Spanish Plateau and Mountain Ranges: A Detailed Topography
The Southern Sub-Plateau
The southern sub-plateau is lower, with a height between 500-700m. It is divided into two plateaus separated by Toledo, which corresponds to the divide between the two rivers: the Tagus River to the north and the Guadiana River to the south. This sub-plateau is inclined toward the Atlantic.
Units Related to the Plateau
- Ancient Paleozoic base reaching the sea: León, Zamora, and Extremadura.
- Sedimentary basins with sedimentary rock materials.
- Interior plateau ranges formed during the Alpine folding: the Montes de Toledo and the Central System.
- Edges of the mountain plateau, surrounding the entire plateau within the western part.
The Interior Plateau Mountain Ranges
These are the Central System or the mountains of Toledo. They are made of old materials, such as granite and slate, and currently have rounded shapes due to erosion.
The Central System divides the central plateau and consists of two different ranges from west to east: the Somosierra (north of Guadalajara), the Guadarrama Mountains (north of Madrid), Sierra de Gredos (Cáceres, Ávila), Sierra de Gata (Cáceres and Salamanca), and Serra da Estrela (Portugal). The maximum height is found in Gredos (peak Almanzor).
The Toledo mountains divide the southern plateau into two parts, between the basin of the Tagus and the Guadiana basin. The heights are modest, with the highest peak not reaching 1400m.
The Edges of the Mountainous Plateau
These include:
- The Galaico-Leonese Massif
- The Cantabrian Mountains
- The Iberian Cordillera
The Galaico-Leonese Massif is in the northwest of the Iberian Peninsula, covering an area of 200km². The average height is not very high, around 500m, but there are some mountain areas, and in the mountains of León, there are peaks that surpass 2000 meters, such as Teleno or Trevinca. The massif is a fragment of the oldest relief of the peninsula, much eroded. It is covered by vegetation, with practically no peaks due to the vegetation.
The Cantabrian Mountains are a linear chain parallel to the Cantabrian Sea, with a fairly sharp profile. We can distinguish two main parts: the western and eastern parts. The western part, corresponding to the Asturias area, is rich in coal, with some significant heights that hinder communication between Asturias and the plateau. In the eastern part, the peaks lose altitude, and the materials are not hard but calcareous. Here are the highest peaks, the Picos de Europa (2648 meters).
The Iberian Cordillera limits the Iberian plateau from northwest to southeast. In this area, there is a mixture of materials from the Hercynian and secondary periods. There are two sectors. The northern sector has a range of mountains reaching over 2000m, such as the Sierra de la Demanda, the Picos de Urbión, and the Moncayo Massif. The southern sector can be defined as a maze of mountains, both indoor and outdoor. The indoor mountains include the Serranía de Cuenca, the Ronda Basin, and the Sierra de Albarracín, while the outdoor mountains include the Jabalambre, the Sierra de Gúdar, and the Sierra de Espadán.
The Sierra Morena is the southern edge of the plateau, separating the plateau from the Guadalquivir depression. It presents great heights when viewed from Andalusia, while from La Mancha, it presents very modest altitudes. It is called Sierra Morena due to the darker color of the rocks. There are abundant mines of all types: mercury, copper, and coal.
Mountains Outside the Plateau
The Pyrenees
The Pyrenees are a mountain range oriented east to west, approximately 440km long, from the Bay of Biscay to Cap de Creus. The Pyrenees separate the peninsula from the rest of Europe. They can be divided into two sections: the central or axial Pyrenees and the Pyrenean foothills.
The Axial Pyrenees have the greatest heights, such as Aneto (3404m), the Maladeta Massif, Mont Perdu, and the Pica d’Estats, all over 3000m. The range is composed of old materials and Hercynian folding. This is the only part of the Pyrenees where there are still some glaciers.
The foothills of the Pyrenees are of more modest height and rounded forms. The Spanish side of the mountain foothills has two parallel ranges, one indoor and one outdoor. Between these two, we find the average Pyrenean depression. The foothills are formed by calcareous materials.
Catalan Coastal Mountain Range
The Pyrenees are separated by a series of faults and volcanic reliefs. There are two mountain ranges parallel to the coast, separated by a rift.
The littoral range is the nearest to the coast, with very modest hills, while the pre-coastal mountain range has more elevation. In the northern part of the coastal mountain ranges, Paleozoic material dominates, while in the south, limestone dominates.
Cordillera Mountain Range
This range was also formed during the Alpine folding, like the Pyrenees. It has two parts: the Penibética and Subbética, separated by depressions. The Penibética range is the closest to the coast, dominated by very old materials. Here is the maximum height of the Iberian Peninsula (Sierra Nevada, with Mulhacén). The Subbética Mountains are parallel to the Penibética but further inland. The materials are also old, with samples of limestone. The Subbética system continues into the Mediterranean and to the islands.
Depressions
These include the valley of the Guadalquivir and the Ebro, which in the past were occupied by the sea. The reliefs are typical of tabular depressions.
Ebro Depression
This depression is wedged between the foothills, the Catalan Coastal Ranges, and the Iberian Cordillera, forming a triangle. It is approximately 380km long and 150km wide. For a long time, this depression was covered by the sea, but the sea closed, turning into a lake. The Ebro River runs through this depression and is a major irrigation area. To reach the sea, it must cross the Catalan coastal mountain range, forming a delta.
Guadalquivir River Depression
This depression is marked by the Sierra Morena to the north and the Cordillera to the south. It is open to the sea, with a triangular shape, 330 km long and 200 km wide. It was also open to the sea, and rivers filled it with deposits. The Guadalquivir River runs through this depression, quite close to the Sierra Morena. This requires that the rivers coming from Sierra Morena have a large drop, dragging many materials. The river empties into the Gulf of Cádiz, which is an area of extensive wetlands. In these wetlands, rice is cultivated, and there is a series of dunes, some reaching 90 feet in height. The Doñana National Park is located here.