Jureia Formation
Stratigraphic range: Santonian- Maastrichtian ~86–66  Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Unit of	Frade Group
Underlies	Marambaia Formation
Overlies	Itanhaém Formation
Thickness	up to 2,000 m (6,600 ft)
Lithology
Primary	Shale
Other	Siltstone, sandstone
Location
Coordinates	26°6′S 43°43′W / 26.100°S 43.717°W / -26.100; -43.717
Region	Santos Basin, South Atlantic
Country	Brazil
Type section
Named for	Jureia-Itatins Ecological Station
Location of the Santos Basin

The Jureia Formation ( Portuguese: Formacão Jureia) is a geological formation of the Santos Basin offshore of the Brazilian states of Rio de Janeiro, São Paulo, Paraná and Santa Catarina. The predominantly shale with interbedded siltstones and fine sandstones formation dates to the Late Cretaceous period; Santonian- Maastrichtian epochs and has a maximum thickness of 2,000 metres (6,600 ft). The formation is a reservoir rock of the Merluza Field, the first discovery in the Santos Basin.

The formation is named after the Jureia-Itatins Ecological Station, São Paulo.

The Jureia Formation is 952 to 2,000 metres (3,123 to 6,562 ft) thick, ^[1] and includes a succession of clastics between the coarse facies of the Santos Formation in the western proximal part and the fine-grained clastics of the Itajai-Açu Formation in the eastern distal part of the Santos Basin. The formation is characterized by dark grey to greenish and brown shales, dark grey siltstones, fine-very fine sandstones and light ochre calcisilts. The depositional environment is thought to be of a marine platform setting as pro-delta facies on the shelf edge. ^[2] The age based on palynomorphs and calcareous nannofossils is Late Cretaceous ( Santonian- Maastrichtian). ^[3] Two new ostracod species were identified in the drilling cuttings of wells drilled into the Santonian- Campanian section, ?Afrocytheridea cretacea and Pelecocythere dinglei. ^[4]

The formation is the reservoir rock of the Merluza Field, the first discovery in 1979 of the Santos Basin. ^{[5] [6]}

• Campos Basin

• Clemente, Pilar (2013), Petroleum geology of the Campos and Santos basins, Lower Cretaceous Brazilian sector of the South Atlantic margin, Danmarks Tekniske Universitet, pp. 1–33, retrieved 2017-09-04
• Contreras, Jorham (2011), Seismo-stratigraphy and numerical basin modeling of the southern Brazilian continental margin (Campos, Santos, and Pelotas basins) (PhD thesis) (PDF), Ruprecht-Karls-Universität Heidelberg, pp. 1–171, retrieved 2017-09-04
• Kiang Chang, Hung; Assine, Mario Luis; Santos Corrêa, Fernando; Setsuo Tinen, Julio; Campane Vidal, Alexandre; Koike, Luzia (2008), "Sistemas petrolíferos e modelos de acumulação de hidrocarbonetos na Bacia de Santos" (PDF), Revista Brasileira de Geociências, 38: 29–46, doi: 10.25249/0375-7536.2008382S2946 (inactive 2024-07-08), retrieved 2017-09-04{{ citation}}: CS1 maint: DOI inactive as of July 2024 ( link)
• Piovesan, Enelise Katia; Trescastro Bergue, Cristianini; Fauth, Gerson (2010), "New ostracode species from the Upper Cretaceous of the Santos Basin, Brazil" (PDF), Revista Brasileira de Paleontologia, 13 (3): 175–180, doi: 10.4072/rbp.2010.3.02, retrieved 2017-09-04
• Vieira, Juliana (2007), Brazil Round 9 - Santos Basin (PDF), ANP, pp. 1–73, retrieved 2017-09-04 Archived 2017-02-03 at the Wayback Machine