The Hasandong Formation (Korean: 하산동층; Hanja: 霞山洞層; RR: Hasandong-cheung) is an Early Cretaceous (Aptian to Albian) geologic formation in South Korea. It has been dated to the late Aptian and earliest Albian, between 118.0 ± 2.6 Ma and 112.4 ± 1.3 Ma.[1]Dinosaur remains have been discovered from this formation, though no genus is considered valid as of 2016.[2] Other reptiles from the formation include the adocid turtle Proadocus and possibly the pterosaurDsungaripterus.[3][4][5]
Consists of 6 genera and 9 species. The assemblage of plant fossils from the Hasandong represents the 'mixed' type of Tetori-type and Ryoseki-type flora.
^Lee, Tae-Ho; Park, Kye-Hun; Yi, Keewook (October 2018). "Nature and evolution of the Cretaceous basins in the eastern margin of Eurasia: A case study of the Gyeongsang Basin, SE Korea". Journal of Asian Earth Sciences. 166: 19–31. Bibcode:2018JAESc.166...19L. doi:10.1016/j.jseaes.2018.07.004. S2CID135061525.
^ abKim, D. H.; Lee, Y.-N.; Ko, H.; Park, J.-Y.; Kim, S.-H.; Lee, S.; Jung, S.-H.; Kong, D.-Y. (2023). "The first adocid turtle in South Korea (Lower Cretaceous) and the early evolution of the Adocidae". Cretaceous Research. 151. 105665. Bibcode:2023CrRes.15105665K. doi:10.1016/j.cretres.2023.105665.
^ abYang, S.Y. (2015). "Study history and research ethics of the dinosaur, pterosaur and bird tracks from Korea". Journal of the Geological Society of Korea. 51 (2): 127–140. doi:10.14770/jgsk.2015.51.2.127.
^Isaji, S. (2023). "Molluscan Faunal Changes from Brackish to Freshwater Deposits in the Lower Cretaceous Itsuki Formation of the Tetori Group, Japan". Paleontological Research. 28 (1): 1–25. doi:10.2517/PR220022. S2CID257962930.
^Hayashi, K. (2006). "Nonmarine ostracode zonation and long-distance correlation based on analysis of regional ostracode successions in China, Korea, Japan, and Mongolia". Cretaceous Research. 27 (2): 168–188. Bibcode:2006CrRes..27..168H. doi:10.1016/j.cretres.2005.11.007.
^Qin, Z.-H.; Xi, D.-P.; Choi, B.-D.; Ye, Y.-Q.; Wan, X.-Q. (2021). "Lowermost occurrence of ostracod Cypridea species in East Asia and implications for the non-marine Jurassic/Cretaceous boundary". Palaeoworld. 30 (1): 148–168. doi:10.1016/j.palwor.2020.04.003.
^Yun, Cheol-Soo; Baek, Kwang-Seok; Jeong, Young-Hyeon (2007). "Cretaceous reptilian teeth from the Gyeongsang Basin". Journal of the Paleontological Society of Korea. 23 (1): 27–47.
^Lee, Hang-Jae. A New Protosuchian (Archosauria: Crocodyliformes) Skull from the Hasandong Formation (Lower Cretaceous) of Hadong, Korea. Master's thesis, Chungnam National University, 2005.
^Yun, Chan-Gyu (2021). "Boreopterid pterosaur fossils from South Korea reconsidered". New Mexico Museum of Natural History and Science Bulletin. 82: 567–568.
^Lee, Yuong-Nam (2007). "New theropod teeth from the Juji Island (Hasandong Formation), Daedo-ri, Hadong County, South Gyeongsang Province". Journal of the Geological Society of Korea. 43 (2): 151–166.
^Lee, Yuong-Nam; Lee, Hang-Jae (2007). "The first ornithopod tooth in Korea". Journal of the Paleontological Society of Korea. 23 (213–225).
^Lee, Yuong-Nam; Yang, Seong-Young; Park, Eun-Ju (1997). "Sauropod dinosaur remains from the Gyeongsang Supergroup, Korea". Paleontological Society of Korea Special Publication. 2: 103–114.
^Park, Eun-Ju; Yang, Seong-Young; Currie, Phillip J. (2000). "Early Cretaceous dinosaur teeth of Korea". Paleontological Society of Korea Special Publication. 4: 85–98.
^Z. Dong, I. S. Paik, and H. J. Kim. 2001. A preliminary report on a sauropod from the Hasandong Formation (Lower Cretaceous), Korea. In T. Deng, Y. Wang (eds.), Proceedings of the Eighth Annual Meeting of the Chinese Society of Vertebrate Paleontology 41-53.
^Yun, Cheol-Soo; Yang, Seong-Young (1997). "Dinosaur eggshells from the Hasandong Formation, Gyeongsang Supergroup, Korea". Journal of the Paleontological Society of Korea. 13 (1): 21~36.
^ abcdefghijklKim, J.Y.; Pickerill, R. (2002). "Cretaceous Nonmarine Trace Fossils from the Hasandong and Jinju Formations of the Namhae Area, Kyongsangnamdo, Southeast Korea". Ichnos. 9 (1–2): 41–60. doi:10.1080/10420940190034076.