Ilek Formation

Ilek Formation
Stratigraphic range: Lower Cretaceous
Type Geological formation
Unit of Kiya River Basin
Underlies Kiya Formation
Overlies Tyazhin Formation
Thickness Up to 746 metres (2,450 ft)
Lithology
Primary Clay, siltstone
Other Marl, sandstone
Location
Coordinates 55°54′N 88°00′E / 55.9°N 88.0°E / 55.9; 88.0Coordinates: 55°54′N 88°00′E / 55.9°N 88.0°E / 55.9; 88.0
Approximate paleocoordinates 54°12′N 84°36′E / 54.2°N 84.6°E / 54.2; 84.6
Region Western Siberia
Country  Russia
Extent  Kemerovo Oblast
Type section
Named by L. A. Ragozin
Year defined 1935

The Ilek Formation is a Lower Cretaceous geologic formation in Western Siberia. Many different fossils have been recovered from the formation. It overlies the Late Jurassic Tyazhin Formation and underlies the Albian Kiya Formation.[1]

The formation was described by L. A. Ragozin in 1935. It consists of sands with sandstone concretions, layers of silts, clays and marls.[2] Age of the formation, according to a crude 1962 estimate, is Valanginian(?) - Hauterivian - Barremian. Its thickness varies greatly, reaching 746 m in Teguldet borehole.[3]

Fauna

Avialans reported from the Ilek Formation
Genus Species Location Stratigraphic position Material Notes Images
Evgenavis[4] E. nobilis Siberia a set of limb elements A confuciusornithiform
Mystiornis[5] M. cyrili Western Siberia Shestakovo-1 locality Isolated metatarsus An avisaurid enantiornithean
Dinosaurs reported from the Ilek Formation
Genus Species Location Stratigraphic position Material Notes Images
Psittacosaurus[6] P. sibiricus Western Siberia Shestakovo Several skeletons A ceratopsian
Sibirotitan[7] S. astrosacralis Western Siberia vertebrae, sacrum, and previously published pedal elements A somphospondyli
Crocodylomorphs reported from the Ilek Formation
Genus Species Location Stratigraphic position Material Notes Images
Kyasuchus[8] K. saevi Siberia a partial skull a shartegosuchid crocodyliform
Tagarosuchus[9] T. kulemzini Southern Siberia Shestakovo Nearly complete skull A crocodyliform
Mammaliaformes reported from the Ilek Formation
Genus Species Location Stratigraphic position Material Notes Images
Acinacodus[10] A. tagaricus Western Siberia right dentary fragment An amphidontid mammal
Baidabatyr[11] B. clivosus Siberia Bol'shoi Kemchug 3 locality upper premolar a multituberculate

Gobiconodon

G. hoburensis[12]

Siberia

 21 upper and lower jaws. A gobiconodont

G. borissiaki[13]

 Siberia 1 fragmentary lower jaw A gobiconodont
Kemchugia[14] K. magna a tooth a amphilestid mammal
Kiyatherium[15] K. cardiodens Western Siberia a maxilla a zhangheotheriid mammal
Sibirotherium[16] S. rossicus Siberia lower jaw fragments A docodont mammaliaform
Xenocretosuchus[17] X. sibiricus Siberia Dental elements A tritylodont mammaliaform
Yermakia[18] Y. domitor Siberia Shestakovo-1 locality a mandible a tinodontid mammal
Amphibians reported from the Ilek Formation
Genus Species Location Stratigraphic position Material Notes Images
Kiyatriton K. leshchinskiyi Western Siberia a set of vertebrae A salamander
Lizards reported from the Ilek Formation
Genus Species Location Stratigraphic position Material Notes Images
Ilekia[19] I. sibirica Western Siberia Bol'shoi Kemchug 3 locality A member of paramacellodidae
Shestakovia S. voronkevichi Western Siberia Bol'shoi Kemchug 3 locality A knob-scaled lizard

