• Korean Journal of Mineralogy and Petrology
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• v.33 no.4
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• pp.349-359
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• 2020

The Ulsan Fault Zone (UFZ) of NNW trend is developed in the Gyeongsang Basin, the southeastern part of the Korean Peninsula, and the Quaternary faults have been found around the UFZ. The faults generally thrust the Bulguksa igneous rocks of Late Cretaceous-Early Tertiary upon the Quaternary deposits or are developed within the Quaternary deposits. They mainly show the reverse-slip sense of top-to-the west movement. The lines connecting the their outcrop sites show a zigzag-form which is similar to the orientation of their fault surfaces which show the various trends, like (W)NW, N-S, (E)NE, ENE trends. The E-W trending dextral strike(-slip) fault is found in the Quaternary deposits of the Singye-ri valley. It cuts the N-S trending reverse fault and are cut by the N-S trending thrust fault again. Two types of at least two times of Quaternary tectonic movements related to the formation of neotectonic fault zone in the Singye-ri valley are considered from such the geometric and kinematic characteristics of Quaternary faults. One is the reverse faulting of N-S trend by the E-W directed 1st compression and associated the strike-slip tear faulting of E-W trend, and then the thrust faulting of N-S trend by the E-W directed 2nd compression. The other is the reverse faulting of N-S trend, and then the dextral strike-slip faulting of E-W trend by the NW-SE directed compression, and then the thrust faulting of N-S trend. In this paper is suggested the development history of Singye-ri neotectonic fault zone on the basis of the various orientations of Quaternary fault surfaces around the UFZ, and the zigzag-form connecting line of their outcrop sites, and the compressive arc-shaped lineaments which convex to the west reported recently in the Yangsan Fault Zone.

• The Korean Journal of Quaternary Research
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• v.13 no.1
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• pp.79-89
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• 1999

Three deep borings to obtain vertical continuous samples including weathered basement soils (KP-1, KP-2 and KP-3) were carried out in the reclaimed Kimpo tidal flat with purposes to establish late Quaternary stratigraphy. On the basis of detailed observations and descriptions on color, sedimentary structure and textural composition of cored sediments, four lithostratigraphic units are classified. From the stratigraphic top to bottom, they are Holocene tidal sand and muddy deposit (Unit I), early Holocene freshwater marsh muddy deposit (Unit II), late Pleistocene tidal sand and muddy deposit (Unit III) and late Pleistocene basal fluvial gravel deposit (Unit IV). In particular, Unit III is divided into two parts: the upper part-weathered and cryoturbated part during the Last Glacial Maximum (Unit III-a) and the lower part-unweathered tidal sand and muddy deposit (Unit III-b).

• The Korean Journal of Quaternary Research
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• v.11 no.1
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• pp.25-38
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• 1997

한국서남해안에 위치한 해남만의 조수 퇴적층(체)에 관한 층서 설정이 제4기후기 (late Quaternary)의 시간범위로 가능하였다. 즉 현재의 해남만에 분포하고 있는 조간대층은 지난 중기와 후기 현세(middle to late Holocene)동안에 형성된 퇴적지층단위(depositional sequence unit)이며 이 지층단위는 선현세(late Pleistocene)조간대 퇴적지층단위 disconformity 의 부정합 관계로 피복하고 있다 본연구에서는 전자를 Unit I(8-10m 내외의 두께)이라 칭하고 후자를 Unit II(10m 내외의 두께)라고 구분 명명하였다, 그런데 Unit II는 암상(lithofacies)의 특징에 근거하여 상부(upper part)와 하부(lower part)로 나누어진다. 상 부는 약 3-4m 의 두께를 가지고 있으며 황갈색을 분명히 나타내며 게 구멍 화석과 동토구 조(cryogenic structure)그리고 매우 높은 값의 전단응력을 나타낸다, 그러나 하부는 회색을 띄며 낮은 전단응력 값을 나타내 상부와 뚜렷이 구분된다 이러한 Unit II의 상부가 나타내 는 암상적 특징은 지난 간빙하기(Eemian interglacial time)에 형성된 오늘과 같은 조간대층 이 18,000년 전후의 최대 빙하기(last glacial maximum : LGM) 동안의 지배하에 노출되었 고 오랜동안 토양형성 과정이 풍화작용을 받은 증거를 나타내고 있다, 따라서 이지층의 층 서학적 단위 설정과 부정합 (disconformity) 적인 경계의미는 우리나라 제4기 층서(late Quaternary stratigraphy)를 규정하는데 매우 중요하다고 제안하는 바이다.

• 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.

• Ocean and Polar Research
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• v.25 no.4
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• pp.557-567
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• 2003

High-resolution (3.5 kHz) subbottom profiles were analyzed in order to reveal sedimentation pattern of late Quaternary in the northern South Shetland continental margin and the South Scotia Sea, Antarctica. On the basis of clarity, continuity and geometry of surface and subbottom echoes together with seafloor topography, high-resolution echo characters are classified into eight echo types which represent rock basements (echo type III-1), coarse-grained subglacial till or moraine (echo type I-1), slides/slumps (echo type IV), debris-flow deposits (echo types II-3 and III-2), and bottom-current deposits (echo types I-2, II-1 and II-2). Subglacial till or moraine (echo type I-1) is mostly present in the lower continental shelf and upper continental slope of the northern South Shetland continental margin, which changes downslope to slides/slumps (echo type IV) and debris-flow deposits (echo types II-3 and III-2) in the middle to lower continental slope. This distribution suggests that the continental slopes of the northern South Shetland continental margin were mostly affected by downslope gravitational processes. Further downslope, bottom-current sediments (echo type I-2) deposited by the southwestward flowing Antarctic Deep Water (ADW) occur at the South Shetland Trench, reflecting an Interaction between mass flows and bottom currents in the area. In contrast to the northern South Shetland continental margin, the South Scotia Sea is dominated by bottom-current deposits (echo types II-1 and II-2), indicating that the sedimentation was mostly controlled by the westward flowing ADW. Flow intensity of the ADW has increased in the relative topographic highs, forming thin covers of coarse-grained contourites (echo type II-1), whereas it has decreased in the relative topographic lows, depositing thick, fine-grained contourites (echo type II-2). The poor development of wave geometry in the fine-grained bottom-current deposits (echo type II-2) is suggestive of the unsteady nature of the ADW flow.

