• Title/Summary/Keyword: Quaternary landform

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Geomorphological Development and Fault Activity of the Central-Southern Yangsan Fault (I): Developmental Characteristics and Distribution of the Quaternary Landforms (양산단층 중남부 구간의 지형 발달과 단층 운동 (I): 제4기 지형의 발달 특성 및 분포)

  • Hong, Yeong-Min;Oh, Jeong-Sik;Hong, Seong-Chan;Shin, Jae-Ryul
    • Journal of The Geomorphological Association of Korea
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    • v.28 no.1
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    • pp.67-81
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    • 2021
  • Geomorphological development and distribution at the macro scale provide a clue to the geotectonic characteristics that have affected the geomorphological system. This is because the developmental characteristics and distribution of the landform at the macro scale remain spatial characteristics due to tectonic processes, such as fault activity. From the perspective of tectonic geomorphology, this study identified the developmental characteristics and distribution of the Quaternary landforms in central-southern Yangsan fault and discussed its relevance to fault activity. In this paper, we presented examples and results of morphotectonic analysis of the Yangsan fault, and will present the results of age dating, stratigraphic relationship of the Quaternary landforms, and calculation of cumulative slip rate in the next paper.

A geochemical study of karst landforms (Karst landforms의 지구화학적 연구)

  • 유재신
    • Journal of the Speleological Society of Korea
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    • v.24 no.25
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    • pp.1-14
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    • 1991
  • Jeongsun limestone formations with good geochemical solution of limestone and physical environments have been developing many Karst landforms. Especially, there are many dolines and most of them elliptical shapes of planes. At present, they have been transformed into uvala toward their long diameter directions. The period of landscape processing is a Quaternary Epoch and Karst cycle corresponds to a stage from late maturity to old stage.

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Volcanic landforms in Korea (한국의 화산지형 연구)

  • Kim, Taeho
    • Journal of The Geomorphological Association of Korea
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    • v.18 no.4
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    • pp.79-96
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    • 2011
  • Volcanic landforms are classified into the volcanic edifice produced through constructive processes of eruption and the crater generated by destructive processes of eruption. Both landforms are distributed around Korean Peninsula including attaching islands. However, only a few regions such as Mt. Baekdu, Jeju Island, Ulleung Island, and Chugaryeong, which are closely related with the volcanic eruption occurred during the Quaternary, could be considered as a volcanic landform. It results in categorizing the volcanic landform as an unusual topography in Korea. The study of Korean researchers on the volcanic landform were regularized in 1970s on Jeju Island, in 1980s on Ulleung Island, and in 1990s on Mt. Baekdu, respectively. Oreums and lava tubes in Jeju Island have been also examined since 1980s. Compared with other fields of geomorphology, researches as well as researchers on the volcanic landform are very few in Korea. Geomorphologists are expected to perform an active research in that the volcanic landform of Korea have diverse values.

Landform Changes of Terminal Area of the Nagdong River Delta, Korea (낙동강 삼각주 말단의 지형 변화)

