The Sunsás orogeny was an ancient

orogeny Orogeny () is a mountain-mountain formation, building process that takes place at a convergent boundary, convergent plate margin when plate motion compresses the margin. An or develops as the compressed plate crumples and is tectonic uplift, u ...

active during the Late Paleoproterozoic and

Mesoproterozoic The Mesoproterozoic Era is a geologic era that occurred from . The Mesoproterozoic was the first era of Earth's history for which a fairly definitive geological record survives. Continents existed during the preceding era (the Paleoproterozoic ...

and currently preserved as the Sunsás orogen in the Amazonian Craton in

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

. About 85% of the orogen is covered by

Phanerozoic The Phanerozoic is the current and the latest of the four eon (geology), geologic eons in the Earth's geologic time scale, covering the time period from 538.8 million years ago to the present. It is the eon during which abundant animal and ...

sediments. Among the remaining 15% of the orogen, which is exposed at surface, the best

outcrop An outcrop or rocky outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth and other terrestrial planets. Features Outcrops do not cover the majority of the Earth's land surface because in most p ...

s lie around the Bolivia-Brazil border. It is thought that the original orogen once spanned an area from Venezuela to Argentina and Paraguay. The western and southeastern fringes of the Sunsás orogen have been incorporated into the Andean orogeny and the Brasiliano orogeny respectively. The Sunsás orogeny was active during four separate phases: *Santa Helena orogeny, 1465–1427 Ma (million years ago) *Candeias orogeny, 1371–1319 Ma *San Andrés orogeny, ca. 1275 Ma *Nova Brasilândia orogeny, 1180–1110 Ma

References

Orogenies of South America Geology of Colombia Geology of Ecuador Geology of Bolivia Geology of Brazil Geology of Peru Mesoproterozoic orogenies Precambrian South America {{orogeny-stub