• Title/Summary/Keyword: Coastal terrace

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Properties of Deposits and Geomorphic Formative Ages on Marine Terraces in Gwangyang Bay, South Sea of Korea (광양만 일대 해안단구의 퇴적물 특성과 지형 형성시기)

  • Lee Gwang-Ryul;Park Chung-Sun
    • Journal of the Korean Geographical Society
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    • v.41 no.3 s.114
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    • pp.346-360
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    • 2006
  • In order to analyze synthetically geomorphological processes of marine terrace in Korea, this study deals with the distribution of marine terraces, stratification of sedimentary layers, physicochemical properties of deposits, and formative ages of marine terraces based on OSL(Optically Stimulated Luminescence) absolute age at coastal area of Gwangyang Bay in central part of the South Coast. As a result of comparison with physicochemical properties on diverse geomorphic materials, there is not enough distinction in them, because of recycling and mixing of materials at Gwangyang Bay having a geomorphic closure. In Gwangyang bay coast, marine terraces are discovered at least 3 levels and have a small area. Formative age of 1st Terrace, as the lowest level ranging in $10{\sim}13m$ above the sea level, is estimated at MIS(Marine Isotope Oxygen Stage) 5a, based on OSL age dating and properties of deposits. Uplifting rate is calculated at 0.141m/ka in Gwangyang bay coast. For application to this rate, 2nd terrace($18{\sim}22m$) is estimated at MIS 5e, 3rd terrace($27{\sim}32m$) is latter part of MIS 7. Consequently, we might conclude that uplifting and geomorphic process of marine terrace in South Coast is similar to East Coast during the Late Pleistocene in Korea.

The Geomorphological Development of Coastal Terraces at Jigyeong-Ri, the Areal Boundary between Gyeongju- and Ulsan City on the Southeast Coast of Korea (한국 남동해안 경주-울산 경계지역 지경리 일대 해안단굴 지형발달)

  • 황상일;윤순옥;박한산
    • Journal of the Korean Geographical Society
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    • v.38 no.4
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    • pp.490-504
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    • 2003
  • The existence of coastal terraces, HH(High higher) surfaces found at Gampo of southeast coast and at Jeongdongjin of the central east coast were confirmed at Jjgyeong-Ri, the areal border between Gyeongjuand Ulsan city on the southeast coast of Korea Peninsula. Especially this study reports HH JK-surface located on the 155m a.s.l, which is the highest altitude among the ancient shorelines of the coastal terraces in Korea. The HH surfaces on the study area are classified into HH JK at 155m, HH I at 140m and HH II at 115m, and each formation stage is related to MIS 17(720∼690ka BP), MIS 15(630∼560ka BP) and MIS 13(510∼480ka BP) respectively. The HH-surfaces remain to be larger than those of H- and L-surfaces. The reason is caused by the unique factors of the coastal geology and morphology on the study area during the formation stage. And also the areal difference by the magnitude of upheaval doesn't exist from north to south because the altitude system of ancient shoreline on each coastal terrace is same along the east coast. The upheaval rate of the eastern coastal areas was measured in the relation to the ancient shoreline and formation stage among the coastal terraces such as HH JK-, HH I-, HH II, H I- and H II surface, and was almost same as 0.23mm/y.

A Geomorphology on the Ulleungdo (울릉도 지형지)

  • Kwon, Dong-Hi
    • Journal of The Geomorphological Association of Korea
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    • v.19 no.4
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    • pp.39-57
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    • 2012
  • The volcanic edifice of Ulleungdo is largely divided into a shield volcano underwater and a tholoide above seawater. The geological features of the volcano above seawater are basically alkali volcanic rocks that are further divided into five geological strata: agglomerates and tuffs trachyte and phonolite trachytic pumice trachyandesite, and sedimentary layer. The topography of Ulleungdo consists of volcanic landform on the whole, and such volcanic landform is weathered and eroded into various weathering landform, stream landform, coastal landform, structural landform, etc. Major volcanic topography includes caldera basin, central cone, and columnar joint, whereas weathering topography features, tafoni, gnamma, tor, weathered cave, talus, etc. In major coastal topography are sea cliff, wave-cut platform, sea stack, sea arch, sea cave, shingle beach, coastal terrace, etc. For stream topography, its development is minimal except for waterfalls.

