page_title: Santos Basin
section_title: V - Itamambuca Group (Cenozoic, upper post-salt sequence)
hierarchical_section_title: Santos Basin / Description / Stratigraphy / V - Itamambuca Group (Cenozoic, upper post-salt sequence)
caption_attribution_description: English: Coquina (shell rock). Сollected near Saki, the Crimea.
context_page_description: The Santos Basin is an approximately 352,000 square kilometres large mostly offshore sedimentary basin. It is located in the south Atlantic Ocean, some 300 kilometres southeast of Santos, Brazil. The basin is one of the Brazilian basins to have resulted from the break-up of Gondwana since the Early Cretaceous, where a sequence of rift basins formed on both sides of the South Atlantic; the Pelotas, Santos, Campos and Espírito Santo Basins in Brazil, and the Namibia, Kwanza and Congo Basins in southwestern Africa.
  Santos Basin is separated from the Campos Basin to the north by the Cabo Frio High and the Pelotas Basin in the south by the Florianópolis High and the northwestern boundary onshore is formed by the Serra Do Mar coastal range. The basin is known for its thick layers of salt that have formed structures in the subsurface due to halokinesis. The basin started forming in the Early Cretaceous on top of the Congo Craton as a rift basin. The rift stage of the basin evolution combined with the arid Aptian climate of the southern latitudes resulted in the deposition of evaporites in the Late Aptian, approximately 112 million years ago.
context_section_description: Itamambuca Group is 4,200 metres (13,800 ft) thick and includes four formations, Ponta Aguda, Marambaia, Iguape and Sepetiba.
  Ponta Aguda Formation
  The Ponta Aguda Formation is up to 2,200 metres (7,200 ft) thick and consists of conglomerates, coarse to fine-grained sandstones interbedded with siltstones and shales. The dominant facies are coarse to fine-grained quartzitic sandstones. They range from reddish to grey, usually with calcite cements. Intercalated are reddish to light grey claystones and siltstones. They represent a fluvial to shallow marine environment.
  Iguape Formation
  The Iguape Formation is 1,103 metres (3,619 ft) thick and consists of bioclastic calcarenites and calcirudites, containing bryozoa, echinoids, corals, foraminifera, fragmented shells, and algae remains. They are interbedded with grey-greenish clays, siltstones, marls and variegated grey fine-to-medium grained conglomerates. These facies are interbedded with and change laterally to the Marambaia Formation. The depositional environment is thought to be a marine carbonate platform, influenced by the arrival of alluvial clastics in the most proximal areas. Biostratigraphic data from planktonic foraminifera, calcareous nanofossils and palynomorphs indicate a Tertiary age.
  Marambaia Formation
  The Marambaia Formation is 261 metres (856 ft) thick and consists of grey shales and light grey marls interbedded with fine-grained turbiditic sandstones. 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.
  Sepetiba Formation (Pleistocene)
  The Sepetiba Formation is the uppermost formation in the Santos Basin. It has a variable thickness due to the proximal erosion of the uppermost part. The formation consists of whitish grey fine to coarse grained carbonitic sands. They are feldspar-rich, glauconitic coquinas consisting of bivalve fragments and foraminifera. The depositional environment is thought to be coastal.
  The stratigraphy following the classifications by Vieira 2007, Kiang Chang 2008 and Contreras 2011 is:
caption: The uppermost sedimentary layer is formed by coquinas (similar to this sample from Crimea in Europe); carbonitic sandstones composed of broken shells
exif: {"Image ImageDescription": "Coquina (shell rock). \u0421ollected near Saki, the Crimea.", "Image Make": "Canon", "Image Model": "Canon EOS 6D", "Image Orientation": "Horizontal (normal)", "Image XResolution": "300", "Image YResolution": "300", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "Adobe Photoshop CC 2015 (Windows)", "Image DateTime": "2015:09:11 14:49:30", "Image Artist": "Sergey Tarasenko", "Image ExifOffset": "308", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "978", "Thumbnail JPEGInterchangeFormatLength": "4168", "EXIF ExposureTime": "1/125", "EXIF FNumber": "14/5", "EXIF ExposureProgram": "Aperture Priority", "EXIF ISOSpeedRatings": "200", "EXIF SensitivityType": "Recommended Exposure Index", "EXIF RecommendedExposureIndex": "200", "EXIF ExifVersion": "0230", "EXIF DateTimeOriginal": "2015:09:11 14:11:45", "EXIF DateTimeDigitized": "2015:09:11 14:11:45", "EXIF ShutterSpeedValue": "870723/125000", "EXIF ApertureValue": "1485427/500000", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "3", "EXIF MeteringMode": "Pattern", "EXIF Flash": "Flash did not fire, compulsory flash mode", "EXIF FocalLength": "90", "EXIF SubSecTime": "07", "EXIF SubSecTimeOriginal": "07", "EXIF SubSecTimeDigitized": "07", "EXIF ColorSpace": "Uncalibrated", "EXIF ExifImageWidth": "2769", "EXIF ExifImageLength": "2000", "EXIF FocalPlaneXResolution": "1520", "EXIF FocalPlaneYResolution": "1520", "EXIF FocalPlaneResolutionUnit": "3", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Auto", "EXIF SceneCaptureType": "Standard", "EXIF BodySerialNumber": "032024008004", "EXIF LensSpecification": "[90, 90, 0/0, 0/0]", "EXIF LensModel": "90mm", "EXIF LensSerialNumber": "0000000000"}