First finding of impact cratering in the Korean Peninsula

• Published in: Gondwana research 2021-03, Vol.91, p.121-128
• Main Authors: Lim, Jaesoo, Hong, Sei-Sun, Han, Min, Yi, Sangheon, Kim, Sung Won
• Format: Article
• Language: English
• Subjects: Impact breccia, Jeokjung–Chogye Basin, Korean Peninsula; Impact crater; Planar deformation features, PDFs; Shatter cone
• ISSN: 1342-937X; 1878-0571
• DOI: 10.1016/j.gr.2020.12.004

The 7 km-diameter Jeokjung–Chogye Basin in Hapcheon, southeastern Korean Peninsula, is well-known for its bowl-shaped geomorphology. Here we report the first direct evidence of impact cratering from this basin based our investigations on a 142 m-deep core. The lithological units could be divided into soil-channel sediments (0–6.2 m), lacustrine sediments with fine silt-clayey lamination (6.2–72 m), and impact breccia (72–142 m). We report for the first time, unique impact-driven metamorphic features, including shatter cones at 130 m and planar deformation features (PDFs) in quartz grains from the impact breccia. Based on the radiocarbon dates of charcoals in the lacustrine sediments, we estimate that the impact likely happened during the last glacial period, although further confirmation using other dating techniques is awaited. This relatively young crater provides a rare opportunity to reconstruct high-resolution paleoclimate changes recorded in laminated lacustrine sediments, and to investigate shock metamorphism in a location that experienced significant surficial weathering and erosion under a tropical–temperate climate. [Display omitted] •First report of robust evidence for impact cratering from Korean Peninsula•Shatter cones and PDF in quartz grains from a drilled core•Sedimentary records for impact-filling breccia and subsequent lacustrine sediments•Radiocarbon dates of charcoals constrain impact event at end of the late Pleistocene.•A rare archive of high-resolution paleoclimate changes in the East Asian continent.