The Characteristics and Genesis of Terrace Soils in Yeongnam Area -I. Macro-Morphological Features and Soil Profile Development Index of the Terrace Soils (영남지역(嶺南地域)에 분포(分布)된 단구지토양(段丘地土壤)의 특성(特性)과 생성연구(生成硏究) -제(第) 1 보(報) 단구지토양(段丘地土壤)의 형태적특성(形態的特性)과 토양단면발달도(土壤斷面發達度))

  • Jung, Y.T.;Um, K.T.;Ha, H.S.
    • Korean Journal of Soil Science and Fertilizer
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    • v.18 no.2
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    • pp.177-188
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    • 1985
  • To clarify the characteristics and genesis of clayey terrace soils in Yeongnam area, macro-morphological features and soil profile development indexes were investigated with the sequential soils in Yeongcheon (inland region) and in Yeongil (coastal region). The results are summarized as follows; 1. According to the physiogaphy and landuse, the terrace soils were discernible to well drained yellowish red (5 YR) profile of higher terrace (Bancheon series), moderately well drained reddish yellow (7.5 YR) profile of middle terraces (Upyeong and Hwadong series), and lower terraces (Deogpyeong and Geugrag series) which were moderately well to imperfectly drained by paddy-fication. 2. The roundness and sphericity of the gravels contained in the terrace deposits were ranged around 0.543-0.546 and 0.723-0.722, respectively. The rounded to well rounded gravels were resemble to typical alluvial origins. 3. The amount of clay minerals formed in the soil horizons per 100g of parent materials were 50.8-30.7g while the rates of the clay leached were 30.1-7.4%, and the higher terrace had the more leaching rates. 4. The index of profile development of the terrace soils ranged from 37.95 to 22.01 and the index were positively correlated with relative elevations of the soils. The rates of clay leaching were positively correlated with the ratios of clay in the illuvial horizons to elluvial horizons. 5. A similarity was observed among cumulative grain size curves of the terrace soils, but the patterns of recalculated silt free cumulative grain size curve of terrace deposits in Upyeong soils in Yeongil area were abruptly different from down layer that suggest the soil to have bisequum profile.

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The Ages of Fault Activities of the Ilgwang Fault in Southeastern Korea, Inferred by Classification of Geomorphic Surfaces and Trench Survery (지형면 분류 및 트렌치 조사에 의한 일광단층의 단층활동시기 추정)

  • Jang, Ho;Lee, Jin-Han;An, Yun-Seong;Joo, Byeong-Chan
    • The Korean Journal of Quaternary Research
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    • v.18 no.1 s.22
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    • pp.21-30
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    • 2004
  • The Ilgwang Fault is NNE-striking, elongated 40 Km between Ulsan and Haeundae-ku, Busan in southeastern part of the Korean Peninsula. This paper si mainly concerned about the ages of the fault activities especially in the Quaternary, inferred from classification of geomorphic surfaces and trench excavation for the construction of Singori nuclear power plant. The geomorphic surfaces are classified into Beach and the Alluvial plain, the 10 m a.s.l. Marine terrace(MIS 5a), the 20 m a.s.l. Marine terrace(MIS 5e), the Reworked surface of 45 m a.s.l. Marine terrace(MIS 7 or 9) and the Low relief erosional surface. The Low relief erosional surface is distributed coastal side, the Reworked surface of 45m a.s.l. Marine terrace inland side by the Ilgwang Fault Line as the boundary line. But the former is above 10 m higher in relative height than the latter. The 20 m a.s.l. Marine terrace on the elongation line of the Ilgwang Fault reveals no dislocation. A site was trenched on the straight contact line with $N30^{\circ}E$-striking between the 10 m a.s.l. Marine terrace and the 20 m a.s.l. Marine terrace. Fault line or dislocation was not observable in the trench excavation. Accordingly, the straight contact line is inferred as the ancient shore line of the 10 m a.s.l. Marine terrace. The Ages of the Fault activities are inferred after the formation of the Ichonri formation - before the formation of the 45 m a.s.l. Marine terrace(220 Ka. y. B.P. or 320. Ka. y. B.P.). The Low relief erosional surface was an island above the sea-level during the formation of the 45 m a.s.l. marine terrace in the paleogeography.