• Journal of the Korean earth science society
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• v.42 no.1
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• pp.55-64
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• 2021

Tephrochronology is the study of tephra layers to correlate and date geologic events. As tephra layers can be used as time-markers, they are essential for the dating of Quaternary deposits. In this study, two types of tephra layers were found in the upper and lower parts of marine terrace deposits distributed in the Sanha-dong and Jeongja-dong, Ulsan areas. Based on the morphological features of glass shards, refractive indices, major element compositions, and similarity coefficients, the upper and lower tephras were identified as AT (ca. 25 ka) and Ata (ca. 105-110 ka) tephra, respectively. To the best of our knowledge, this is the first official report of Ata tephra on terrestrial deposits in Korea. These results are expected to aidin the research of the Quaternary paleoclimate, paleoenvironment, and active faults in the southeastern part of Korea.

• The Korean Journal of Quaternary Research
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• v.19 no.1
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• pp.1-17
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• 2005

This study aims to study the distribution and formation age of Quaternary deposits in the downstream of Yeongsan Estuarine River, encompassing Muan, Illo and Donggang counties. For this purpose the authors examine several borehole data, and step trench survey for excellent profiles was studied in connection with grain size population and magnetic susceptibility. As a result, it is interpreted that the coastal plain of the Yeongsan River was formed by sea level rise after Last Glacial Maximum(LGM). The fore edge/escarpment of coastal terraces distributed 7-10 m asl is assumed to be formed during the last glacial period, while the coastal terraces distributed above 7-10m asl formed during MIS 5a. In addition, the fore edge/escarpment of coastal terraces distributed above 15 m asl is presumed to be have been formed during the stadial of last interglacial period, while the formation age of coastal terraces distributed above 15m(asl) is assumed to be MIS 5e. This formation age can be estimated by the coastal terrace ages of the southeastern coast of Korean Peninsula. The characteristics of Quaternary deposits linked to paleolithic culture will eventually lead to the reconstruction of ecosystem environment of paleolithic peoples.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.2 no.2
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• pp.138-150
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• 1997

The late Quaternary stratigraphy of the tidal deposits in the Hampyung Bay, southwestern coast of Korea comprises 1) Unit III (nonmarine fluvial coarse-grained sediments), 2) Unit II (late Pleistocene tidal deposits), and 3) Unit I (late Holocene fine-grained tidal deposits) in ascending order. The basements of the Hampyung Bay is composed of granitic rocks and basic dyke rocks. These three units are of unconformally bounded sedimentary sequences. The sequence boundary between Unit I and Unit II, in particular, seems to be significant suggesting erosional surface and exposed to the air under the cold climate during the LGM. The uppermost stratigraphic sequence (Unit I) is a common tidal deposit formed under the transgression to highstand sea-level during the middle to late Holocene.

• The Korean Journal of Quaternary Research
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• v.12 no.1
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• pp.99-109
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• 1998

유성구 장대동 지역의 홀로세 하성퇴적층에서 보존 상태가 양호한 화분, 포자가 풍 부하게 산출되었다. 이들 미화석산출을 근거로하여 두 개의 화부대가 설정되었다. 제 I 화분 대는 낙엽성활엽수의 목본화분이 풍부하게 산출괴며 반면에 초본화분은 상대적으로 빈약한 상태로 산출되는 것이 특징이다. 제 II화분대는 초본화분 중 벼과(재배종)화분이 우점으로 산출되며 소나무속도 비교적 풍부하게 산출되는 반면 낙엽성활엽수의 목본화분은 빈약하게 산출되는 것이 특징이다. 시대설정은 인접한 지역에서 화분분석과 함께 절대연령측정이 수 행된 기존의 연구자료와 비교하여 이루어졌다. 따라서 제 I화분대는 1,500 year B.P 이전 제 II화분대는 1,500 year B.P∼현재를 나타낸다. 제 I화분대에서는 인간간섭의 영향을 받기 전 인 자연식생관계를 나타내지만 제 II화분대에서는 농경과 벌목이 본격적으로 시작된 시기로 나타났다, 기후조건은 제 I화분대 동안은 온난한 온대의 습한 환경이었고, 제 Ii화분대 동안 은 현재와 비슷한 한랭한 온대의 습한 환경이었던 것으로 판단된다, 인간의 정착과 농경생 활의 시기에 대한 해석에 있어서 화분분석자료와 고고학자료가 서로 잘 일치하는 것으로 본 연구에서는 나타났다.

• The Korean Journal of Quaternary Research
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• v.18 no.2 s.23
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• pp.17-17
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• 2004

The Pleistocene lake level and climate development is described by proxies from sediment, pollen and diatom records in Mongolia and Northwest-China. It could be proved that higher lake levels seem to have existed during the old and mid Pleistocene period interpreted on the base of geomorphological and sedimentological reords. They are dated in a relativ time scale. The lake basins are filled up to 300 m by limnic deposits, which foused on a constant water balance of more than 700.000 years. Late Glacial and Holocene lake level fluctuations and climate changes can be proved by biostratigraphic records pointing to dry and wet phases. Only for the youngest history desiccation of some lakes are related to human impact.