  • 오건환
    • The Korean Journal of Quaternary Research
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    • v.13 no.1
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    • pp.67-78
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    • 1999
  • In present, the terminal area of the Nagdong River Delta consists of micro-depositional landforms with sand barrier islands, sand bars and tidal flats which are arranged parallel to the present shoreline, and have rapidly shifted toward sea during last 100 years due to human activities such as construction of estuary dam, industrial complex and residential area. To clarify the landform changes of the area, the author traced the morphologic change pattern based on interpretation of air-photos, topographic maps and old Korean traditional map, and the results are as follows ; Based on the Daedongyeojido, one of the old Korean map, published in 1861, the area including upper part of the delta was underlying by sea level except two larger sand barriers, which means the Nagdong River Delta was not completely formed as the present outline of morphology by 1860s. According to the topographic map(1 :50,000) of 1916, the delta resembled to the present morphology pattern was exposed in 1916, and at this time the area was mainly composed of one sand barrier island, four sand bars and tidal flats, which had slowly elongated southwards before construction of the Nagdong River Estuary Dam in 1987. But after 1987, the area has been rapidly and drastically shifted southwards in arrange with one chain of sand barrier islands (Elsugdo -Myeonghodo-Sinhodo ) and four chains of sand bars (first chain ; Jinwoodo -Daemadeung-Maenggeummeorideung, second chain : Jangjado-Baeghabdeung, third chain ; Saedeung-Namusitdeung, fourth : Doyodeung-Dadaedeung) parallel to shoreline. This rapid landform change of the area is now occurring, and is seemed to ascribed firstly, to the construction of the Nagdong River Estuary Dam on Elsugdo in 1987, the Sinho Industrial Complex on Sinhodo and Myeongji Residential Area on Myeonghodo in 1992, secondly, to artificial alteration of drainage channel and consequential breakdown of former energy system between riverflow and tidal-and wave-energy. From these facts, it is inferred that the landform change pattern of the area will continue until a new equilibrium between the factor available to this energy system is accomplished.

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A Theoretical Study on the Landscape Development by Different Erosion Resistance Using a 2d Numerical Landscape Evolution Model (침식저항도 차이에 따른 지형발달 및 지형인자에 대한 연구 - 2차원 수치지형발달모형을 이용하여 -)

  • Kim, Dong-Eun
    • Economic and Environmental Geology
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    • v.55 no.5
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    • pp.541-550
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    • 2022
  • A pre-existing landform is created by weathering and erosion along the bedrock fault and the weak zone. A neotectonic landform is formed by neotectonic movements such as earthquakes, volcanoes, and Quaternary faults. It is difficult to clearly distinguish the landform in the actual field because the influence of the tectonic activity in the Korean Peninsula is relatively small, and the magnitude of surface processes (e.g., erosion and weathering) is intense. Thus, to better understand the impact of tectonic activity and distinguish between pre-existing landforms and neotectonic landforms, it is necessary to understand the development process of pre-existing landforms depending on the bedrock characteristics. This study used a two-dimensional numerical landscape evolution model (LEM) to study the spatio-temporal development of landscape according to the different erodibility under the same factors of climate and the uplift rate. We used hill-slope indices (i.e., relief, mean elevation, and slope) and channels (i.e., longitudinal profile, normalized channel steepness index, and stream order) to distinguish the difference according to different bedrocks. As a result of the analysis, the terrain with high erosion potential shows low mean elevation, gentle slope, low stream order, and channel steepness index. However, the value of the landscape with low erosion potential differs from that with high erodibility. In addition, a knickpoint came out at the boundary of the bedrock. When researching the actual topography, the location around the border of difference in bedrock has only been considered a pre-existing factor. This study suggested that differences in bedrock and various topographic indices should be comprehensively considered to classify pre-existing and active tectonic topography.

Concepts and Geomorphic Properties on Fluvial Terraces (하안단구의 개념과 지형 특성)

  • Lee, Gwang-Ryul
    • The Korean Journal of Quaternary Research
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    • v.25 no.1
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    • pp.1-13
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    • 2011
  • To reinterpret the meaning of fluvial terraces in the Quaternary researches, the concepts and geomorphic properties of fluvial terraces are reviewed. Fluvial terraces are the alluvial landform that was once river channel or floodplain by paleochannel flowed in elevated areas from the current river by active incision of rivers due to the climatic changes and/or uplifts. As fluvial terraces are the remnants of alluviums after incisions of rivers, the major factors influencing on the incisions are the falling of erosion base, increase of river discharge and distinct geomorphic phenomenon of river. While it is generally known that fluvial terraces deposits in the upper or middle reaches of large rivers were formed during glacial periods, the deposits may be formed at the various periods due to the diverse natural environments and geomorphic properties of specific rivers, because there have been numerous cases that the ages of fluvial terraces in the upper or middle reaches of large rivers in Korea and China can be correlated to the interglacial periods.

