| Guaratiba Group | |
|---|---|
| Stratigraphic range: Hauterivian-Early Aptian ~ | |
| Type | Group |
| Sub-units | Piçarras Fm., Itapema Fm., Barra Velha Fm. |
| Underlies | Ariri Formation |
| Overlies | Camboriú Formation |
| Thickness | up to 4,200 m (13,800 ft) |
| Lithology | |
| Primary | Limestone (coquina), marl, shale, siltstone |
| Other | Sandstone, conglomerate |
| Location | |
| Coordinates | 26°6′S 43°43′W / 26.100°S 43.717°W |
| Region | Santos Basin, South Atlantic |
| Country |  Brazil |
| Type section | |
| Named for | Guaratiba |
 Location of the Santos Basin | |
The Guaratiba Group (Portuguese: Grupo Guaratiba) is a geological group of the Santos Basin offshore of the Brazilian states of Rio de Janeiro, São Paulo, Paraná and Santa Catarina. The group forms the pre-salt layer in the petroleum-rich basin and hosts the biggest oil fields of Brazil, as Tupi, Júpiter and many more. The group contains, depending on the definition, three to four formations and dates to the Early Cretaceous period; Hauterivian to Early Aptian epochs. The total thickness of the group, representing the first phase of sedimentation after the break-up of Gondwana in the Santos Basin, is estimated at 4,200 metres (13,800 ft).