Pebas Formation

Pebas Formation
Stratigraphic range: Miocene, Lower Aquitanian to Tortonian
Underlies Marañon Formation
Overlies Chambira Formation
Thickness Approx. 350 to 1074 m
Lithology
Primary siltstone, mudstone
Other coal/lignite
Location
Country Peru, Brazil, Colombia & Ecuador
Type section
Named for Pebas District

The Pebas Formation is a lithostratigraphic unit of Miocene age, found in western Amazonia. The formation extends over a million square kilometres, including parts of Brazil, Peru, Ecuador and Colombia.[1] It is interpreted as representing the deposits of a lake or series of lakes, formed within the foreland basin of the Andes mountain belt. It is known for its abundant fossil ostracods and molluscs and an unusually diverse group of crocodylians.[2]

References

  1. Wesselingh F.P., Hoorn M.C., Guerrero J., Räsänen M.E., Romero Pittmann L. & Salo J. (2006). "The stratigraphy and regional structure of Miocene deposits in western Amazonia (Peru, Colombia and Brazil), with implications for late Neogene landscape evolution". Scripta Geologica (133): 291–322.
  2. Salas-Gismondi R., Flynn J.J., Baby P., Tejada-Lara J.V., Wesselingh F.P. & Antoine P-O. (2015). "A Miocene hyperdiverse crocodylian community reveals peculiar trophic dynamics in proto-Amazonian mega-wetlands". Proceedings of the Royal Society B: Biological Sciences 282. doi:10.1098/rspb.2014.2490.