![Nevado El Plomo, Cerro Juncal to the South](https://upload.wikimedia.org/wikipedia/commons/3/3f/Nevado_El_Plomo%2C_Cerro_Juncal_to_the_South.jpg)
Principal Cordillera ( es, Cordillera Principal) is the
Andean mountain range that makes up the boundary between Central Chile and neighbouring areas of Argentina. It is also a
continental divide
A continental divide is a drainage divide on a continent such that the drainage basin on one side of the divide feeds into one ocean or sea, and the basin on the other side either feeds into a different ocean or sea, or else is endorheic, not ...
between the Atlantic and the Pacific watersheds.
It extends in a north–south direction in the Argentine provinces of
La Rioja
La Rioja () is an autonomous community and province in Spain, in the north of the Iberian Peninsula. Its capital is Logroño. Other cities and towns in the province include Calahorra, Arnedo, Alfaro, Haro, Santo Domingo de la Calzada, and Nà ...
,
San Juan San Juan, Spanish for Saint John, may refer to:
Places Argentina
* San Juan Province, Argentina
* San Juan, Argentina, the capital of that province
* San Juan, Salta, a village in Iruya, Salta Province
* San Juan (Buenos Aires Underground), ...
and
Mendoza and the Chilean regions of
ValparaÃso
ValparaÃso (; ) is a major city, seaport, naval base, and educational centre in the commune of ValparaÃso, Chile. "Greater ValparaÃso" is the second largest metropolitan area in the country. ValparaÃso is located about northwest of Santiago ...
,
Santiago
Santiago (, ; ), also known as Santiago de Chile, is the capital and largest city of Chile as well as one of the largest cities in the Americas. It is the center of Chile's most densely populated region, the Santiago Metropolitan Region, whose ...
,
O'Higgins and
Maule. To the east of the Principal Cordillera lies the
Frontal Cordillera
The Frontal Cordillera ( es, Cordillera Frontal) is a mountain range in western Argentina that forms part of the Andes. It extends in a north–south direction in the provinces of La Rioja
La Rioja () is an autonomous community and province i ...
which is fully in Argentina.
[ ]Aconcagua
Aconcagua () is a mountain in the Principal Cordillera of the Andes mountain range, in Mendoza Province, Argentina. It is the List of highest mountains on Earth, highest mountain in the Americas, the highest outside Asia, and the highest in the ...
, the tallest mountain outside Asia, lies in the Principal Cordillera.[
]
Geological history
What is today the Principal Cordillera was once a depression that accumulated sediments.[Charrier ''et al''. 2006, pp. 93–94.] Lava flows from ancient volcanoes also found their way to the depression. Today these sequences of sedimentary
Sedimentary rocks are types of rock (geology), rock that are formed by the accumulation or deposition of mineral or organic matter, organic particles at Earth#Surface, Earth's surface, followed by cementation (geology), cementation. Sedimentati ...
and volcanic rock can be observed high in the Andes, implying their basin was closed and uplifted by tectonic inversion
In structural geology inversion or basin inversion relates to the relative uplift of a sedimentary basin or similar structure as a result of crustal shortening. This normally excludes uplift developed in the footwalls of later extensional faul ...
. The said rocks are grouped in the Abanico
Abanico may refer to:
*''Abanico'', the Spanish word for hand fan
*'' Abanico (music)'', a drum roll and rimshot played on timbales to introduce a new section
*'' Abanico ibérico'', a Spanish cut of pork
See also
* Abaniko
An abaniko (from th ...
and Farellones Formation.[ Tectonic inversion took place 21 to 16 million years (Ma) ago,][ yet the associated pulse of uplift continued until about 8 Ma ago.] The Miocene continental divide
A continental divide is a drainage divide on a continent such that the drainage basin on one side of the divide feeds into one ocean or sea, and the basin on the other side either feeds into a different ocean or sea, or else is endorheic, not ...
was about 20 km to the west of the modern water divide that makes up the Argentina–Chile border
The Argentina–Chile border is the longest international border of South America and the third longest in the world after the Canada–United States border and the Kazakhstan–Russia border. With a length of , it separates Argentina from Chile ...
.[ Subsequent ]river incision
River incision is the narrow erosion caused by a river or stream that is far from its base level. River incision is common after tectonic uplift of the landscape. Incision by multiple rivers result in a dissected landscape, for example a dissected ...
shifted the divide to the east leaving old flattish surfaces hanging.[ Compression and uplift in this part of the Andes has continued into the present.] The Principal Cordillera had risen to heights that allowed for the development of valley glacier
A valley is an elongated low area often running between hills or mountains, which will typically contain a river or stream running from one end to the other. Most valleys are formed by erosion of the land surface by rivers or streams ove ...
s about 1 Ma ago.[
]
References
;Bibliography
*
Argentina–Chile border
Geography of La Rioja Province, Argentina
Geography of San Juan Province, Argentina
Mountain ranges of Argentina
Mountain ranges of Chile
Geography of Maule Region
Geography of Mendoza Province
Geography of O'Higgins Region
Geography of Santiago Metropolitan Region
Geography of Santiago, Chile
Geography of ValparaÃso Region
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