Cordillera Oriental


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Related to Cordillera Oriental: Cordillera Occidental, Cordillera Central

Cordillera Oriental

 

(also Eastern Cordillera of the Andes), mountain ranges which form the eastern fringes of the Andes mountain system.

In the Central Andean countries the term “Cordillera Oriental” has been applied to several mountain ranges, resulting in different readings on maps and in literature; it has been most firmly established as the name of mountains in the Andes of Colombia and Ecuador. Orographically the Cordillera Oriental is not a single mountain range, but structurally, along with the Cordillera Central, it does form a unified system of anticlinoria with Hercynian cores.

The Cordillera Oriental of Colombia extends from 1° 30’ to 9° N latitude as a large mountain range reaching an altitude of 5,493 m (Ritacuva). It declines sharply in the east to the level of the plains of the Orinoco River and the western edge of the Guiana Highlands and in the west to the basin of the Magdalena River. Extensive intermontane plains and hollows at altitudes of 2,500 to 3,500 m are characteristic of the central section (which is the broadest, with widths extending to 270 km). The range abruptly narrows and descends in the north (where it is called the Sierra de Perijá) and the south, where it becomes part of the Cordillera Central. It continues into Ecuador, where it is called the Cordillera Oriental or the Cordillera Real. In separate spurs and massifs the Cordillera Oriental of Ecuador descends in the east to the Amazon Basin; in front of the western slopes lie the high intermontane “basins,” or depressions. Extinct and active volcanoes that have formed peaks as high as 5,897 m (the Cotopaxi volcano) are built up along the fracture lines. In the south, between 4° and 6° S latitude, the Cordillera Oriental is not orographically expressed. Its structures continue further into the Cordillera Central of northern Peru, the Cordilleras of southeastern Peru, and the Cordillera Real of Bolivia.

In northern Peru the term Cordillera Oriental is also applied to the Sub-Andean Cordilleras, folded mountain ranges of moderate altitude that frame the western Amazon Basin (5°-10° S latitude) and the eastern chains of Bolivia, which border upon the plains of Beni-Mamore (15°-19° S latitude) at an elevation to 4,051 m.

Throughout their entire length the eastern slopes of the Cordillera Oriental face the wind (with precipitation ranging from 4,000 to 5,000 mm annually) and are deeply dissected by rivers and covered by evergreen forests (mountain tropical) with precisely delineated altitude zones. Only on the more arid northern and southern extremities and the western slopes are there mixed deciduous and evergreen forests and thin-forest areas. The snow line is located at an altitude of 4,400 to 5,000 m.

E. N. LUKASHOVA

References in periodicals archive ?
Estratigrafia, procedencia, subsidencia y exhumacion de las unidades paleogenas en el Sinclinal de Usme, sur de la zona axial de la Cordillera Oriental, Geologia Colombiana.
Dendrograma de similitud floristica entre bosques subandinos y de piedemonte de la vertiente orinoquense de la Cordillera Oriental de los Andes en Colombia, considernado datos de abundancia (indice de Bray-Curtis).
Adicionalmente, se considera la existencia de una relacion genetica de dicha zona transversal con estructuras profundas como la Falla de Soapaga, siendo un modelo concordante con aquellos que postulan movimientos en rumbo asociados a la deformacion de la cubierta sedimentaria durante el acortamiento de la Cordillera Oriental (FIGURA 2).
El area pertenece al piso zoogeografico Altoandino (Albuja et al., 2012) y ecosistema Bosque siempreverde montano alto del sur de la Cordillera Oriental de los Andes (Baez et al., 2013b).
Los estudios anteriores han llevado a que algunos autores consideren la hipotesis de una posible migracion regional de hidrocarburos de la Cordillera Oriental hacia la los Llanos Orientales como una forma de explicar el origen de los crudos pesados en el borde llanero y regiones circunvecinas (ANH, 2010; Bachu et al., 1995).
It has never been reported again since its original description, based on a female from a place called Salto (perhaps a waterfall) on the slopes of the volcano Antisana, also on the Cordillera Oriental, at 10,000 feet (around 3000 m).
El incremento de suelo promedio es de 0,65 mm [ano.sup.-1], superior al encontrado por Kuhry (1988) en las turberas del paramo de Pena Negra en la cordillera oriental de Colombia, con valor promedio de 0,26 mm [ano.sup.-1], inferior al registrado por Parra et al.
Ubicado en la region Centro Oriente de Colombia, sobre la Cordillera Oriental del Macizo Andino se encuentra el municipio de Santa Maria a 04[grados]51'48"N y 73[grados]16'04"0 (Fig.
La nueva subespecie, Catasticta ctemene pitalito n.ssp, habita la Cordillera Oriental, en los departamentos del Meta, Huila y Cauca (bota caucana), en la vertiente occidental de la Cordillera Oriental, hacia el rio Magdalena entre 1800 y 2100 m.
El area de estudio corresponde a la cordillera oriental con rasgos geomorfologicos como glaciares y periglaciares de altas cumbres, con laderas pronunciadas.
Across the Andes, a narrow band of increased 925 hPa height is seen across western Peru, likely reflecting the influence of the Cordillera Oriental (Figure 6(a)).
It is intersected by the Tropic of Capricorn, and presents a highly diverse and heterogeneous territory, containing several ecological belts and ecosystems as a result of its steep altitudinal gradient (between 300 and 6,200 m asl), and extending across four major geological units that cross the territory from north to south: the puna--a raised plain standing at an altitude of over 3,700 m asl-, the Cordillera Oriental range, the sub-Andean mountain ranges, and the Santa Barbara mountains (RAMOS, 1999).