• Title/Summary/Keyword: exoscopy

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A Study on the Distribution and Changes of Sand Dune at the Lower Reach of Duman River, North Korea (두만강 하류 사구의 분포와 변화에 관한 연구)

  • Lee Min-Boo;Kim Nam-Shin;Lee Gwang-Ryul;Han Uk;Jin, Shizhu
    • Journal of the Korean Geographical Society
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    • v.41 no.3 s.114
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    • pp.331-345
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    • 2006
  • This study deals with geomorphological process of the sand dune landform including the distribution and surface environments, characteristics of sediments, origins and moving processes in lower reach and mouth delta of Duman River, Northeast Korea and China. The methodology of the study includes image analysis of Landsat TM(1992.10) and ETM(2000.9) and Spot(2005.4) for analysis of land cover, 2 times field survey for recognition of landform and acquisition of sediments raw data materials, and grain analysis and exoscopy about raw data materials. The geomorphic elements from satellite image analysis are composed of the delta, sand spit, active and stable dune, sand bar and riparian vegetated zone. Results of the grain analysis indicate the sediments originated from marine coastal zone than riverine one. This means that present sand dune not so much reflect present climatic and geomorphic environments. Result of the exoscopy analysis show that ratio of quartz, which is comparatively resistant to environment, is highest as $65{\sim}83%$ out of sediments. But the surface of the $30{\sim}40%$ of mineral grains was coated by yellow-colored stained materials, due to chemical weathering. Some grains show rough skin, looking as acicular, network structure and etching pits, affected by physical and chemical weathering.