Hasandong Formation

Hasandong Formation
Stratigraphic range: Aptian-Albian
~118.0–112.4 Ma
Outcrop of the Hasandong Formation in Hasanri, Daegu
TypeGeological formation
Unit ofShindong Group
UnderliesJinju Formation
OverliesNakdong Formation
Thickness1,200 metres
Lithology
PrimaryMudstone
OtherShale, sandstone
Location
Coordinates35°06′N 128°00′E / 35.1°N 128.0°E / 35.1; 128.0
Approximate paleocoordinates41°18′N 128°06′E / 41.3°N 128.1°E / 41.3; 128.1
RegionGyeongsang Province
CountrySouth Korea
Type section
Named forHasandong(Now called Hasan-ri), Daegu
Named byTateiwa, 1929
Hasandong Formation is located in South Korea
Hasandong Formation
Hasandong Formation (South Korea)

The Hasandong Formation (Korean: 하산동층; RR: Hasandong-cheung) is a Lower Cretaceous geologic formation in South Korea. It has been dated to the Aptian to possibly the earliest Albian stage.

The Hasandong Formation could be distinguished from the underlying Nakdong Formation and the overlying Jinju Formation by frequent intercalations of reddish beds. The paleoenvironment of this formation represents a floodplain with a meandering channel including occasional pond deposits. Meanwhile, the paleoclimate has been interpreted as a seasonal alternation of wet and dry seasons.

Based on detrital zircons, Lee et al. 2010 and 2018 estimated the maximum depositional age of the formation at 118.0 ± 2.6 Ma, and suggested that the overlying Jinju Formation likely had a maximum depositional age of 112.4 ± 1.3 Ma. Chae et al. (2026) examined two fossiliferous localities of the upper Hasandong Formation on Yusu-ri, Jinju and on Jangguseom Island of Jungpyeong-ri, Hadong, and estimated the maximum depositional age on each site at 116.9 ± 1.5 Ma and 113.4 ± 1.4 Ma respectively. Fossils including plants, molluscs, diverse vertebrate remains including dinosaurs, turtles, and pterosaurs are known from this formation.

Fossil content

Invertebrate fossils

Few fragments of insects have been discovered from the formation.

Molluscs

Molluscs reported from the Hasandong Formation
Genus Species Location Stratigraphic position Material Notes Images
Plicatounio P. naktongensis
P. okjuni
P. yooni
Nagdongia N. soni
Trigonioides T. jaehoi
T. kodairai
T. tamurai
Brotiopsis B. kobayashii
B. naktongensis
B. ryohoriensis
B. wakinoensis
Viviparus V. sp. Architaenioglossan gastropod, probably V. keishoensis
Probaicalia P. katoensis Hydrobiidae gastropod; species previously assigned to the genus Micromelania

Ostracods

Ostracod carapaces have been discovered from the formation.

Ostracods reported from the Hasandong Formation
Genus Species Location Stratigraphic position Material Notes Images
Cypridea C. cf. trita

Vertebrate fossils

Actinopterygii

Ray-finned fish reported from the Hasandong Formation
Genus Species Location Stratigraphic position Material Notes Images
Sinamia S. sp. Partial Skeleton
Lepidotes L. sp. Partial Skeleton

Testudines

Shell fragments of testudines have been discovered.

Turtles reported from the Hasandong Formation
Genus Species Location Stratigraphic position Material Notes Images
Byeoljubuchelys B. yeosuensis Nearly complete carapace and plastron and associated post-cranial bones A carettochelyid turtle
Proadocus P. hadongensis Partial Skeleton An adocid turtle

Crocodylomorpha

Several teeth remain have been reported but are not assigned to the specific clade.

Crocodylomorphs reported from the Hasandong Formation
Genus Species Location Stratigraphic position Material Notes Images
"Hadongsuchus" "H. acerdentis" Skull nomen nudum

Pterosaurs

Pterosaurs reported from the Hasandong Formation
Genus Species Location Stratigraphic position Material Notes Images
Pterodactyloidea Indeterminate Teeth and a partial second wing phalanx Dental remains belong to either Boreopteridae or Anhanguerian
Dsungaripterus D.? cf. D. weii Incomplete wing phalanx belonging to Dsungaripteridae

Dinosaurs

Several indeterminate theropod teeth remains have been reported.

