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The Formative Processes and Ages of Paleo-coastal Sediments in Dangjeong-ri, Seocheon-gun in the Western Coast, South Korea: Evaluation of the Mode and Strain Rate of the Late Quaternary Tectonism (III)

서해안 서천군 당정리 일대에 분포하는 육상 고해안 퇴적물의 형성 과정과 형성 시기: 한반도 제4기 후기 지각운동의 양식과 변형률 산출을 위한 연구(III)

  • Shin, Jae-Ryul (Department of Geography Education and Engineering Research Institute, Gyeongsang National University) ;
  • Hong, Yeong-Min (Department of Geography Education, Gyeongsang National University) ;
  • Hong, Seongchan (Department of Geography Education, Korea National University of Education)
  • 신재열 (경상대학교 지리교육과 및 공학연구원) ;
  • 홍영민 (경상대학교 지리교육과) ;
  • 홍성찬 (한국교원대학교 지리교육과)
  • Received : 2020.02.27
  • Accepted : 2020.03.23
  • Published : 2020.03.30

Abstract

A number of unconsolidated deposits, consisting of a layer of gravels and silt, are found in Dangjeong-ri, Seocheon-gun in the western coast. From below in the stratigraphic sequence, the gravel layer ranging up to a maximum thickness of about 2 meters is interpreted as being formed by fluvial processes of an old channel (Dangjeong S.), and the overlying silt or sandy silt layer of 2 to 3 thickness meters is assumed to be emerged paleo-tidal sediments which was deposited in low tidal-energy environments. As the results of rock surface IRSL datings, the depositional ages of gravels are confirmed as ca. 78,000 ~ 83,000 years BP, indicating that the layer was formed in response to a high-stand sea level of MIS 5a along the Dangjeongcheon estuary. It is presumed that the relative height of 4.5 meter between the altitude of the stream bed (9.5 m) and the altitude of the bedrock boundary in the gravel layer (14 m) indicates the uplift amount since deposition. Paleo-sedimentary environments and an altitude of paleo-shoreline in the study area will be discussed with additional age dating focused on the silt layer.

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Acknowledgement

이 논문은 2017년 대한민국 교육부와 한국연구재단의 지원을 받아 수행된 연구입니다(NRF-2017S1A5A8020747).