4km2 at the year 2001 to 9.3km2 at the year 2009. During the same periods, mean grain size became coarser from 6.5φ to 4.5φ at the salt plants area.

Pollen morphology of Patrinieae Höck (Valerianaceae) (마타리족(Patrinieae Höck, 마타리과)의 화분형태학적인 연구)

  • Jung, Eun-Hee;Hong, Suk-Pyo
    • Korean Journal of Plant Taxonomy
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    • v.38 no.2
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    • pp.163-177
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    • 2008
  • Pollen grains of 17 taxa (14 species with two additional subspecies and one variety) of genera Patrinia Juss. and Nardostachys DC. in tribe Patrinieae (Valerianaceae) were studied using light microscope, scanning electron microscope, and transmission electron microscope. Pollen grains are medium ($37.41{\times}43.60{\mu}m$ - $45.65{\times}48.50{\mu}m$) to large ($54.88{\times}59.41{\mu}m$ - $61.70{\times}71.00{\mu}m$) in size, tricolpate (rarely tetracolpate) with the characteristic halo surrounding the aperture. In equatorial view, the pollen is oblate to subprolate, and in polar view, it is mostly circular or rarely 3-lobed. Two major pollen types are recognized on the basis of exine sculpturing patterns; Type I: Exine is composed of echinae together with sparse or dense microechinae, and verrucae shallow or rarely absent (Nardostachys and sections Paleopatrinia, and Monanadropatrinia of Patirinia). - Type II: Exine is composed of massive echinae together with dense microechinae, and prominent verrucae (section Centrotrinia of Patrinia). In TEM sections, columellae are extended from the footlayer into verrucae, and exine thickness is uniform at the pole and equator. Additionally, the infrageneric classification systems of the Patrinieae were evaluated on the basis of the present data.

Field Evidence of Magma Mixing from Concentric Zoning and Mafic Microgranular Enclaves in Bunam Stock, Korea (청송 부남암주의 동심원상 누대와 포유체로부터 마그마 혼합작용의 야외증거)

  • Hwang, Sang Koo;Seo, Seung Hwan
    • The Journal of the Petrological Society of Korea
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    • v.25 no.4
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    • pp.349-360
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    • 2016
  • The Bunam Stock ($29.5km^2$ area) is an outcrop of plutonic complex classified four facies: coarse-grained granite, quartz monzodiorite, granodiorite and fine-grained granite. Three facies except the last one exhibit very irregular boundaries with gradational compositional variations between both facies and show concentric zoning from the central quartz monzodiorite through granodiorite to outer coarse-grained granite. Mafic microgranular enclaves (MME) commonly occur in granodiorite. Some MMEs, have very fine-grained chilled margins and indentedly crenulate contacts, and display horizontally circular and vertically elongate shapes. Their shape and granularity indicate coeval flow and mingling of partly crystalline felsic and mafic magmas. MMEs exhibit dark fine-grained margins giving them a ellipsoidal form that has been attributed to undercooling of a mafic magma as blobs intruded into a felsic magma. The observed relations in the Bunam Stock identify that two endmembers are coarse-grained granite from a felsic magma and quartz monzodiorite from a mafic magma, and hybrid is granodiorite including MMEs. So they exhibit concentric zoning that lays the center on the mafic endmember due to magma mixing at the contacts of two magmas, when mafic magma injected into felsic magma. Thus the quartz monzodiorite may probably represent an ancient conduit of mafic magma transport through a granitic magma chamber. Mafic magma would rise through the conduit in which favorable conditions for magma mixing occurred. All these features suggest that they formed from mixing processes of calc-alkaline magma in the Bunam Stock.

Updating DEM for Improving Geomorphic Details (미기복 지형 표현을 위한 DEM 개선)

  • Kim, Nam-Shin
    • Journal of the Korean Association of Geographic Information Studies
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    • v.12 no.1
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    • pp.64-72
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    • 2009
  • The method to generate a digital elevation model(DEM) from contour lines causes a problem in which the low relief landform cannot be clearly presented due to the fact that it is significantly influenced by the expression of micro landform elements according to the interval of contours. Thus, this study attempts to develop a landcover burning method that recovers the micro relief landform of the DEM, which applies buffering and map algebra methods by inputting the elevation information to the landcover. In the recovering process of the micro landform, the DEM was recovered using the buffering method and elevation information through the map algebra for the landcover element for the micro landform among the primary DEM generation, making landcover map, and landcover elements. The recovering of the micro landform was applied based on stream landforms. The recovering of landforms using the buffering method was performed for the bar, which is a polygonal element, and wetland according to the properties of concave/convex through generating contours with a uniform interval in which the elevation information applied to the recovered landform. In the case of the linear elements, such as bank, road, waterway, and tributary, the landform can be recovered by using the elevation information through applying a map algebra function. Because the polygonal elements, such as stream channel, river terrace, and artificial objects (farmlands) are determined as a flat property, these are recovered by inputting constant elevation values. The results of this study were compared and analyzed for the degree of landform expression between the original DEM and the recovered DEM. In the results of the analysis, the DEM produced by using the conventional method showed few expressions in micro landform elements. The method developed in this study well described wetland, bar, landform around rivers, farmland, bank, river terrace, and artificial objects. It can be expected that the results of this study contribute to the classification and analysis of micro landforms, plain and the ecology and environment study that requires the recovering of micro landforms around streams and rivers.

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