Dinosaurs reported from the Hasandong Formation
Genus Species Location Stratigraphic position Material Notes Images
Carcharodontosauridae Indeterminate Teeth Some dental remains show similarities with Acrocanthosaurus
Hadrosauroidea Indeterminate Tooth
Titanosauriformes Indeterminate A partial skeleton and several teeth showing different morphotypes Includes Chiayusaurus sp. and Pukyongosaurus milleniumi, both of which are nomen dubium
Tyrannosauroidea Indeterminate Tooth, estimated crown length ~18mm

Eggs

Unnamed dinosaur egg fossils have been reported.

Eggs reported from the Hasandong Formation
Genus Species Location Stratigraphic position Material Notes Images
Testudoolithus T. aff. curiosa Turtle eggs

Ichnofossils

Tracks of theropods, sauropods and ornithopods have been discovered from the formation. Possible amphibian tracks are also known.

Ichnofossils reported from the Hasandong Formation
Genus Species Location Stratigraphic position Material Notes Images
Pteraichnus P. koreanensis Pterosaur tracks
Sauripes S. hadongensis The oldest lizard tracks showing possible bipedalism, though potentially a nomen dubium due to insufficient description and problematic holotype designation
Diplocraterion D. luniforme
Beaconites B. coronus
Circulichnus C. montanus
Cochlichnus C. anguineus
Chondrites C. isp.
Helminthopsis H. abeli & H. hieroglyphica
Laevicyclus L. isp.
Planolites P. annularius, P. beverleyensis & P. montanus
Skolithos S. magnus, S. verticalis & S. isp.
Spirodesmos S. isp.
Taenidium T. barretti
Thalassinoides T. paradoxicus & T. suevicus

Paleoflora

Macroflora of the Hasandong Formation suggests a shift toward seasonally semiarid conditions, dominated by conifers, compared to the underlying Nakdong Formation.

Plants reported from the Hasandong Formation
Genus Species Location Stratigraphic position Material Notes Images
Brachyphyllum B. japonicum Conifer with an unknown systematic position
Cladophlebis C. denticulata
C. (Eboracia?) lobifolia
C. (Klukia?) koraiensis
C. shinshuensis
Elatocladus E. tennerima Conifer with an unknown systematic position
Onychiopsis O. elongata Leptosporangiate fern
Ptilophyllum P. sp. Bennettitales (extinct order of seed plants)
Ruffordia R. sp. Schizaeaceae ferns
Taeniopteris T.? sp. cf. T. auriculata The specific systematic position of this form genus is unknown.
Thallites T. yabei Liverwort

