Marambaia Formation
Stratigraphic range: Paleocene- Pliocene ~65–2.6  Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Unit of	Itamambuca Group
Underlies	Sepetiba Formation
Overlies	Itajaí-Açu Fm., Juréia Fm.
Thickness	up to 2,700 m (8,900 ft)
Lithology
Primary	Shale, marl
Other	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	Restinga da Marambaia
Location of the Santos Basin

The Marambaia Formation ( Portuguese: Formacão Marambaia) 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 and marl formation dates to the Tertiary period and has a maximum thickness of 2,700 metres (8,900 ft). The formation is a seal and reservoir rock of the Atlanta and Oliva Fields in the Santos Basin.

The formation is named after Restinga da Marambaia, Rio de Janeiro.

The Marambaia Formation is between 261 and 2,000 metres (856 and 6,562 ft) thick, ^[1] and consists of grey shales and light grey marls interbedded with fine-grained turbiditic sandstones. The Marambaia Formation is the deeper lateral equivalent of the Iguape Formation. This formation in places can be found cropping out at sea bottom. The depositional environment is thought to be talus and open marine basin. Biostratigraphic data indicate a Tertiary age. ^[2]

The formation is a seal, ^[3] and reservoir rock in the Atlanta and Oliva Fields of the Santos Basin. ^{[4] [5]}

• 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)
• Vieira, Juliana (2007), Brazil Round 9 - Santos Basin (PDF), ANP, pp. 1–73, retrieved 2017-09-04