The Sanbukdong Formation () is a Lower Cretaceous geologic formation in South Korea. It has been dated to the Aptian-Albian stage.
The lithology of the Sanbukdong Formation consists mostly of dark-grey mudstone, with occasional reddish mudstone and sandstone. Sedimentary structures, including ripple marks and cracks are often found. The age of the Sanbukdong Formation was initially suggested as Early Cretaceous based on plant fossil records, but Jeong et al. 2023 presented a more detailed age of this formation as 112.5±5.8 Ma based on detrital zircons, which spans from Aptian to lower Albian.
A large dinosaur tracksite is known from the formation, a total of 425 tracks including 14 trackways from 3 horizons, made by ornithopod and theropod trackmakers. The tracksite was designated as Natural Monument of Korea in 2014, entitled <Tracksite of Dinosaurs and Pterosaurs in Sanbuk-dong, Gunsan>.
Fossil content spinicaudatans and invertebrate traces are known from this formation.
Icnhnofossils
Genus Species Location Stratigraphic positionMaterialNotesImagesCaririchniumSanbukdong tracksiteTrackways, divided into four groups based on size. The largest footprint is 51cm in length.Entire morphology very similar to C. lotus. Ichnomorphological features suggested all tracks have been made by the same kind of trackmakers. TheropodaSanbukdong tracksiteTrackways, the largest footprint over 40 cm in length.Entire morphology resembles Irenesauripus mclearni and I. glenrosensis. Attributable to Carcharodontosauridae trackmaker.PterosauriaSanbukdong tracksiteTracksNot described formallyKoreanaornisK. ?dodsoni K. sp.UnknownTracksContinuous trackway consisted of 2 tracks attributed to K. ?dodsoni. Species identification of 3 isolated tracks not available.
Plants Plants reported from the Sanbukdong FormationGenus Species Location Stratigraphic positionMaterialNotesImagesPseudofrenelopsisP. sp. P. cf. parceramosaLeaves CupressinocladusC. sp.LeavesTaxodiaceaeindeterminateCone structure
See also List of dinosaur-bearing rock formations
References