Bukachacha Formation
Stratigraphic range: Barremian ~129–125 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Type	Geological formation
Lithology
Primary	Mudstone
Other	Tuff
Location
Coordinates	53°00′N 116°54′E / 53.0°N 116.9°E / 53.0; 116.9
Approximate paleocoordinates	56°42′N 114°54′E / 56.7°N 114.9°E / 56.7; 114.9
Region	Zabaykalsky Krai
Country	Russia
Type section
Named for	Bukachacha
Bukachacha Formation (Russia)

The Bukachacha Formation is a geological formation in Zabaykalsky Krai, Russia dating to the Early Cretaceous (Barremian). The tuffaceous mudstones of the formation were deposited in a lacustrine environment.

The formation has provided fossil insects:^[1]

• Coleoptera
  • Coptoclavidae
    • Stygeonectes jurassicus^[2]
• Trichoptera
  • Phryganeidae
    • Proagrypnia sp.^[3]
• Ephemerida
  • Hexagenitidae
    • Ephemeropsis trisetalis^[4]

• List of fossiliferous stratigraphic units in Russia
• Batylykh Formation, contemporaneous fossiliferous formation of Buryatia

• Sukatsheva, I.D (2016), "The family Phryganeidae (Insecta, Trichoptera) from the Mesozoic and Cenozoic of Asia (with a brief worldwide overview of the fossil caddisfly fauna)", Paleontological Journal, 50 (4): 396–405, Bibcode:2016PalJ...50..396S, doi:10.1134/S0031030116040134, retrieved 2020-07-07
• Ponomarenko, A.G (1990), "Beetles, Scarabaeida, in Pozdne-Mezozoyskie Nasekomye Vostochnogo Zabaykal'ya", A.P. Rasnitsyn (Ed.), Akademiya Nauk SSSR, Trudy Paleontologicheskogo Instituta, 239: 39–82
• Sinitshenkova, N.D (1990), "Mayflies. Ephemerida, in Pozdne-Mezozoyskie Nasekomye Vostochnogo Zabaykal'ya", A. P. Rasnitsyn (Ed.), Akademiya Nauk SSSR, Trudy Paleontologicheskogo Instituta, 239: 14–20