Amisan Formation Explained

Amisan Formation
Type:Geological formation
Period:Norian
Age:Norian
~
Prilithology:Shale, Sandstone, Siltstone
Region:South Chungcheong Province
Unitof:Nampo Group
Underlies:Jogyeri Formation
Overlies:Hajo Formation
Thickness:750-
Extent:Chungnam Basin

The Amisan Formation is an Late Triassic geologic formation in South Korea. Fossil records from this formation include plants, insects, and fish remains.

Geology

The Amisan Formation in the Chungnam Basin overlies the Hajo Formation and underlies the Jogyeri Formation. It is subdivided into five zones based on its lithology, lower sandstone, lower shale, middle sandstone, middle shale, and upper sandstone zones. Depositional environments of the lower and middle shale zones of the Amisan Formation are thought to be lacustrine settings.

The depositional age of the Nampo Group including the Amisan Formation is debated,[1] [2] but plant genera Lobatannularia and Sphenophyllum from the Baegunsa Formation, which overlies the Amisan Formation and the Jogyeri Formation suggests that the Upper Triassic spans to the Baegunsa Formation.[3] Also, conchostracan fossils and some insect fossils support the Triassic origin of the Amisan Formation.[4] [5] [6]

Fossil content

Most of the fossils from the Amisan Formation are from the lower shale zone and the middle shale zone.

Flora

Flora of the Amisan Formation
GenusSpeciesRegionMemberMaterialNotesImage
Taeniopteris[7]
  • T. eurychoron
  • T. mungyeongensis

Ferns

Ferns of the Amisan Formation
GenusSpeciesRegionMemberMaterialNotesImage
NeocalamitesN. carrerei[8]
CladophlebisC. nebbensis[9]
LobatannulariaL. sp.
ChiropterisC. sp.
Equisetites[10]
  • E. kimi
  • E. gaehwariensis
  • E. deltodon

Bennettitales

Bennettitales of the Amisan Formation
GenusSpeciesRegionMemberMaterialNotesImage
AnomozamitesA. baegunsaensis[11]
Pterophyllum
  • P. seongjuriense
  • P. daecheonense
WeltrichiaW. sp.[12]

Gymnosperms

Gymnosperms of the Amisan Formation
GenusSpeciesRegionMemberMaterialNotesImage
Podozamites
  • P. lanceolatus
  • P. var. genuinea
  • P. schenki
  • P. nampoensis
AnthrophyopsisA. sp.
DrepanozamitesD. sp.
BaieraB. cf. furcata[13]
CycadocarpidiumC. sp.
CtenozamitesC. meogbangensis
LeptostrobusL. myeongamensis[14]

Bivalves

Bivalves of the Amisan Formation
GenusSpeciesRegionMemberMaterialNotesImage
MargaritiferaM. cf. isfarensis[15]

Conchostracans

Conchostracans of the Amisan Formation
GenusSpeciesRegionMemberMaterialNotesImage
Euestheria
  • E. kawasakii
  • E. shimamurai
CyclestherioidesC. rampoensis
SphaerestheriaS. koreanica

Insects

Insects of the Amisan Formation
GenusSpeciesRegionMemberMaterialNotesImage
TurbidapsycheM. dobrokhotovaeA mesopsychid scorpionfly.[16]
SiberioperlidaeIndeterminateStoneflies.[17]
PlatyperlaP. sp.
BaleyopterygidaeIndeterminate
HallakkungisH. amisanensisA palaeontinid.[18]
TennentsiaT. koreanaA cicadomorph.[19]
SanmaiS?. zetavenaA tettigarctid.[20]
MagnatitanM. jongheoniA titanopteran.
KoreaphlebiaK. iussradiaeA triadophlebiomorph odonatopteran.
KoreatriassothemisK. elongatusA parazygopteran odonatopteran.[21]
?IsophlebiopteraIndeterminateA possible Isophlebioptern nymph. Referred as Samarura-type'.[22]
ShurabiaS. taewaniA Geinitziid polyneopteran.[23]

Vertebrates

Vertebrates of the Amisan Formation
GenusSpeciesRegionMemberMaterialNotesImage
HiascoactinusH. boryeongensisA redfieldiiform actinopterygian.[24]
MegalomatiaM. minimaA basal actinopterygian.[25]