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The Type of Dwelling Sites of Ancient People and Excavation-Recommended Spot in the Viewpoint of Geomorphology - 'Ohnju Region Urban Development Business Site' as an Example - (지형학적 관점에서 본 고대인의 생활터전 유형 및 시굴 추천지점 -충남 아산 '온주지구 도시개발 사업부지'를 사례로-)

  • Park, Ji-Hoon
    • The Korean Journal of Quaternary Research
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    • v.25 no.2
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    • pp.25-37
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    • 2011
  • The purpose of this study is to assume the particular area of hills where it is highly possible for historical site to be buried in the viewpoint of geomorphology and based on this to suggest excavation-recommended area. Namely, this writer is to understand the dwelling site type of ancient people who had resided there at that time for the object of 'Ohnju region urban development business site' (referred as investigation area hereinafter) and considering the characteristics of micro-landform of hills which are distributed in investigation area and is to recommend the area where it is highly possible for historical site to be buried. The result of analysis is like the following. (1) Dwelling site types of ancient people who might have resided in the whole area of investigation region are discovered to be largely 'low hills+wetland' of Type-I and 'alluvial fan(or river terrace+wetland' of Type-II. (2) In investigation area if the area which has high possibility of distribution of historical site namely, excavation-recommended area is looked as based on micro-landform unit of hills, they are Crest slope and Crest flat. Individual area ratios which Crest slope and Crest flat occupies in investigation area are 12.9% and 10.2% respectively and the rankings are 3 and 6 each. And excavation-recommended areas in valley plain(or bottomland) of investigation area are in the vicinity of 'distal end' or 'buried distal end'of small scale alluvial fan.

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한강하류지형면의 분류와 지형발달에 대한 연구 (양수리에서 능곡까지)

