Belén Metamorphic Complex
| Belén Metamorphic Complex | |
|---|---|
| Stratigraphic range: Paleozoic | |
| Type | Complex |
| Underlies | Lupica Formation |
| Lithology | |
| Primary | Amphibolite,[1] orthogneiss,[1] serpentinite[1] |
| Other | Mica schist[1] |
| Location | |
| Region | Arica y Parinacota Region |
| Country | Chile |
The Belén Metamorphic Complex (Spanish: Complejo metamórfico Belén) is a group of metamorphic and igneous rocks that crops out in the western edge of the Altiplano plateau in the interior of northernmost Chile. [1] The rocks of the complex metamorphosed during the Early Paleozoic era but the original protoliths formed in the Proterozoic eon.[1][2] This make rocks of the Belén Metamorphic Complex the oldest rocks known in Chile.[1] To the west the rocks of the Belén Metamorphic Complex thrust along Chapiquiña-Belén fault over sediments of Cenozoic age including ignimbrites of the Oxaya Formation and rocks of Lupica Formation.[1][3] At their peak conditions of metamorphism rocks reached temperatures and pressures of 700 C and 7 kbar.[3] The timing of the metamorphism matches the age of the Famatinian orogeny in the Argentine Northwest.[3] Rocks of the Belén Metamorphic Complex were involved in one or more orogenies in the Early Paleozoic.[3]
Rocks of the complex include foliatied amphibolite, orthogneiss, serpentinite and lesser amounts of quartz-rich mica schist.[1][3]
The rocks of complex have experienced continuous exhuming during the last 15 million years as part of the ongoing Andean orogeny, with an apparent exhumation spurt 11 to 7 million years ago.[2]
References
[edit]- ^ a b c d e f g h i "Esquistos de Belén". Geositios (in Spanish). Retrieved 2023-01-12.
- ^ a b García, Marcelo; Aguilar, Germán; Rodríguez, María Pía; Metcalf, James (2022). "(U-Th)/He ages of Proterozoic-Paleozoic basement rocks from northern Chile (18-19° S) and implications on the Neogene uplift history of the Western Cordillera". Andean Geology. 49 (3): 313–326. doi:10.5027/andgeoV49n3-3402. S2CID 253148429.
- ^ a b c d e Hervé, Francisco; Faundez, Victor; Calderón, Mauricio; Massonee, Hans-joachim; Willner, Arne P. (2007). "2. Metamorphic and plutonic basement complexes". In Moreno, Teresa; Gibbons, Wes (eds.). Geology of Chile. Geological Society of London. pp. 5–25. ISBN 978-1-86239-219-9.
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