Pocho volcanic field is a
volcanic field
A volcanic field is an area of Earth's crust that is prone to localized volcanic activity. The type and number of volcanoes required to be called a "field" is not well-defined. Volcanic fields usually consist of clusters of up to 100 volcanoes ...
in
Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...
.
It is associated with a
crustal
lineament ''See also Line (geometry)''
A lineament is a linear feature in a landscape which is an expression of an underlying geological structure such as a fault. Typically a lineament will appear as a fault-aligned valley, a series of fault or fold-aligne ...
known as the Ojo de Agua Lineament.
It is located in the
Sierras de Cordoba mountain chain.
It formed during the late
Miocene
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 recen ...
, when a progressive shallowing of the
subducting Nazca Plate
The Nazca Plate or Nasca Plate, named after the Nazca region of southern Peru, is an oceanic tectonic plate in the eastern Pacific Ocean basin off the west coast of South America. The ongoing subduction, along the Peru–Chile Trench, of the Na ...
caused volcanic activity to retreat from the main Andes into the land behind the mountain chain.
This did result in a typical shallow slab chemistry of the Pocho rocks.
Volcanic activity at Pocho is dated about 4.7 +- 0.3 million years ago and took place over two cycles. Seismic activity in the area may indicate the presence of a residual
magma chamber however, which would also explain anomalous crustal seismic velocities in the area.
References
External links
Volcanoes of Argentina
Miocene volcanism
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