Zaza Formation

  (Redirected from Baissa)

The Zaza Formation is a geological formation located in Buryatia (Russia). It dates to the Lower Cretaceous period. It is Aptian in age and consists of sandstones, siltstones, marls and bituminous shales, deposited in a stratified lake. It is situated on a large granite plateau in the NE of Buryatia.[1] The formation is known for its numerous compression fossils of many varieties of insect found predominantly at the Baissa locality.[2] Insects are found in multiple beds throughout the succession, predomiantly in the finer grained facies, the preservation of insect fossils is variable between beds, with good preservation in marl and poor preservation in shale beds.[1]

Zaza Formation
Stratigraphic range: Aptian
TypeGeological formation
OverliesPaleozoic granite basement
ThicknessAround 80 metres at Baissa
PrimarySandstone, siltstone, marl, and bituminous shale
OtherConglomerate, limestone
Country Russia

See alsoEdit


  1. ^ a b Zherikhin, V.V., Mostovski, M.B., Vrsansky, P., Blagoderov, V.A. and Lukashevich, E.D. 1999. The unique Lower Cretaceous locality of Baissa and other contemporaneous insect-bearing sites in North and West Transbaikalia. Proceedings of the First Palaeoentomological Conference, Moscow, 1998. Bratislava: Amba Projects, pp. 185-192.
  2. ^ "Baissa (PIN collection 3064, bed 31) (Cretaceous of Russian Federation)". Retrieved 2020-01-26.
  • Vickers-Rich, Patricia; Rich, Thomas Hewett (1993). Wildlife of Gondwana. Reed. ISBN 0-7301-0315-3.