Hasandong Formation

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.^[2] Dinosaur remains have been discovered from this formation, though no genus is considered valid as of 2016.^[3] Other reptiles from the formation include the adocid turtle Proadocus and possibly the pterosaur Dsungaripterus.^[4][5][6]

Hasandong Formation
Stratigraphic range: Aptian-Albian ~118.0–112.4 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Unit of	Shindong Group
Underlies	Jinju Formation
Overlies	Nakdong Formation
Thickness	1,200 metres
Lithology
Primary	Mudstone
Other	Shale, sandstone
Location
Coordinates	35.1°N 128.0°E / 35.1; 128.0
Approximate paleocoordinates	41.3°N 128.1°E / 41.3; 128.1
Region	Gyeongsang Province
Country	South Korea
Type section
Named for	Hasandong(Now called Hasan-ri), Daegu
Named by	Tateiwa, 1929[1]
Hasandong Formation (South Korea)

Fossil content

Invertebrate fossils

Few fragments of insects have been discovered from the formation.^[7]

Molluscs

Molluscs reported from the Hasandong Formation[6]
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[8]	V. sp.				Architaenioglossan gastropod, probably V. keishoensis
Probaicalia	P. katoensis[9]				Hydrobiidae gastropod; species previously assigned to the genus Micromelania

Ostracods

Ostracod carapaces have been discovered from the formation.^[7]

Ostracods reported from the Hasandong Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Cypridea	C. cf. trita[10][11]

Vertebrate fossils

Actinopterygii

Ray-finned fish reported from the Hasandong Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Sinamia[12]	S. sp.			Partial Skeleton
Lepidotes[7]	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
Proadocus[4]	P. hadongensis			Partial Skeleton	Adocid turtle

Crocodylomorpha

Several teeth remains have been reported but are not assigned to the specific clade.^[13]

Crocodylomorphs reported from the Hasandong Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
"Hadongsuchus"[14]	"H. acerdentis"			Skull	nomen nudum

Pterosaurs

Pterosaurs reported from the Hasandong Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Pterodactyloidea[15][16][17]	Indeterminate			Teeth and a partial second wing phalanx	Dental remains belong to either Boreopteridae or Anhanguerian
Dsungaripterus	D.? cf. D. weii[5][6]			Incomplete wing phalanx belonging to Dsungaripteridae[18][19]

Dinosaurs

Several indeterminate theropod teeth remains have been reported.^[20]

Dinosaurs reported from the Hasandong Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Carcharodontosauridae[21][22]	Indeterminate			Teeth	Some dental remains show similarities with Acrocanthosaurus
Hadrosauroidea[23]	Indeterminate			Tooth
Titanosauriformes[24][25][26]	Indeterminate			A partial skeleton and several teeth showing different morphotypes	Includes Chiayusaurus sp. and Pukyongosaurus milleniumi, both of which are nomen dubium
Tyrannosauroidea[27]	Indeterminate			Tooth, estimated crown length ~18mm

Eggs

Unnamed dinosaur egg fossils have been reported.^[28]

Eggs reported from the Hasandong Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Testudoolithus[7]	T. aff. curiosa				Turtle eggs

Ichnofossils

Tracks of theropods, sauropods and ornithopods have been discovered from the formation.^[7][29] Possible amphibian tracks are also known.^[30]

Ichnofossils reported from the Hasandong Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Pteraichnus[30]	P. koreanensis				Pterosaur tracks
Sauripes[31]	S. hadongensis				The oldest lizard tracks showing possible bipedalism, though potentially a nomen dubium due to insufficient description and problematic holotype designation[32]
Diplocraterion[33]	D. luniforme
Beaconites	B. coronus[29]
Circulichnus	C. montanus[29]
Cochlichnus	C. anguineus[29]
Chondrites	C. isp.[29]
Helminthopsis	H. abeli & H. hieroglyphica[29]
Laevicyclus	L. isp.[29]
Planolites	P. annularius, P. beverleyensis & P. montanus[29]
Skolithos	S. magnus, S. verticalis & S. isp.[29]
Spirodesmos	S. isp.[29]
Taenidium	T. barretti[29]
Thalassinoides	T. paradoxicus & T. suevicus[29]

Paleoflora

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.

Plants reported from the Hasandong Formation[34][30]
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Brachyphyllum	B. japonicum				Araucariaceae conifer
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

Hasandong Formation in Uiseong County

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  36°27′10.0″N 128°30′40.0″E
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  Boundary of Hasandong Formation (under) and Jinju Formation (upper)
  36°24′04.0″N 128°32′40.0″E
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Seaside Hasandong Formation in Sulsang-Yangpo Area, Jingyo District, Hadong County

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  35°00′15.8″N 127°55′16.7″E
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  35°00′15.7″N 127°55′17.7″E
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  34°59′59.6″N 127°55′08.2″E
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  35°00′02.8″N 127°55′10.0″E
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  Ripple marks 35°00′02.0″N 127°55′09.6″E
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  Normal Faults 34°59′59.6″N 127°55′08.1″E
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  34°59′59.7″N 127°55′08.1″E
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  34°59′23.9″N 127°55′09.1″E

Seaside Hasandong Formation in Daechiri Area, Geumnam District, Hadong County

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  34°57′31.2″N 127°53′52.6″E
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  34°57′32.9″N 127°53′53.8″E
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  34°57′33.8″N 127°53′53.9″E
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  34°57′33.8″N 127°53′53.9″E
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  34°57′34.1″N 127°53′53.8″E
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  34°57′29.6″N 127°53′41.0″E
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  34°57′29.3″N 127°53′39.9″E
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  34°57′27.3″N 127°53′43.0″E
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  34°57′27.4″N 127°53′43.0″E
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  34°57′27.0″N 127°53′43.1″E

Seaside Hasandong Formation in Songmunri Area, Geumnam District, Hadong County

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  34°56′50.8″N 127°51′08.1″E
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  Cross-bedding 34°56′50.9″N 127°51′08.5″E
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  34°56′50.6″N 127°51′08.7″E
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  Cross-bedding 34°56′50.9″N 127°51′08.5″E
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  Cross-bedding 34°56′51.0″N 127°51′08.7″E
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  34°56′51.1″N 127°51′08.3″E
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  34°56′51.6″N 127°51′08.5″E
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  34°57′28.2″N 127°48′37.1″E

See also

• List of dinosaur-bearing rock formations
  • List of stratigraphic units with few dinosaur genera
• Seonso Conglomerate
• Haman Formation