Guarujá Formation
Stratigraphic range: Early Albian ~113–108 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Type	Geological formation
Unit of	Camburi Group
Underlies	Itajaí-Açu Fm., Juréia Fm.
Overlies	Ariri Formation
Thickness	up to 2,500 m (8,200 ft)
Lithology
Primary	Limestone
Other	Marl
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	Guarujá
Location of the Santos Basin

The Guarujá Formation (Portuguese: Formacão Guarujá) 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 calcarenite formation with marls dates to the Early Cretaceous period; Early Albian epoch and has a maximum thickness of 2,500 metres (8,200 ft). The formation is the second-most important post-salt reservoir rock of the Santos Basin.

The formation is named after the city of Guarujá, São Paulo.

The Guarujá Formation is 832 to 2,500 metres (2,730 to 8,202 ft) thick,^[1] and consists of oolitic calcarenites, which laterally grade to greyish ochre and brownish grey calcilutites and grey marls. These facies are interbedded with the alluvial clastics of the Florianópolis Formation. The Guarujá name is restricted to the lowest limestone intercalation, previously named Lower Guarujá by Ojeda and Ahranha in Pereira and Feijó (1994). The microfacies indicate a tidal flat to shallow lagoon and open carbonate platform depositional environment. The age based on planktonic foraminifera and pollen is Early Albian.^[2]

The formation is the second-most important post-salt reservoir rock of the Santos Basin,^[3] after the Itajaí-Açu Formation.^[4][5]

• Campos Basin

• ANP (2014), Oil, natural gas and biofuels - Statistical Yearbook, ANP, pp. 1–73
• 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
• Juarez Feijó, Fávio (2013), "Santos Basin: 40 Years from Shallow to Deep to Ultra-Deep Water" (PDF), Search and Discovery, 10553: 1–49, 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 1 November 2024), retrieved 2017-09-04{{citation}}: CS1 maint: DOI inactive as of November 2024 (link)
• 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