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Characteristics and depositional environment of paleosol layers developed on top of the terrace in the Jeongdongjin area, East Coast, Korea (강릉 정동진 지역 단구 고토양층의 특징과 퇴적 환경)

  • Yi, Seon-Bok;Lee, Yong-Il;Lim, Hyun-Soo
    • The Korean Journal of Quaternary Research
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    • v.23 no.1
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    • pp.1-24
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    • 2009
  • Paleosol layers lying on top of the terrace in Jeongdongjin area appear to have been deposited under generally well-drained condition with periodic waterlogging. From a 4.5m-long profile observed, a total of 6 stratigraphic units were identified. Grain-size analysis indicates the dominance of silty and clay materials with some portions with high sand content. Major mineralogical elements are quartz, feldspar, mica and chlorite. Geo-chemical composition shows little change throughout the stratigraphy with some fluctuation in chemical weathering index. Marked increase in magnetic susceptibility is recognizable where stratigraphic unit changes. Soil- wedge layer is developed around 50cm below the surface with concentration of grains of AT tephra (c. 25,000 BP). An OSL date of c. 110,000 BP was obtained from a sand layer lying below the paleosol.

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Mechanism of the Marine Terraces Formation on the Southeastern Coast in Korea (한국 남동해안 해안단구의 지형형성 mechanism)

  • 윤순옥;황상일
    • Journal of the Korean Geographical Society
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    • v.35 no.1
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    • pp.17-38
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    • 2000
  • The marine terraces often offer come important clues to understand the topographic development during the Quaternary and the present landforms in korea. We examined the mechanism of the marine terraces formation along the coast from Samjung-Ri(community), Guryongpo-Eup(county) to Haseo-Ri, Yangnam-Myun(county), Gyungju-Si(city). Among the various but unique factors of the given coastal environment, which should contribute to the marine terraces formation together, we focused on five possible factors for the present stydy. Geologic difference in bedrocks, protrusion degree of coastiline, topological relief of sea-bottom, fluvial characteristics on land, and pattern of the waves appeared to act cooperatibely on the terrace formation of Southeastem coast in korea, while the fluvial characteristics seemed play a significant but localized role in it. Wide distribution of middle surfaces on the coast of Samjungri-Janggilri could be due to the concentration of the high waves and the weakness of the Tertiary volcanic rocks. For the sporadic distribution of the terraces on the coast of Gupungri-Gyewonri, it seemed attributable to the erosion -susceptible weak bedrock, the coastline of inner bay, shallow sea-bottom with the gentle relief, and other fluvial characteristics with the low divides. Together with the geologic difference in bedrock, other factors including protrusion degree of coast, topological relief of sea-bottom, and the transportation loads by the stream Daejongchon are believed to act cooperatively on the mechanism of the marine terraces formation on the coast of Duwonri-Upchonri.

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Preservation and Utilitization of Uninhabited Islets in Busan Metropolitan City (부산광역시 해안 무인도서의 보전(保全)과 활용)

  • Kim, Hang-Muk;Yu, Je-U
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2009.06a
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    • pp.475-486
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    • 2009
  • The geological survey of the Mokdo island is for the fist time conduted in Korea history. The island had erupted before $70{\sim}80$ million years as a strato-volcano. The original volcano had been dissected for long periods up to the skeletal stage through the planeze stage. If the island area is surveyed afterwrds in detail, the position of crater is available to be found, either. The coastal terrace is found at 50m level in Mokdo island which is correlated to its fourth plane. The microgeomorphological features as coastal terrace, cliff, sea cave, wave-cut bench, sea stacks, notch, and tafoni, etc. were described. The Mogdo island is located off Molundae at the extension of Nagdong Jeongmaeg(낙동정맥 洛東正脈) showing a "floating turtle". The name of Mogdo island is needed to change to the "Yoo-goo-do" which means the swimming turtle. The Mokdo island is as suitable tourist attraction for if has enough touism sesouccesein sea. The deuelopsment of coartal sightseeing anound lighthoure and uninhabited islands will hare an impontant effect upon construction of the oceanic capitol city of Busan Haabor. The master plan built up an arboretum on the island, a coastal oceanarium, a seaweeds garden under sea coast, and other oceanic culture-spaces is completed in the study.

