Ilek Formation

Ilek Formation
Stratigraphic range: Lower Cretaceous,
BarremianAptian
Shestakovo 1 locality
TypeGeological formation
Unit ofKiya River Basin
UnderliesKiya Formation
OverliesTyazhin Formation
ThicknessUp to 746 metres (2,450 ft)
Lithology
PrimaryClay, siltstone
OtherMarl, sandstone
Location
Coordinates55°54′N 88°00′E / 55.9°N 88.0°E / 55.9; 88.0
Approximate paleocoordinates54°12′N 84°36′E / 54.2°N 84.6°E / 54.2; 84.6
RegionWestern Siberia
Country Russia
Extent Kemerovo Oblast
Type section
Named byL. A. Ragozin
Year defined1935
Ilek Formation is located in Russia
Ilek Formation
Ilek Formation (Russia)
Ilek Formation is located in Kemerovo Oblast
Ilek Formation
Ilek Formation (Kemerovo Oblast)

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] A more recent 2024 estimate based on invertebrate and vertebrate fossils placed the age of the formation at Barremian–Aptian.[4]

  1. ^ Cite error: The named reference Golovneva2010 was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference dict_1955 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference Lebedev_1962 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Ivantsov2024 was invoked but never defined (see the help page).