• Title/Summary/Keyword: Pleistocene지반운동

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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.

Marine terrace and its implications to paleoenvironment during the Quaternary at Suje-ri - Suryum-ri of the East coast of Gyeongju, SE Korea (한반도 남동부 경주시 수제리-수렴리의 해안단구와 제4기 환경변화)

  • HWANG, Sangill;SHIN, Jaeryul;YOON, Soon-Ock
    • Journal of The Geomorphological Association of Korea
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    • v.19 no.3
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    • pp.97-108
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    • 2012
  • During the last few decades, the ever-increasing knowledge of coastal morphogenic processes has made marine terraces the most recognizable, widespread and scientifically reliable records to determine both qualitatively and quantitatively the vertical movements that have affected the tectonically active coastal regions during the Quaternary. This study first aims to address the marine terrace records from Suje-ri to Suryum-ri along the coast of Gyeongju, SE Korea. Eight distinct flights of terraces, including HH YC, elevated up to 160 m above present sea level have been mapped along the coast of the study areas, and are designated $L_{II}$ to HH YC from the youngest to oldest. Based on the elevation of paleo-shoreline and inferred formation age for HH YC uplift rate since the middle Pleistocene has been estimated at 0.23 mm/year. Establishing the nature and timing of the uplift history derived from marine terraces provide a better understanding of neotectonic framework for explain enigmatic, complex landscape evolution in the Korean peninsula.

Absolute Age Determination of One of the Oldest Quaternary(?) Glacial Deposit (Bunthang Sequence) in the Tibetan Plateau Using Radioactive Decay of Cosmogonic $^{10}Be$ and $^{26}Al$, the Central Kavakoram, Pakistan: Implication for Paleoenvironment and Tectonics (방사성 우주기원 동위원소를 이용한 티벳고원에서 가장 오래된 제4기(?) 빙성퇴적물인 Bunthang sequence의 절대 연대측정과 이의 고환경 및 지반운동에 대한 의미)

  • Seong, Yeong-Bae
    • Journal of the Korean Geographical Society
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    • v.42 no.2 s.119
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    • pp.165-176
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    • 2007
  • Absolute age of the deposition of 1.3 km-thick Bunthang sequence within the Skardu intermontane basin of the Central Karakoram was determined using radioactive decay of cosmogonic $^{10}Be$ and $^{26}Al$ burial dating. The Bunthang sequence deposited around 2.65 Ma, which is the oldest glaciation in the region. The timing of deposition of the Bunthang sequence is consistent with the previous suggestion that the basin filling took place between Brunhess and Matuyama chrons. Four major sedimentary facies interfinger within the Bunthang sequence: glacial diamict, lacustrine, fluvial and lacustrine facies upward. This sedimentary distinctiveness and the lack of evidence on the faults for alternative pull-apart basin model around the Bunthang sequence, suggest that the depressional basin was formed by deep subglacial erosion during the exrtensive Bunthang Glacial Stage and subsequently the sediments underlain by basal diamict, was quickly deposited by preglacial and paraglacial processes. Temporary ponding of the Indus River due to tectonic uplift in the downstream or blockage by mass movements might make the basin filing more possible. The hypothesis that the single ice sheet developed on the Tibetan Plateau during the global last glacial cycle should be refuted by the existence of the older extensive Bunthang glacier Furthermore, the extensive glaciation during the early Quaternary (and thus progressive decrease in extent with time) suggests that there may have been significant uplift of the Pamir to the west and Himalaya to the south, which would have reduced the penetration of westerlies and Indian summer monsoon and hence moisture supply to the region.