• Title/Summary/Keyword: Fluvial-swamp

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Development of Holocene Unconsolidated Stratigraphic Sequence from Lower Reaches of Nagdong River, Dongup Area (동읍지역 제4기 미고결 지층의 퇴적이력)

  • Kim, Sung-Wook;Choi, Eun-Kyeong;Lee, Seong-Hoon;Lee, Seung-Won;Han, Seok-Hee;Cho, Sang-Soon;Jun, Whi-Chae
    • Proceedings of the Korean Geotechical Society Conference
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    • 2006.03a
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    • pp.876-881
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    • 2006
  • This study was carried out to understand depositional environment and genesis of clayey soils that distributed in the Dongup area. On the basis of detailed observation and description on mineralogy, geochemical composition, geophysical properties, paleontological analysis of cored sediments, three sedimentary unit have been distinguished. From bottom to top, they are early Holocene freshwater muddy deposit(Unit I, fluvial swamp), late Holocene silt and muddy deposit(Unit II, alluvial deposit), late Holocene muddy deposit(Unit III, fluvial swamp). Unit II is divided into three part: the lower part-unweathered massive silt and muddy deposit, middle part-weathered layered slit and muddy deposit and upper part-weathered massive muddy deposit.

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Rethinking of Quaternary deposits and implication of rice seeds in Cheongju Sorori Site, Korea (청주 소로리 유적의 제4기 퇴적층과 볍씨 출토의 의미 재고찰)

  • Ju Yong Kim;Dong-Yoon Yang;Sangheon Yi;Wook-Hyun Nahm
    • The Korean Journal of Quaternary Research
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    • v.31 no.2
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    • pp.13-22
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    • 2017
  • The age of the Sorori old fluvial deposits is assumed as old as Last Interglacial(MIS 5) when appying the thalassostatic terrace formation in mid- to downstream Keum river basin, while the young fluvial deposits are interpreted to be formed since the post-LGM(last glacial maximum), including both the Bølling-Allerød (B/A) Interstadial(12,700~14,700 cal-yrBP), and the Younger Dryas Stadial(11,700~12,900 cal-yrBP). The wild rice seed like Oryza rufipogon found in the middle organic muds of the young fluvial deposits dated after about 15,000 cal-yrsBP, when the transition from the subalpine conifer forest to the deciduous broad-leaved forest was conspicuously evidenced in the upper part of OC-2 palynofloral zone of the in Cheonju Sorori site, In particular the OC-2 palynofloral zone ranging towards the upper part of middle organic muds(peaty muds) is interpreted to be formed in the B/A Interstadial. It is regarded that Cheongju Sorori rice seeds are associated with warm palynological evidences and backswamp insects during the Lastest Glacial, showing appearance of relatively warm climate similar to the present.

Diagnosis of Vegetation for the Ecological Rehabilitation of Streams - The Case of the Namhan River - (하천의 생태적 복원을 위한 식생학적 진단 - 남한강을 중심으로 -)

  • Myung, Hyun;Kwon, Sang-Zoon;Kim, Chang-Hwan
    • Journal of the Korean Institute of Landscape Architecture
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    • v.30 no.5
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    • pp.98-106
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    • 2002
  • This study was designed to present a river model with the aim of restoring the ecosystem and improving the landscape along the urban rivers on the basin of the Namhanl river, a core life channel for the National Capital regin. The revelation of botanical status, transition trend and correlation of plants might lead to providing the urban river restoration projects and ecological river formation projects with basic data for a model of ideal aquatic ecology and landscape. The outcomes of this study could be summed up as follows: 1. The plant communities of river flora found on the basin of the Namhan river could be categorized largely into 39 plant communities 2. Most diverse plants were distributed in the rivers lower reaches such as Unsim-ri where the protected zone of Paldang reservoir for city water borders the body of Jodae swamp where natural streams flow nearby. 3. One of the greatest threats to the biomass of the River Namhan is that the communities of such invasive alien plants as Panicum dichotomiflorum and Ambrosia artemisiifolia var. elatior dominate most parts of the area, a fact that has resulted in a reduced variety of plants and will, sooner or later, be likely to cause an ecological imbalance in the hitherto healthy Aquatic plant life. It is highly advisable to gradually diversify the species of trees and to return the plants bark to their original state since, besides the naturalized plants, plantations afforested with Erigeron canadensis and Erigeron annuus stocks in buckwheat field, Robinia Pseudo-accacia in riverside forest, Pinus rigida in terrestrial forest on the river basin and Larix leptolepis are anticipated to act as interceptors of normal migrations of the fluvial and terrestrial ecosystems. Finally, it seems also desirable to continue to explore the relationship between fluvial and terrestrial ecologies with the purpose of building up a model of natural streams in urban areas based on the surveyed factors for plant life, soil and landscape and, moreover, on the forecasting for overall influences derived from the rotation upon the ecosystem.

Late Quaternary Stratigraphy and Depositional Environment of the Coastal Sediments along Moonamni, Kangwon Province, Korea (강원도 동해안 문암리 해안지층의 제4기 후기 퇴적층서화 환경)

  • 박용안;김수정
    • The Korean Journal of Quaternary Research
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    • v.15 no.1
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    • pp.29-35
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    • 2001
  • The coastal deposits along Moonamni, Kangwon Province, Korea have been investigated by using deeply cored sediments(down to the basement rocks : Pre-Cambrian metamorphic rocks and granitic rocks) in order to understand and propose the late Quaternary stratigraphy and related major unconformities. Three major stratigraphic -depositional units are proposed. The neolithic cultural sites in the Moonamni area are considered as middle Holocene coastal dunes, which were developed due to active supply of beach sands from Unit I(Holocene transgressive deposit). Such coastal dune sediments are characteristic in the upper part of Unit I(Holocene in age). So far, Unit II and Unit III are considered as continental deposits, such as fluvial-swamp and alluvial deposit, respectively.

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Discussion on the Metasequoia Fosslis from the Miocene Keumkwandong Formation of the Janggi Group, Korea (포항분지의 마이오세 장기층군의 금광동층에서 산출된 메타세콰이아(Metasequoia) 화석에 대한 고찰)

  • Kim, Jong-Heon;Choi, Seung-Il
    • Journal of the Korean earth science society
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    • v.29 no.4
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    • pp.319-327
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    • 2008
  • A paleobotanical study of the Metasequoia has been carried out from the Miocene Keumkwangdong Formation of the non-marine Janggi Group in the Pohang Basin. As a result of this study, deciduous leafy shoots mostly belong to a single species of Metasequoia occidentalis. This species is characterized by its opposite leaves with decurrent base, and by its presence of scale leaf at base of petiole. This species is common in the Korean Tertiary floras in Miocene age, yet it has not been recorded in the Korean Peninsula after Miocene. Based on the distribution and ecology of extant Metasequoia. it is considered that the Metasequoia might have flourished in the fluvial plains as swamp forest.