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Characteristics and Genesis of Terrace Soils in Yeongnam Area -III. Mineralogical Characteristics (영남지역(嶺南地域)에 분포(分布)된 단구지토양(段丘地土壤)의 특성(特性)과 생성(生成) 연구(硏究) -제(第)3보(報) : 광물학적(鑛物學的) 특성(特性))

  • Jung, Yeun-Tae;Um, Ki-Tae;Jung, Pil-Kyun;Ha, Ho-Sung
    • Korean Journal of Soil Science and Fertilizer
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    • v.19 no.2
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    • pp.89-97
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    • 1986
  • To clarify the soil characteristics and genesis of the clayey terrace soils in Yeongnam area, the study were carried out with 9 typifying pedons of toposequential terrace soils in Yeongcheon (inland area) and Yeongil (coastal area) region. The results of soil genesis oriented investigations on soil mineralogical compositions and weathering characteristics were summarized as follows; 1. The contents of heavy minerals contained in sand fraction of the terrace soils were less than 5%, but the content in soil layers considered to be originated from other than terrace deposits had 9.8-16.2%. The content of feldspars in light minerals were higher in Yeongcheon sequence while the Yeongil sequence were characterized by having higher content in quartz. The ratios of quartz/feldspars in the soil layers where expecting lithological discontinuity, were different from that of terrace deposits. 2. The resistate index of maturity ranged around 76.7-29.9 in Yeongcheon area and around 85.6-67.2 in Yeongil area. The indices increased with the elevations of terraces. 3. The molar ratios of $SiO_2/Al_2O_3$ in clay fraction were around 1.93-2.65. The parent materials of the terrace deposits judged by the ratios of $Al_2O_3/TiO_2$ and $Fe_2O_3/Al_2O_3$ were considered to be the felsic materials. 4. The compositions of clay minerals detected by X-ray diffractogram and D.T.A. thermogram were dominated by kaolin and illite with subsidiary minerals of vermiculite, quartz, vermiculite intergrading to illite etc. It was distinguished from terrace deposits that by having higher amount of kaolin and montmorin minerals in the substrata of Bancheon soils in Yeongcheon area and Upyeong soils in Yeongil area, respectively.

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Characteristics and Genesis of Terrace Soils in Yeongnam Area -V : Soil Genesis and Classification (영남지역(嶺南地域)에 분포(分布)된 단구지토양(段丘地土壤)의 특성(特性)과 생성연구(生成硏究) -제(第)5보(報) : 토양생성(土壤生成)과 분류(分類))

  • Jung, Yeun-Tae
    • Korean Journal of Soil Science and Fertilizer
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    • v.19 no.4
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    • pp.275-282
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    • 1986
  • A series of studies on the properties of clayey terrace soils distributed at the inland (Yeongcheon) and coastal (Yeongjil) regions in Yeongnam district was carried out. On the base of the facts found and already reported about the macro morphological features as well as on pedological characters in micro scale, physicochemical properties, mineralogical characteristics etc., the present study dealt with soil genesis and tried to classify the soils for reasonable use and managements. 1. Although the both regions belonged to "Mesic" soil temperature regime and "red and yellow earths" areas of "Thornthwaite" pedo-climatic diagram, climatic indices as a soil forming factor indicate that the coastal Yeongil had milder than the inland Yeongcheon. 2. All the terrace soils had developed soil profiles with an "Argrllic B". Upyeong soils in Yeongil region had "Argillans" even in the "II B horizons" that possibly be "Paleo-argillic". 3. The bisequum profiles of Bancheon in Yeongcheon and Upyeong in Yeongil revealed that they were developed on Late Mesozoic shale and on semiconsolidated Tertiary deposits respectively, therefore the overlying clayey terrace deposits were assumed to be originated from the Early Quaternary deposits, Diluvium. 4. To supplement the Soil Taxonomy of USDA, the terrace soils with different degrees of gleyzation were classified as follows; Deogpyeong and Hwadong soils which have less than 50cm of paddified gley horizons (redness less than 0.5) in the upper part of the profiles by artificial surface irrigation, tentatively classified into "Anthrepiaquic Hapludalfs" and the Geugrag soils that have more than 50cm of paddified gley horizons within 1.2m of the profiles, into "Anthr-aquic Ochraqualfs" while the Upyeong soils that had greyish mottles in subsoils by natural ground water remain as an "Aquic Hapludalfs" the same as present. The Bancheon soils with free mottles are into "Typic Hapludalfs" as used at present.

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