Karabastau Formation

The Karabastau Formation (Kazakh: Qarabastaý svıtasy) is a geological formation and lagerstätte in the Karatau Mountains of southern Kazakhstan whose strata date to the Middle to Late Jurassic. It is an important locality for insect fossils that has been studied since the early 20th century, alongside the rarer remains of vertebrates, including pterosaurs, salamanders, lizards and crocodiles.[1][2]

Karabastau Formation
Stratigraphic range: Middle Jurassic - Late Jurassic
Specimen of the salamander Karaurus sharovi
TypeGeological formation
AreaKaratau Mountains
Thickness26 m (85 ft) exposed
Lithology
PrimaryClaystone dolomite,
OtherSandstone, conglomerate
Location
RegionCentral Asia
Country Kazakhstan

Lithology and depositional environment
Fossil wasp Arkadiserphus (Peleserphidae)

The primary lithology consists of 1 mm thick varve laminations of claystone, with a dark part and a light dolomitic part, which probably correspond to a wet and dry season respectively, alongside rare, several cm thick sandstone interbeds. These were deposited within an ancient freshwater paleolake, that given the number of laminations has been suggested to have existed for over 150,000 years. The top of the formation shows the laminations becoming wavy, likely as a result of microbial interactions, and the top of the formation is capped by a conglomerate predominantly composed of black Carboniferous limestone pebbles.[2]

History of discovery

The Karabastau Formation was first discovered in 1921 by Soviet geologists, and was declared a protected paleontological reserve in 1924.[2]

Paleofauna

Vertebrates
Genus Species County Member Abundance Notes Images

Batrachognathus

B. volans

 2 specimens

An Anurognathid Pterosaur.
Sordes pilosus
Morrolepis aniscowitchi

Karatausuchus

K. sharovi

An Atoposaurid Crocodylomorph.

Karaurus

K. sharovi

stem-group salamander.

Praeornis P. sharovi 2 specimens Proto-Feather
Sharovisaurus S. karatauensis A Paramacellodid lizard

Sordes

 S. pilosus 8 specimens

A Pterodactylomorph Pterosaur.

Yaxartemys Y. longicauda Turtle, possibly belongs to Xinjiangchelyidae
Morrolepis M. aniscowitchi 346 specimens Coccolepidid fish[3]
Pteroniscus P. turkestanensis Palaeonisciform fish, closely related to Uighuroniscidae and Daqingshaniscus.[3]
Spherosteus S. scharovi Peipiaosteid fish, related to sturgeons and paddlefish

Invertebrates

Hundreds of species of insects are known from several localities within the formation, primarily Karatau-Mikhailovka[4][5][6][7][8][9][10][11][12][13]

Flora
Genus Species County Member Abundance Notes Images
Williamsoniella Williamsoniella karataviensis Bennettitales
Weltrichia Weltrichia auliensis
Ptilophyllum
Otozamites
Brachyphyllum Conifer
Pagiophyllum

See also

References
  1. Barrett, P.M., Butler, R.J., Edwards, N.P., & Milner, A.R. Pterosaur distribution in time and space: an atlas. p61-107. in Flugsaurier: Pterosaur papers in honour of Peter Wellnhofer. 2008. Hone, D.W.E., and Buffetaut, E. (eds). Zitteliana B, 28. 264pp.
  2. Dzik, Jerzy; Sulej, Tomasz; Niedźwiedzki, Grzegorz (2010-07-14). "Possible link connecting reptilian scales with avian feathers from the early Late Jurassic of Kazakstan". Historical Biology. 22 (4): 394–402. doi:10.1080/08912961003710616. ISSN 0891-2963. S2CID 55901653.
  3. Skrzycka, Roksana (2014-07-03). "Revision of two relic actinopterygians from the Middle or Upper Jurassic Karabastau Formation, Karatau Range, Kazakhstan". Alcheringa: An Australasian Journal of Palaeontology. 38 (3): 364–390. doi:10.1080/03115518.2014.880267. ISSN 0311-5518. S2CID 129308632.
  4. "Karabastau Formation". paleobiodb.org. Retrieved 2020-01-31.
  5. "Karatau-Galkino (PIN collection 1789)". Paleobiology Database.
  6. "Karatau-Mikhailovka (PIN collection 2997)". Paleobiology Database.
  7. "Karatau-Mikhailovka (PIN collection 2554)". paleobiodb.org. Retrieved 2020-01-31.
  8. "Karatau-Mikhailovka (PIN collection 2066)". paleobiodb.org. Retrieved 2020-01-31.
  9. "Karatau-Mikhailovka (PIN collection 2239)". paleobiodb.org. Retrieved 2020-01-31.
  10. "Karatau-Mikhailovka (PIN collection 2384)". paleobiodb.org. Retrieved 2020-01-31.
  11. "Karatau-Mikhailovka (PIN collection 2904)". paleobiodb.org. Retrieved 2020-01-31.
  12. "Karatau-Mikhailovka (PIN collection 2784)". paleobiodb.org. Retrieved 2020-01-31.
  13. "Karatau-Galkino (PIN collection 2452)". paleobiodb.org. Retrieved 2020-01-31.

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