Photo

See also

References

  1. ↑ Tateiwa, Iwao (1929). "Geologic Atlas of Korea, No. 10, Gyeongju, Yeongcheon, Daegu, Waegwan Sheets". Geological Survey of Chosen (Korea).
  2. ↑ Sung Paik, In; Joo Kim, Hyun; Hun Park, Kye; Sun Song, Yong; Il Lee, Yong; Yeon Hwang, Jin; Huh, Min (1 October 2001). "Palaeoenvironments and taphonomic preservation of dinosaur bone-bearing deposits in the Lower Cretaceous Hasandong Formation, Korea". Cretaceous Research. 22 (5): 627–642. doi:10.1006/cres.2001.0282.
  3. 1 2 Lee, Jaemin; Kim, Kyung Soo; Looy, Cindy V. (20 March 2026). "An Early Cretaceous temperate intermontane savanna from South Korea, and its biogeographic implications". Cretaceous Research 106387. doi:10.1016/j.cretres.2026.106387.
  4. ↑ Lee, Tae-Ho; Park, Kye-Hun; Chun, Jong-Hwa; Yi, Keewook (2010). "SHRIMP U-Pb Zircon Ages of the Jinju Formation and Silla Conglomerate, Gyeongsang Basin". The Journal of the Petrological Society of Korea. 19 (1): 89–101.
  5. ↑ 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. S2CID 135061525.
  6. ↑ Chae, Yong-Un; Choi, Taejin; Joo, Young Ji; Kim, Kyung Soo; Ha, Sujin; Lim, Hyoun Soo (2026). "Effective application of multidimensional scaling for detrital zircon geochronology in the southern Miryang Subbasin, Gyeongsang Basin, Korea". Journal of Asian Earth Sciences. 299 106954. doi:10.1016/j.jseaes.2026.106954.
  7. 1 2 3 4 5 Choi, S.; Kim, H.; Paik, I.; Park, Y.; Jung, H.; Xu, X. (2023). "Turtle eggs from the Lower Cretaceous Hasandong Formation (South Korea) with relict aragonite under significant thermal maturity". Journal of Vertebrate Paleontology. 42 (4). e2183866. doi:10.1080/02724634.2023.2183866.
  8. 1 2 Kim, Jeong Yul; Huh, Min (2018). Dinosaurs, Birds, and Pterosaurs of Korea: A Paradise of Mesozoic Vertebrates (PDF). Springer Nature. ISBN 978-981-10-6998-7.
  9. ↑ Yun, Cheol-Soo; Yang, Seung-Yeong (2001). "Cretaceous Non-marine Molluscan Fauna From the Euiseong Subbasin in Korea". Journal of the Paleontological Society of Korea. 17 (1): 1–14 – via DBpia.
  10. ↑ 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. S2CID 257962930.
  11. ↑ 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.
  12. ↑ 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.
  13. ↑ Yabumoto, Y.; Yang, S.Y.; Kim, T.W. (2006). "Early Cretaceous freshwater fishes from Japan and Korea" (PDF). Journal of the Paleontological Society of Korea. 22 (1): 119–132.
  14. ↑ Kim, Minguk; Jung, Jongyun; Joyce, Walter G.; Park, Jae-Il; Jung, Hye-Yeon; Jo, Hyemin; Huh, Min (2025-12-08). "A new, Early Cretaceous carettochelyid turtle from South Korea provides insights into softshell evolution and aquatic ecology". Swiss Journal of Palaeontology. 144 (1). doi:10.1186/s13358-025-00415-z. ISSN 1664-2376.
  15. ↑ Kim, 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. 105665. Bibcode:2023CrRes.15105665K. doi:10.1016/j.cretres.2023.105665.
  16. ↑ 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.
  17. ↑ 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.
  18. ↑ Park, J.-Y.; Lee, S.; Kim, S.-H.; Son, M.; Lee, Y.-N. (2020). "A pterosaur wing phalanx from the Lower Cretaceous Hasandong Formation of Hadong-gun, Gyeongsangnam-do, South Korea" 경상남도 하동군 하부 백악기 하산동층에서 산출된 익룡 지골 화석 [A pterosaur wing phalanx from the Lower Cretaceous Hasandong Formation of Hadong-gun, Gyeongsangnam-do, South Korea] (PDF). Journal of the Geological Society of Korea. 56 (1): 77–84. doi:10.14770/jgsk.2020.56.1.77. S2CID 216159474.
  19. ↑ Yun, Chan-Gyu (2021). "Boreopterid pterosaur fossils from South Korea reconsidered". New Mexico Museum of Natural History and Science Bulletin. 82: 567–568.
  20. ↑ Yun, Chan-Gyu (2024). "Geometric morphometric approach to establish phylogenetic affinities of enigmatic pterosaur specimens from the Lower Cretaceous of South Korea". Acta Palaeontologica Romaniae. 20 (1): 77–86. doi:10.35463/j.apr.2024.01.06.