Notes and References

  1. Jeon . Heejin . Cho . Moonsup . Kim . Hyeoncheol . Horie . Kenji . Hidaka . Hiroshi . Early Archean to Middle Jurassic Evolution of the Korean Peninsula and Its Correlation with Chinese Cratons: SHRIMP U-Pb Zircon Age Constraints . The Journal of Geology . September 2007 . 115 . 5 . 525–539 . 10.1086/519776 . 2007JG....115..525J . en . 0022-1376.
  2. Egawa . Kosuke . Lee . Yong Il . Jurassic synorogenic basin filling in western Korea: sedimentary response to inception of the western Circum-Pacific orogeny . Basin Research . 10 July 2009 . 21 . 4 . 407–431 . 10.1111/j.1365-2117.2009.00408.x . 2009BasR...21..407E . en . 1365-2117.
  3. Kim . Jong Heon . Kimura . Tatsuaki . Lobatannularia nampoensis (Kawasaki) Kawasaki from the Upper Triassic Baegunsa Formation, Nampo Group, Korea . Proceedings of the Japan Academy, Series B . 1988 . 64 . 8 . 221–224 . 10.2183/pjab.64.221 . 1988PJAB...64..221K .
  4. Kim . Jong-Heon . Lee . Gui-Hyeong . Fossil Conchostraca from the Amisan Formation of the Nampo Group, Korea . Journal of the Korean Earth Science Society . 2015 . 36 . 2 . 181–189 . 10.5467/JKESS.2015.36.2.181 .
  5. Park . Tae-Yoon S. . Kim . Do-Yoon . Nam . Gi-Soo . Lee . Mirinae . 2022 . A new titanopteran Magnatitan jongheoni n. gen. n. sp. from southwestern Korean Peninsula . Journal of Paleontology . en . 96 . 5 . 1111–1118 . 10.1017/jpa.2022.30 . 0022-3360. free . 2022JPal...96.1111P .
  6. Jouault . C. . Nam . Gi-Soo . Nel . A. . 2023-09-02 . Koreaphlebia gen. nov. (Odonatoptera: Triadophlebiomorpha): new evidence of a Triassic age for the Amisan Formation in Korea . Historical Biology . en . 35 . 9 . 1551–1555 . 10.1080/08912963.2022.2102492 . 2023HBio...35.1551J . 0891-2963.
  7. Kimura . Tatsuaki . Kim . Bong-Kyun . Geological Age of the Daedong Flora in the Korean Peninsula and its Phytogeographical Significance in Asia . Proceedings of the Japan Academy, Series B . 1984 . 60 . 9 . 337–340 . 10.2183/pjab.60.337. 1984PJAB...60..337K .
  8. Kim . Jong-Heon . Roh . Heon-Sun . Organ Fossils of Neocalamites carrerei from the Amisan Formation of the Nampo Group, Korea . Journal of the Korean Earth Science Society . 2008 . 29 . 6 . 466–473 . 10.5467/JKESS.2008.29.6.466.
  9. Tatsuaki . Kimura . Kim . Bong-Kyun . New taxa in the Late Triassic Daedong Flora, South Korea. Part 1 . Transactions and Proceedings of the Palaeontological Society of Japan . December 20, 1988 . 152 . 603–624.
  10. Kim . Jong-Heon . Three new Equisetites species found from the Upper Triassic Amisan Formation, Nampo Group, Korea . Journal of the Paleontological Society of Korea . June 1990 . 6 . 1 . 91–99.
  11. Kim . Jongheon . New fossil plants from the Nampo Group (Lower Mesozoic), Korea . Geosciences Journal . 1 June 2001 . 5 . 2 . 173–180 . 10.1007/BF02910423 . 2001GescJ...5..173K . en . 1598-7477.
  12. Kim . Jong-Heon . Weltrichia sp. from the Late Triassic Amisan Formation of Nampo Group, Korea . Journal of the Korean Earth Science Society . 2013 . 34 . 5 . 402–406 . 10.5467/JKESS.2013.34.5.402.
  13. Kim . Jong-Heon . Species Diversity and Leaf Form of Ginkgoaleans from the Mesozoic and Cenozoic Strata in Korea . Journal of the Korean Earth Science Society . 2009 . 30 . 1 . 1–9 . 10.5467/JKESS.2009.30.1.001.
  14. Kim . Jong-Heon . Kim . Hee-Soo . Lee . Bong-Jae . Kim . Jung-Min . Lee . Hee-Kwon . A New Species of Leptostrobus from the Upper Triassic Amisan Formation of the Nampo Group in Korea . Journal of the Korean Earth Science Society . 2002 . 23 . 1 . 30–37 .
