Coyhaique, in the middle of geological processes

24 April, 2017 0
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The main attraction of this city lies in their geography and the geomorphology of the principal geological structure. This part of Chile is characterized by glacial relief, with abrupt topography and a hydrographic system enriched by lake basins and numerous glaciers that flow into the Pacific Ocean.

The Patagonian Andes comprise a relatively low mountain belt, which bears witness of processes spanning from late Paleozoic to present. The average height is 900[m] and the highest mountain call San Valentin has 3900[m] of altitude approximately. San Valentin is the highest peak in the Chilean Patagonia and is between the General Carrera lake and San Rafael Lake. The backbone of the Patagonian Andes is the Mesozoic to Cenozoic Southern Patagonian batholith (SPB) whose earliest components intrude into low grade metamorphic complexes that crop out West and East of the continuous batholithic belt.

Andean magmatism is well developed in the foreland in two region, one of these is where the city of Coyhaique is located (between ~41°S and 44°S), where Paleocegene and Miocene andesitic to rhyolitic sequences, Eocene alkaline basalts and the extensive Late Oligocene to Miocene mafic plateau flows associated with the Mesetas de Somun Cura and Canquel occur.

The surprising shape of this place is controlled by the main structural factors: the union of three tectonic plates and the subduction of the Ridge of Chile.

The subduction between South American plate and Nazca plate has two main periods, between late Paleozoic-early Mesozoic and Jurassic to Present. The union of these two plates plus the Antarctic plate is called Triple Junction.

After the collision of the Chilean Ridge with the South American plate, the Triple Junction has migrated from south to north and is currently located in the peninsula of Taitao, near ~47°S. From ~38°S southward, the modern volcanic arc overlaps with the >900 km long Liquiñe-Ofqui Fault system, which has had dextral displacement since at least the Early Miocene.

In short, Coyhaique and its surroundings show all the complex geological processes that gave rise to the forms we see today, surprising all those who visit this southern part of Chile.

Come and meet Coyhaique in #astrobio2017, you will be surprised!

Reference:

Bell, C. M., & Suárez, M. (2000). The Rıo Lácteo Formation of southern Chile. Late paleozoic orogeny in the Andes of southernmost South America. Journal of South American Earth Sciences, 13(1), 133-145.

Hervé, F., Calderón, M., & Faúndez, V. (2008). The metamorphic complexes of the Patagonian and Fuegian Andes. Geologica Acta, 6(1), 43-53.

Scalabrino, B., Lagabrielle, Y., Malavieille, J., Dominguez, S., Melnick, D., Espinoza, F., … & Rossello, E. (2010). A morphotectonic analysis of central Patagonian Cordillera: Negative inversion of the Andean belt over a buried spreading center?. Tectonics, 29(2).


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