See also

References

  1. ↑ Golovneva, L. B.; Shchepetov, S. V. (2010-04). "Phytostratigraphy of Albian-Cenomanian sediments in the Kiya River basin (the Chulym-Yenisei area of the west Siberian lowland)". Stratigraphy and Geological Correlation. 18 (2): 153–165. doi:10.1134/s0869593810020048. ISSN 0869-5938. Check date values in: |date= (help)
  2. ↑ Криштофович А. Н., ed. (1955). "Илекская свита". Геологический словарь. 1 (А-Л). p. 271.
  3. ↑ Лебедев И. В., ed. (1962). Биостратиграфия мезозойских и третичных отложений Западной Сибири. pp. 168–169.
  4. ↑ O'Connor, JL; Averianov, AO; Zelenkov, NV (2014). "A confuciusornithiform (Aves, Pygostylia)-like tarsometatarsus from the Early Cretaceous of Siberia and a discussion of the evolution of avian hind". Journal of Vertebrate Paleontology. 34 (3): 647–656. doi:10.1080/02724634.2013.828734.
  5. ↑ Evgeny N. Kurochkin; Nikita V. Zelenkov; Alexandr O. Averianov; Sergei V. Leshchinskiy (2011). "A new taxon of birds (Aves) from the Early Cretaceous of Western Siberia, Russia". Journal of Systematic Palaeontology. 9 (1): 109–117. doi:10.1080/14772019.2010.522202.
  6. ↑ Averianov, Alexander O.; Voronkevich, Alexei V.; Leshchinskiy, Sergei V.; Fayngertz, Alexei V. (2006). "A ceratopsian dinosaur Psittacosaurus sibiricus from the Early Cretaceous of West Siberia, Russia and its phylogenetic relationships". Journal of Systematic Palaeontology. 4 (4): 359–395. doi:10.1017/s1477201906001933.
  7. ↑ Alexander Averianov; Stepan Ivantsov; Pavel Skutschas; Alexey Faingertz; Sergey Leshchinskiy (2018). "A new sauropod dinosaur from the Lower Cretaceous Ilek Formation, Western Siberia, Russia". Geobios. in press. doi:10.1016/j.geobios.2017.12.004.
  8. ↑ Efimov, M. B. and Leshchinskiy, S. V. (2000). First finding of the fossil crocodile skull in Siberia [in Russian]. In: Komarov, A. V., ed., Materialy regional’noj konferencii geologov Sibiri, Dal’nego Vostoka i Severo−Vostoka Rossii. Tom II, 361–363. GalaPress, Tomsk.
  9. ↑ Fiorelli, L.E.; Calvo, J.O. (2007). "The first "protosuchian" (Archosauria: Crocodyliformes) from the Cretaceous (Santonian) of Gondwana" (PDF).
  10. ↑ A. V. Lopatin; E. N. Maschenko & A. O. Averianov (2010). "A new genus of triconodont mammals from the Early Cretaceous of Western Siberia". Doklady Biological Sciences. 433 (1): 282–285. doi:10.1134/S0012496610040137.
  11. ↑ Alexander Averianov; Alexey Lopatin; Pavel Skutschas; Stepan Ivantsov; Elizaveta Boitsova; Ivan Kuzmin (2017). "An enigmatic multituberculate mammal from the Early Cretaceous of Siberia, Russia". Journal of Vertebrate Paleontology. 37 (2): e1293070. doi:10.1080/02724634.2017.1293070.
  12. ↑ Trofimov, B. A. (1978). "The first triconodonts (Mammalia, Triconodonta) from Mongolia". Doklady Akademii Nauk SSSR. 243 (1): 213–216.
  13. ↑ Maschenko, E. N.; Lopatin, A. V. (1998). "First record of an Early Cretaceous triconodont mammal in Siberia". Bull. Inst. R. Sci. Nat. Belg. 68: 233–236.
  14. ↑ A. V. Lopatin, E. N. Maschenko, A. O. Averianov, A. S. Rezvyi, P. P. Skutschas and S. V. Leschinskiy. 2005. Early Cretaceous Mammals from Western Siberia: 1. Tinodontidae. Paleontological Journal 39(5):523-534
  15. ↑ E. N. Maschenko and A. V. Lopatin. 2002. A new Early Cretaceous mammal from Western Siberia. Doklady Biological Sciences 386:475-477
  16. ↑ http://zmmu.msu.ru/rjt/articles/article.php?volume=1&issue=2&pages=75-81
  17. ↑ http://fossilworks.org/cgi-bin/bridge.pl?a=taxonInfo&taxon_no=254183
  18. ↑ A. V. Lopatin, E. N. Maschenko, A. O. Averianov, A. S. Rezvyi, P. P. Skutschas and S. V. Leschinskiy. 2005. Early Cretaceous Mammals from Western Siberia: 1. Tinodontidae. Paleontological Journal 39(5):523-534
  19. ↑ A. O. Averianov, P. P. Skutschas, A. V. Lopatin, S. V. Leschinskiy, A. S. Rezvyi and A. V. Fayngerts. 2005. Early Cretaceous mammals from Bol'shoi Kemchug 3 locality in West Siberia, Russia. Russian Journal of Theriology 4(1):1-12
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