  15. Kim . Jong Heon . Lee . Chin Kyu . Choi . Dong Yeol . Margaritifera cf. isfarensis (Chernishev) from the Amisan Formation, Nampo Group, Korea. Journal of the Geological Society of Korea . 2015 . 51 . 4 . 357–362. 10.14770/jgsk.2015.51.4.357 .
  16. Kye Soo . Nam . Jong-Heon . Kim . Occurrence of the Fossil Mesopsyche dobrokhotovae in the Late Triassic Amisan Formation, Nampo Group, Korea and its Geological Implication . Journal of the Korean Earth Science Society . 2014 . 35 . 3 . 161–167 . 10.5467/JKESS.2014.35.3.161 .
  17. Nam . Kye Soo . 2017 . Taxonomy and Ecological Implications of Stonefly (Order: Plecoptera) Nymphs from the Late Triassic Amisan Formation in the Boryeong region, Korea . Journal of the Korean Earth Science Society . 38 . 4 . 293–302. 10.5467/JKESS.2017.38.4.293 .
  18. Nam . Kye Soo . Wang . Ying . Ren . Dong . Kim . Jong Heon . Szwedo . Jacek . An extraordinary palaeontinid from the Triassic of Korea and its significance . Scientific Reports . 18 January 2017 . 7 . 1 . 40691 . 10.1038/srep4069 . 1 November 2024 . en . 2045-2322.
  19. Nel . André . Nam . Gi-Soo . Jouault . Corentin . 2022-09-03 . The first Dysmorphoptilidae (Hemiptera: Cicadomorpha) from the Upper Triassic of South Korea . Annales de la Société Entomologique de France . Nouvelle Série . en . 58 . 5 . 455–460 . 10.1080/00379271.2022.2124191 . 0037-9271.
  20. Jouault . Corentin . Nam . Gi-Soo . Boderau . Mathieu . Kwon . Seung-Hyuk . Nel . André . 2024-02-27 . A new Triassic Tettigarctidae (Insecta, Hemiptera) from the Amisan Formation (Republic of Korea) . Palaeoentomology . en . 7 . 1 . 132–140 . 10.11646/palaeoentomology.7.1.9 . 2624-2834.
  21. Nel . André . Nam . Gi-Soo . Jouault . Corentin . 2022-10-02 . First representative of the odonatan superfamily Triassolestoidea (Odonatoptera: Parazygoptera) from the Upper Triassic of the Korean Peninsula . Alcheringa: An Australasian Journal of Palaeontology . en . 46 . 3–4 . 237–243 . 10.1080/03115518.2022.2130426 . 2022Alch...46..237N . 0311-5518.
  22. Nel . André . Nam . Gi-Soo . Jouault . Corentin . 2022-10-02 . First representative of the odonatan superfamily Triassolestoidea (Odonatoptera: Parazygoptera) from the Upper Triassic of the Korean Peninsula . Alcheringa: An Australasian Journal of Palaeontology . en . 46 . 3–4 . 237–243 . 10.1080/03115518.2022.2130426 . 2022Alch...46..237N . 0311-5518.
  23. Jouault . Corentin . Nam . Gi-Soo . Nel . André . 2022-10-01 . The first Geinitziidae (Polyneoptera: Reculida) from the Upper Triassic Amisan Formation of South Korea . Annales de Paléontologie . 108 . 4 . 102558 . 10.1016/j.annpal.2022.102558 . 2022AnPal.10802558J . 0753-3969.
  24. Kim . Su-Hwan . Lee . Yuong-Nam . Park . Jin-Young . Lee . Sungjin . Lee . Hang-Jae . 2020-04-01 . The first record of redfieldiiform fish (Actinopterygii) from the Upper Triassic of Korea: Implications for paleobiology and paleobiogeography of Redfieldiiformes . Gondwana Research . 80 . 275–284 . 10.1016/j.gr.2019.11.008 . 2020GondR..80..275K . 1342-937X.
  25. Kim . Su-Hwan . Lee . Yuong-Nam . Nam . Gi-Soo . Park . Jin-Young . Lee . Sungjin . Son . Minyoung . 2024-01-03 . A new exceptionally well-preserved basal actinopterygian fish in the juvenile stage from the Upper Triassic Amisan Formation of South Korea . Scientific Reports . 14 . 1 . 317 . 10.1038/s41598-023-50803-z . 2045-2322 . 38172381. 10764774 . 2024NatSR..14..317K .

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