  21. ↑ Yang, 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.
  22. ↑ Lim, Jong-Deock; Baek, Kwang-Seok; Yang, Seung Young (2002). "A new record of a pterosaur from the Early Cretaceous of Korea". Current Science. 82 (10): 1208–1210. JSTOR 24107042.
  23. ↑ Augustin FJ, Matzke AT, Maisch MW, Pfretzschner HU (2021). "New information on Lonchognathosaurus (Pterosauria: Dsungaripteridae) from the Lower Cretaceous of the southern Junggar Basin (NW China)". Cretaceous Research. 124 104808. Bibcode:2021CrRes.12404808A. doi:10.1016/j.cretres.2021.104808. S2CID 233790566.
  24. ↑ Choi, Seung; Lee, Yuong-Nam (2017-12-01). "A review of vertebrate body fossils from the Korean Peninsula and perspectives". Geosciences Journal. 21 (6): 867–889. Bibcode:2017GescJ..21..867C. doi:10.1007/s12303-017-0040-6. ISSN 1598-7477.
  25. ↑ Lee, Yuong-Nam (30 June 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. doi:10.14770/jgsk.2007.43.2.151.
  26. ↑ Chan-gyu Yun (2020). "A Carcharodontosaurid tooth from the Hasandong Formation (Lower Cretaceous) of South Korea". Mongolian Geoscientist. 50: 2–10. doi:10.5564/mgs.v50i0.1325.
  27. ↑ Lee, Yuong-Nam; Lee, Hang-Jae (2007). "The first ornithopod tooth in Korea". Journal of the Paleontological Society of Korea. 23 (213–225).
  28. ↑ 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.
  29. ↑ 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.
  30. ↑ 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.
  31. ↑ Park, J.-Y. (2016). "Comments on the validity of the taxonomic status of "Pukyongosaurus" (Dinosauria: Sauropoda)" (PDF). Memoir of the Fukui Prefectural Dinosaur Museum. 15: 27–32.
  32. ↑ Lee, Yuong-Nam (2008-03-01). "The first tyrannosauroid tooth from Korea". Geosciences Journal. 12 (1): 19–24. Bibcode:2008GescJ..12...19L. doi:10.1007/s12303-008-0003-z. ISSN 1598-7477.
  33. ↑ 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.
  34. 1 2 3 4 5 6 7 8 9 10 11 12 Kim, 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.
  35. ↑ Kim, Seongyeong; Lee, Yuong-Nam; Gihm, Yong Sik (July 2026). "A running ornithopod trackway from the Hasandong Formation (Lower Cretaceous, Korea): Evidence of a 'Goldilocks' substrate window and rapid avulsion burial". Palaeoworld 201155. doi:10.1016/j.palwor.2026.201155.
  36. 1 2 3 Lee, Y.-N.; Lee, H.-J.; Lü, J.; Kobayashi, Y. (2008). "New pterosaur tracks from the Hasandong Formation (Lower Cretaceous) of Hadong County, South Korea" (PDF). Cretaceous Research. 29 (2): 345–353. Bibcode:2008CrRes..29..345L. doi:10.1016/j.cretres.2007.05.004.
  37. ↑ Lee, H.J.; Lee, Y.N.; Fiorillo, A.R.; Lü, J. (2018). "Lizards ran bipedally 110 million years ago". Scientific Reports. 8 (1): 2617. Bibcode:2018NatSR...8.2617L. doi:10.1038/s41598-018-20809-z. PMC 5814403. PMID 29449576.
  38. ↑ Kim, Kyung Soo; Lim, Jong Deock; Lockley, Martin G.; Kim, Dong Hee; Pinuela, Laura; Yoo, Jae Sang (2019). "Largest Cretaceous lizard track assemblage, new morphotypes and longest trackways comprise diverse components of an exceptional Korean Konservat-Lagerstätten ichnofauna". Scientific Reports. 9 (1): 13278. Bibcode:2019NatSR...913278K. doi:10.1038/s41598-019-49442-0. PMC 6746761. PMID 31527673.
  39. ↑ J.-Y., Kim; I. S., Paik (1997). "Nonmarine Diplocraterion luniforme (Blanckenhorn 1916) from the Hasandong Formation (Cretaceous) of the Jinju area, Korea". Ichnos. 5 (2): 131–138. Bibcode:1997Ichno...5..131K. doi:10.1080/10420949709386412.
  40. ↑ Kim, Jong-Heon; Nam, Kye-Soo; Lee, Seong-Bok; Jeon, Yeong-Seok (2016). "Fossil Plants from the Early Cretaceous Hasandong Formation of Chilgok Area, Korea" (PDF). Journal of the Korean Earth Science Society. 37 (5): 295−308. doi:10.5467/JKESS.2016.37.5.295.

Bibliography