Coastal landscape evolution tracked from late Holocene wave-cut benches in the Sinan Archipelago,Southwest Korea  

作　　者：Sung-Ja Choi Bokchul Kim Yong Sik Gihm Sanghoon Kwon 

机构地区：[1]Geology Division,Korea Institute of Geoscience and Mineral Resources,Daejeon,34132,Republic of Korea [2]Department of Earth System Sciences,Yonsei University,Seoul,03722,Republic of Korea [3]School of Earth Sciences,The Ohio State University,Columbus,OH,43210,USA

出　　处：《Geoscience Frontiers》2020年第1期293-301,共9页地学前缘（英文版）

基　　金：supported by grant 2017-MOIS31-006 from the Research and Development of Active Faults of Korea Peninsula funded by the Korean Ministry of Public Safety and Security (MPSS);by grant NP2018-017 from the Research on Geologic Hazard Assessment of Large Fault Systems Focusing on the Central Region of the Yangsan from the Basic Research Project of the Korea Institute of Geoscience;Mineral Resources (KIGAM) funded by the Korean Ministry of Science and ICT.S.K.appreciate the partialsupport by the NRF-2017R1A6AIA07015374 (Multi-disciplinary study for assessment of large earthquake potentials in the Korean Peninsula);NRF-2019R1A2C1002211 through the National Research Foundation of Korea funded by the Ministry of Science and ICT,Korea

摘　　要：Glacio-isostatic adjustment(GIA)and tectonic activity are important factors in the formation of marine terraces.Late Holocene wave-cut benches in the eastern part of the West Sea of Korea,also called the Yellow Sea,can be divided into two steps:531 cm above sea level(ASL)for the upper bench(T2)and 464-481 cm ASL for the lower bench(T1).Sediments on the benches a re classified into four units,and are interpreted to be beach deposits acco rding to gravel shape,textu re,and seaward inclination.The ove rlying sediment indicates that T2 was formed at approximately 530 cm ASL before 2900 yr BP,and T1 at approximately 460-480 cm ASL before 1520 yr BP.Late Holocene(4000-2000 yr BP)relative sea level(RSL)curves based on GIA models are inconsistent with the wave-cut bench elevations.Comparing T1 and T2 benches to the RSL curves of the West Sea,the upper and the lower benches were uplifted by approximately 5-8 m and 4-7 m,respectively.Although the area is several hundred kilometers away from plate boundaries,the high frequency of earthquakes in the West Sea may have induced the uplift of wave-cut benches during the last 2000 years.These indicate that the west coast of the Korean Peninsula(KP)should no longer be considered an area of subsidence,but be assigned to a regime of uplift during the late Holocene.Glacio-isostatic adjustment(GIA) and tectonic activity are important factors in the formation of marine terraces.Late Holocene wave-cut benches in the eastern part of the West Sea of Korea,also called the Yellow Sea,can be divided into two steps:531 cm above sea level(ASL) for the upper bench(T2) and 464-481 cm ASL for the lower bench(T1).Sediments on the benches a re classified into four units,and are interpreted to be beach deposits acco rding to gravel shape,textu re,and seaward inclination.The ove rlying sediment indicates that T2 was formed at approximately 530 cm ASL before 2900 yr BP,and T1 at approximately 460-480 cm ASL before 1520 yr BP.Late Holocene(4000-2000 yr BP) relative sea level(RSL) curves based on GIA models are inconsistent with the wave-cut bench elevations.Comparing T1 and T2 benches to the RSL curves of the West Sea,the upper and the lower benches were uplifted by approximately 5-8 m and 4-7 m,respectively.Although the area is several hundred kilometers away from plate boundaries,the high frequency of earthquakes in the West Sea may have induced the uplift of wave-cut benches during the last 2000 years.These indicate that the west coast of the Korean Peninsula(KP) should no longer be considered an area of subsidence,but be assigned to a regime of uplift during the late Holocene.

关 键 词：West Sea of Korea Yellow Sea Late Holocene Wave-cut benches Beach sediment UPLIFT TECTONICS 

分 类 号：P534.63[天文地球—第四纪地质学] P736.22[天文地球—古生物学与地层学] P738[天文地球—地质学]