Alai Beds

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Alai Beds
Stratigraphic range: Ypresian
(Bumbanian)
~55.8–48.6  Ma
Type Geological formation
Overlies Paleozoic rocks
ThicknessMore than 25 m (82 ft)
Lithology
Primary Siltstone, conglomerate
Other Limestone
Location
Coordinates 39°54′N69°30′E / 39.9°N 69.5°E / 39.9; 69.5
Approximate paleocoordinates 40°42′N69°42′E / 40.7°N 69.7°E / 40.7; 69.7
Region Osh
CountryFlag of Kyrgyzstan (2023).svg  Kyrgyzstan
Extent Aktash Range
Relief Map of Kyrgyzstan.png
Orange pog.svg
Alai Beds (Kyrgyzstan)

The Alai Beds is an Early Eocene (Ypresian, or Bumbanian in the ALMA classification) geologic formation in the Osh Region of southwestern Kyrgyzstan. The formation has provided many fossils of mammals, lizards, turtles and snakes. [1]

Contents

Description

The Paleogene Alai Beds have a limited distribution, and are restricted to the northern slope of Aktash Range, formed by Paleozoic rocks, which is one of the foothills of the Turkestan Range. The Paleogene deposits on the Aktash Range are badly exposed, they can be observed only in three outcrops, separated by short distances about 1 to 2 kilometres (0.62 to 1.24 mi). Despite their close position, the Paleogene deposits in these outcrops are varied greatly in composition and thickness of layers. [2]

The lower Alai Beds contain 5 metres (16 ft) of silts and siltstones, and the upper part comprises oyster-bearing limestones of which 2 to 3 metres (6 ft 7 in to 9 ft 10 in) are exposed. At the base of the Upper Alai Beds there is a layer of conglomerate which produces a number of marine vertebrates, but a few terrestrial vertebrates including mammals. The section I1 is more complete and has a greater thickness, but produces a few shark teeth only. The third Paleogene section, where the mammal bearing locality Andarak 2 is located, has a much greater thickness of sands of the lower Alai Beds (more than 25 metres (82 ft) of visible thickness) with some horizons of oyster-bearing conglomerates. [3]

Fossil content

The formation has provided the following fossils: [1]

Mammals

Artiodactyls
Cimolesta
Hyaenodonta
Lipotyphla
Perissodactyls
Rodents

Reptiles

Lizards
Snakes
Turtles

See also

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References

  1. 1 2 Alai Beds at Fossilworks.org
  2. Averianov, 1994a, p.399
  3. Averianov, 1994a, p.400
  4. 1 2 3 4 5 Averianov & Danilov, 1996b
  5. 1 2 Averianov, 1994b
  6. Lopatin & Averianov, 2004
  7. 1 2 Lopatin, 2006
  8. 1 2 Lavrov & Averianov, 1998
  9. 1 2 3 4 Averianov & Godinot, 2005
  10. Averianov, 1994a, p.406
  11. Averianov & Lopatin, 2005
  12. Averianov, 1994a, p.401
  13. Averianov, 1994a, p.402
  14. Lopatin & Averianov, 2006
  15. 1 2 3 4 5 6 Averianov & Danilov, 1996a
  16. Averianov & Danilov, 1997
  17. Danilov & Averianov, 1999
  18. 1 2 3 Danilov & Averianov, 1999
  19. Averianov, 2002

Bibliography