Missão Velha Formation

The Missão Velha Formation is a late Jurassic geologic formation in northeastern Brazil's Araripe Basin where the states of Pernambuco, Piauí and Ceará come together. The formation is the middle stratigraphic unit of the Vale do Carirí Group, overlying the Brejo Santo Formation and overlain by the Abaiara Formation.

Missão Velha Formation
Stratigraphic range: Late Jurassic ~170–145 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Unit of	Vale do Carirí Group
Underlies	Abaiara Formation
Overlies	Breto Santo Formation
Thickness	100–200 m (330–660 ft)
Lithology
Primary	Sandstone
Location
Coordinates	7.3°S 39.1°W / -7.3; -39.1
Approximate paleocoordinates	7.1°S 6.5°W / -7.1; -6.5
Region	Pernambuco, Piauí & Ceará
Country	Brazil
Extent	Araripe Basin
Map of the Araripe Basin with the Missão Velha Formation in green

The formation comprises whitish fine-to-medium quartzose arenites, with subrounded to rounded grains, deposited in an alluvial fan environment during the syn-rift phase of the Araripe Basin.

The Missão Velha Formation has provided macrofossils of various genera of fish and reptiles as snakes, crocodylomorphs and turtles. Ichnofossils of dinosaurs were also discovered in the formation, as well as a tooth from an abelisaurid theropod.

Geology

Main article: Araripe Basin

Fossil content

The following fossils were reported from the formation:^[1]

• Fish
  • Parvodus rugianus^[2]
  • Planohybodus peterboroughensis^[2]
  • Planohybodus marki^[3]
  • Mawsonia cf. gigas^[2]
  • Acrodus sp.^[2]
  • Hybodus sp.^[2]
  • Lepidotes sp.^[2]
  • Neoceratodus sp.^[2]
  • Polyacrodus sp.^[2]
  • Vinctifer sp.^[2]
  • Lonchidiidae indet.^[2]
• Reptiles
  • Turtles
    • Pelomedusidae indet.^[2]
  • Dinosaurs
    • Sauropoda indet.^[2]
    • Theropoda indet.^[2]
    • Abelisauridae indet.^[4]
  • Loricata
    • Mesosuchia indet.^[2]
  • Snakes
    • Lacertilia indet.^[2]
• Amphibians
  • ?Amphibia indet.^[2]
• Ichnofossils
  • Carnosauria indet.^[5]
  • Ornithopoda indet.^[5]
  • Dinosauria indet.^[5]

See also

• Crato Formation
• Romualdo Formation