• Title/Summary/Keyword: 강 석

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Late Quaternary Stratigraphy and Depositional Environment of the Yeongsan River Estuary, Southwestern Korea (영산강 하구의 제4기 후기 층서 및 고환경)

  • 남욱현;김주용;양동윤;홍세선;봉필윤;이윤수;유강민;염종권
    • Economic and Environmental Geology
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    • v.36 no.6
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    • pp.545-556
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    • 2003

  • Detailed interdisciplinary investigations demonstrate that the Yeongsan River estuarine-filled sediments clearly record important paleoenvironmental changes during the Last Glacial and Holocene. The sediments from 18.9 m(20.5∼l.6m in depth) long core MW-1 are differentiated by changes in sedimentary textures and palynomorph assemblages. Chronology was provided by AMS$^{14}$C dating and regional pollen correlation. Three paleoenvironrnental phases are recognized: (1) The Last Glacial deposits consist mainly of fluvial sediments and paleosols, experienced deposition alternating with pedogenesis. The appearance of the paleosols suggests that the paleoclimate might be cold and humid. (2) The early and middle Holocene phase started abruptly in response to the rapid global climatic warming. and is characterized by abundant marine palynomorphs. (3) The late Holocene is marked by more cool conditions. The paleoenvironmental changes recorded in the sediments coincide not only with local but also with broad-scale, probably global climate changes.

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Geochemical Relationship Between Stream Sediments and Regional Geology of the Upstream for the Hahn River Drainage Basin, Korea. (한강상류 하상퇴적물과 인근유역육상지질과의 지화학적 상관관계)

  • 이연희;지정만;오재경
    • Economic and Environmental Geology
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    • v.37 no.2
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    • pp.153-171
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    • 2004

  • This study was carried out to define the geochemical and mineralogical relationship between stream sediments and regional geology on upstream of Hahn river area. Geochemical characteristic including for major elements, trace elements and rare earth elements of the South and North Hahn river bed sediments are similar to those of acid igneous rocks which are distributed around both Hahn river basin. The chemical variation of major elements against SiO$_2$ and trace elements contents between South and North Hahn river bed sediments doesn't show the difference. REE patterns of both area show a distinct negative Eu anomaly, but total contents of rare earth elements are higher in North Hahn river sediments than South Hahn river sediments. The heavy minerals in the river bed sediments in this study area are identified as tremolite-actinolite, hematiteㆍmagnetite, common hornblende, ilmenite, garnet, epidote, rutile and sphene. In conclusion, it is elucidated that South and North Hahn river bed sediments are being originated from igneous rocks or metamorphic rocks which contains medium-high grade metamorphic minerals and components of originated from sedimentary rocks those of politic or calcareous rocks are eroded away as solution or suspended load.

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