The Ucayali Peneplain is a large near-flat

erosion surface In geology and geomorphology, an erosion surface is a surface of rock or regolith that was formed by erosion and not by construction (e.g. lava flows, sediment deposition) nor fault displacement. Erosional surfaces within the stratigraphic reco ...

, a

peneplain 390px, Sketch of a hypothetical peneplain formation after an orogeny. In geomorphology and geology, a peneplain is a low-relief plain formed by protracted erosion. This is the definition in the broadest of terms, albeit with frequency the usage ...

, located in the

Amazon basin The Amazon basin is the part of South America drained by the Amazon River and its tributaries. The Amazon drainage basin covers an area of about , or about 35.5 percent of the South American continent. It is located in the countries of Bolivi ...

. The Ucayali Peneplain is largely buried by

sediment Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand an ...

s forming an

unconformity An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval o ...

. Its origin has been dated to the

Miocene epoch The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" ...

. The Peneplain was first described in 1948 in the

Contamana Contamana is a town in the Loreto Region in northeastern Peru. It is the capital of both Ucayali Province and Contamana District Contamana District is one of six Districts of Peru, districts of the province Ucayali Province, Ucayali in Peru. I ...

region of

Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = Seal (emblem), National seal , national_motto = "Fi ...

References

{{coord missing, Bolivia Amazon basin Amazon River Erosion landforms Landforms of Bolivia Plains of Brazil Landforms of Colombia Landforms of Peru Miocene South America Stratigraphy of Colombia Stratigraphy of Bolivia Stratigraphy of Brazil Stratigraphy of Peru Unconformities Planation surfaces