Jeokjung-Chogye Basin - Hypervelocity Impact Crater

Alternate Names N/A
Coordinates 35° 32' 60" N; 128° 16' 12" E
Notes
  1. SE Korean Peninsula near the middle reach on the west side of the Nakdong River.
Country South Korea
Region Gyeongsangnam-do
Date Confirmed 2021
Notes
  1. Confirmed by shatter cones and PDFs in quartz grains from impact breccia (Lim et al., 2021).
Buried? No
Notes
  1. Crater interior is filled by ~100 m of lacustrine sediments (Lim et al., 2021).
Drilled? Yes
Notes
  1. One borehole (CR05) was drilled to a depth of 142 m, located within the crater (Lim et al, 2021).
Target Type Sedimentary
Notes
  1. Study area dominantly composed of Dongmyeong (DMF), Chilgog (CGF), and Silla (SCF) conglomerate formations which are Cretaceous and Mesozoic formations (Lim et al., 2021).
Sub-Type Conglomerate, Limestone, Sandstone, Shale
Apparent Crater Diameter (km) Unknown
Age (Ma) 0.030 - 0.063
Notes :
  1. Impact event likely occurred during the last glacial period at the end of the late Pleistocene with a maximum age of 63,000 years and minimum age of 30,000 years based on radiocarbon dating and rates of sedimentation (Lim et al., 2021).

Method :
  1. Radiocarbon
Impactor Type Unknown

Advanced Data Fields

Notes

Local Language
N/A
Erosion
3
  1. The tropical-temperate climate has caused significant surface weathering and erosion. No ejecta deposits reported. Crater-fill deposits preserved below lacustrine sediments.
Final Rim Diameter
8 km
Apparent Rim Diameter
Unknown
  1. The ring-like depression measures 6-8 km in diameter from rim to rim (Lim et al., 2021).
Rim Reliability Index
2
  1. Central uplift parameters are currently not constrained as central area of crater is beneath lacustrine sediments.
Crater Morphology
Complex
Central Uplift Diameter
Unknown
Central Uplift Height
Unknown
Uplift Reliability Index
Unknown
Structural Uplift
Unknown
Thickness of Seds
Unknown
Target Age
Mesozoic
Marine
No
Impactor Type
Unknown
Other Shock Metamorphism
Kink bands
  1. Mica is common among rocks in the basin and muscovite grains in breccia show kink bands (Lim et al., 2021).
Shatter Cones
Yes
  1. Shatter cones were found in a shale clast at a depth of 130 m in the drill core (Lim et al., 2021).
Planar Fractures
No
Planar Deformation Features
Yes
  1. Quartz grains from impact breccia collected at depth of 86 and 142 m contain clear decorated PDFs (Lim et al., 2021).
Diaplectic Glass
No
Coesite
No
Stisovite
No
Crater Fill
LB
  1. Crater-fill breccia is at least 70 m thick based on one drill core (Lim et al., 2021). No melt reported yet, based on this single drill core.
Proximal Ejecta
Unknown
Distal Ejecta
Unknown
Dykes
Unknown
Volume of Melt
Unknown
Depth of Melting
Unknown

References

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Jaesoo Lim, Sei-Sun Hong, Min Han, Sangheon Yi, Sung Won Kim (2021) First finding of impact cratering in the Korean Peninsula, Gondwana Research 91, p. 121-128, url, doi:https://doi.org/10.1016/j.gr.2020.12.004