  • Park, No-Sik
    • Journal of the Speleological Society of Korea
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    • no.68
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    • pp.23-73
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    • 2005
  • Purpose of study; The purpose of this study is specifically classified as two parts. The one is to attempt the chronological annals of Quaternary topographic surface through the study over the formation process of alluvial surfaces in our country, setting forth the alluvial surfaces lower-parts of Han River area, as the basic deposit, and comparing it to the marginal landform surfaces. The other is to attempt the classification of micro morphology based on the and condition premising the land use as a link for the regional development in the lower-parts of Han river area. Reasons why selected the Lower-parts of Han river area as study objects: 1. The change of river course in this area is very serve both in vertical and horizontal sides. With a situation it is very easy to know about the old geography related to the formation process of topography. 2. The component materials of gravel, sand, silt and clay are deposited in this area. Making it the available data, it is possible to consider about not oかy the formation process of topography but alsoon the development history to some extent. 3. The earthen vessel, a fossil shell fish, bone, cnarcoal and sea-weed are included in the alluvial deposition in this area. These can be also valuable data related to the chronological annals. 4. The bottom set conglometate beds is also included in the alluvial deposits. This can be also valuable data related to the research of geomorphological development. 5. Around of this area the medium landform surface, lower landform surface, pediment and basin, are existed, and these enable the comparison between the erosion surfaces and the alluvial surfaces. Approach : 1. Referring to the change of river beds, I have calculated the vertical and horizontal differences comparing the topographic map published in 1916 with that published in 1966 and through the field work 2. In classifying the landform, I have applied the method of micro morphological classification in accordance with the synthetic index based upon the land conditions, and furthermore used the classification method comparing the topographic map published in 1916 and in that of 1966. 3. I have accorded this classification with the classification by mapping through appliying the method of classification in the development history for the field work making the component materials as the available data. 4. I have used the component materials, which were picked up form the outcrop of 10 places and bored at 5 places, as the available data. 5. I have referred to Hydrological survey data of the ministry of Construction (since 1916) on the overflow of Han-river, and used geologic map of Seoul metropolitan area. Survey Data, and general map published in 1916 by the Japanese Army Survbey Dept., and map published in 1966 by the Construction Research Laboratory and ROK Army Survey Dept., respectively. Conclusion: 1. Classification of Morphology: I have added the historical consideration for development, making the component materials and fossil as the data, to the typical consideration in accordance with the map of summit level, reliefe and slope distribution. In connection with the erosion surface, I have divided into three classification such as high, medium and low-,level landform surfaces which were classified as high and low level landform surfaces in past. furthermore I have divided the low level landform surface two parts, namely upper-parts(200-300m) and bellow-parts(${\pm}100m$). Accordingly, we can recognize the three-parts of erosion surface including the medium level landform surface (500-600m) in this area. (see table 22). In condition with the alluvial surfaces I have classified as two landform surfaces (old and new) which was regarded as one face in past. Meamwhile, under the premise of land use, the synthetic, micro morphological classification based upon the land condition is as per the draw No. 19-1. This is the quite new method of classification which was at first attempted in this country. 2. I have learned that the change of river was most severe at seeing the river meandering rate from Dangjung-ni to Nanjido. As you seee the table and the vertical and horizontal change of river beds is justly proportionable to the river meandering rate. 3. It can be learned at seeing the analysis of component materials of alluvial deposits that the component from each other by areas, however, in the deposits relationship upper stream, and between upper parts and below parts I couldn't always find out the regular ones. 4. Having earthern vessel, shell bone, fossil charcoal and and seaweeds includen in the component materials such as gravel, clay, sand and silt in Dukso and Songpa deposits area. I have become to attempt the compilation of chronicle as yon see in the table 22. 5. In according to hearing of basemen excavation, the bottom set conglomerate beds of Dukso beds of Dukso-beds is 7m and Songpa-beds is 10m. In according to information of dredger it is approx. 20m in the down stream. 6. Making these two beds as the standard beds, I have compared it to other beds. 7 The coarse sand beds which is covering the clay-beds of Dukso-beds and Nanjidobeds is shown the existence of so-called erosion period which formed the gap among the alluvial deposits of stratum. The former has been proved by the sorting, bedding and roundness which was supplied by the main stream and later by the branch stream, respectively. 8. If the clay-beds of Dukeo-bed and Songpa-bed is called as being transgressive overlap, by the Eustatic movement after glacial age, the bottom set conglomerate beds shall be called as being regressive overlap at the holocene. This has the closest relationship with the basin formation movement of Seoul besides the Eustatic movement. 9. The silt-beds which is the main component of deposits of flood plain, is regarded as being deposited at the Holocene in the comb ceramic and plain pottery ages. This has the closest relationship with the change of river course and river beds.

Distribution of Fault-related Landforms and Lineaments Along the Ulsan Fault Zone (울산단층대 주변의 단층 지형 및 선구조 분포)

  • Lee, Gwang-Ryul;Park, Chung-Sun;Shin, Jae-Ryul
    • Journal of The Geomorphological Association of Korea
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    • v.25 no.3
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    • pp.89-103
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    • 2018
  • This study presents results of analysis on fault-related landforms and the Quaternary fluvial landforms, which are important evidences for active faulting by identifying surface deformation, around the Ulsan Fault Zone. In addition, this study suggests lineament map and inferred active fault-line map based on analyzing linearity and continuity of these landforms and by compiling location information of existing active faults. We convince that quantitative tectonic-geomorphological analysis are an effective method for active faults tracking, in particular, considering the conditions of relatively low seismicity and surface ruptured-events in the Korean Peninsula compared to plate boundary active areas. However, research on active fault in South Korea is just an infant stage since the 1990s and requires accumulation of research achievements on development and application of various fault analysis techniques, analysing and standardizing linear structures.