• Title/Summary/Keyword: 고환경복원

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Reconstruction of the Paleo-environment during the Upper Pleistocene at Seongjeong-dong, Cheonan-si, inferred from Pollen Analysis (천안 성정동 지역의 화분분석 결과를 통한 Pleistocene 후기 고환경복원)

  • Kim, Hye-Ryung;Yoon, Soon-Ock;Hwang, Sang-Ill;Lee, Byeong-Cheol
    • Journal of the Korean Geographical Society
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    • v.47 no.2
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    • pp.179-192
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    • 2012
  • Paleo-environments such as vegetation and climate changes from the Last Glacial Maximum to the Holocene are reconstructed by the results of pollen analysis in the floodplain of Cheonan River, Seongjeong-dong, Cheonan-si, Chungnam Province. In the pollen zone I (approximately 23,000-15,000 yr BP), the area studied was covered by the extensive grassland with sparse wood. The climatic conditions were very cold, but it might not be so severe compared to the intermontane area in the Yeongnam area. This zone corresponds to the 'very cold' stage of Woldstedt(1962) and Yoon and Jo(1996). No pollen horizon(pollen zone II) deposited between approximately 15,000 and 10,000 yr BP corresponds to the transitional stage from the Last Glacial Maximum to the Holocene. The horizon consists of the dark gray brown sand deposits different from the other horizons dominated by the silty deposits and these sedimentary properties may be attributed to the dramatic climate changes between the very cold stage and warm stage. The pollen zone III formed between approximately 10,000 and 6,000 yr BP shows clearly different pollen compositions indicative of temperate climate conditions.

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Reconstruction of the Paleo-Environment Since the Middle Holocene Using Pollen Analysis at Yulha-dong, Kimhae-si, South Korea (김해 율하 지역 화분분석을 통한 홀로세 중기 이래 고환경 복원)

  • Hwang, Sangill;Hwang, Beomjin;Yoon, Soon-Ock
    • Journal of The Geomorphological Association of Korea
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    • v.24 no.2
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    • pp.51-64
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    • 2017
  • The paleo-environments including changes in vegetation, climate, and sea level since the middle Holocene(6,400(?)-1,800(?) yr BP) were reconstructed with the special reference to pollen analysis from two trench samples at Yulha-dong, Kimhae-si, southern Korea. The environmental characteristics by the pollen zonation wassummarized asfollows: Pollenzone I(6,400(?)~3,940(?) yr BP)showed the dominance of Quercus species with broad-leaved trees, it was warm condition. Pollenzone II(3,940(?)~2,300(?) yr BP) was characterized to the yellow soil indicating terrestrial environment. Moreover, it showed Alnus-NAP period related to the extension of agriculture and deforestation by the rapid decrease of Quercus and increase of Gramineae. Pollenzone III(2,300(?)~1,800(?) yr BP) showed human impact from the increase of NAP and Pinus. Plenty of Quercus with deciduous broad-leaved trees also suggested warmer condition than before.

The Geomorphic Characteristics and Late-Holocene Paleoenvironmental Reconstruction in Sejong-Si Based on the Pollen Analysis of the Right Bank of Geumgang (세종시 금강 우안(右岸)지역의 지형특성과 홀로세 후기 고환경복원)

  • Moon, Youngrong;Yoon, Soon-Ock;Hwang, Sangill
    • Journal of The Geomorphological Association of Korea
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    • v.24 no.4
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    • pp.1-12
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    • 2017
  • This study tried to reconstruct paleovegetation environments during the late Holocene with pollen analysis from archeological trenches at the right bank of Geumgang in Sejong-si. The lower hills was dominantly covered with pine trees, while alder trees and hygrophytes extended on the floodplain since 2,000yr BP. The pollen composition of Alnus dominance in the floodplain during the times is different from the general charateristics of Korean peninsula. Such a phenomenon is thought to be influenced by the fluvial process on the floodplain in the middle reaches of Geumgang around Sejong-si. Mihocheon and some tributaries join to Geumgang around Sejong-si, and the channel of Geumgang becomes narrow around the boundary between Sejong-si and Gongju-si. This narrow channel could attribute to the formation of extensive floodplain around Sejong-si. Moreover, human impacts such as agriculture appear continuously since 1,800yr BP.

Discussion about Characteristics and Study Results of Phytolith for the Quaternary Paleoenvironmental Reconstruction (제4기 환경복원을 위한 식물규소체의 특성과 연구 성과에 대한 논의)

  • HWANG, Sangill;KIM, Hyo-Seon;YOON, Soon-Ock
    • Journal of The Geomorphological Association of Korea
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    • v.17 no.3
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    • pp.1-16
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    • 2010
  • Phytoliths, silica microfossil that produced within and between cells and tissues of plants are especially yielded in Gramineae with many different forms and can attribute to the reconstruction of climatic and environmental changes and agriculture activity of the Quaternary. The phytoliths in soil can remain for long periods of time, because of strong resistance to physical and chemical weathering. The spatial range of study is too small due to deposition of phytoliths directly to the soil. There are difficulties of phytoliths identification because of multiplicity and redundancy, so far uniform and exact classification scheme has not been adopted. Therefore we attempted phytolith classification system applied to Korea. The paleoenvironmental reconstruction research using phytholith are applicated in many parts of studies. Also high-resolution paleoclimatic reconstruction expected to be possible using phytolith indices of Iph and Ic as well as climatic indicator of phytolith morphology.

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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