Landform Evolution: Mountain Ranges, Erosion, and Coastal Features
R. jurásico
This landform can form in young mountain ranges. It consists of folds alternating between anticlines and synclines. Anticlines in the water create erosion valleys perpendicular to the summit (cluses) and parallel valleys (combos). Once erosion occurs, it empties fast, and former synclinal valleys are lifted (syncline hook). The erosion of the anticline valley exposes the anticline, and the cycle begins again.
R. apalachense
This landform forms covering a mountainous area that has been razed and flattened by erosion. It creates a relief formed by alternating ridges and valleys, each formed by hard and soft strata, respectively.
R. horizontal
Here, rivers open valleys separated by broad platforms, called moors. They have a crest formed by concave strata. The flanks are hard and erode the mountains, eventually becoming witness hills and antecerros.
R. sloping hill or state
This is distinguished by a hard dorsal area on its back, formed by the inclined stratum, and a cornice with a strong decrease in slope. Erosion leads to witness hills and antecerros.
Interior Sedimentary Basins Plateau
These include the northern sub-plateau (which is the highest and almost entirely enclosed by mountains) and the southern sub-plateau (which is lower, rugged in its middle, and opens to the Atlantic Ocean). These basins were formed in the Tertiary orogeny as a result of the Alpine watershed. They initially constituted lakes, and then filled with tertiary materials: soft materials (clay, plaster, sand) at the bottom and hard materials (limestone) at the top. All this caused a relief to stop (flat, raised surfaces formed by structural strata), plains (soft, wavy lowlands where clay and limestone outcrops), and slopes (areas between the stop and plains).
Cantabrian Range
This range has two well-differentiated sectors:
- Western Sector (Asturian Massif): Formed in the Tertiary period by the uplift of this sector during the Alpine orogenesis. Its materials are Paleozoic. At its eastern extreme, there is a huge limestone outcrop, the Picos de Europa. Its western extreme exhibits Apalachense relief.
- Cantabrian Sector: Formed in the Tertiary period by the folding of secondary material deposited by the sea on the edge of the Meseta. These materials are primarily limestone.
Atlantic Coast
Within this area, we can distinguish the Cantabrian coast, the Galician Rías, and the Andalusian Atlantic coast:
- Cantabrian Coast: This coast is rectilinear. Its major features are cliffs and shallow rias, in addition to short sandy beaches and tombolos.
- Galician Rías: These result from the invasion by the sea of river valleys in the numerous open fractures of the Galaico Massif. The sea can penetrate these valleys up to 25 or 35 km inland.
- Andalusian Atlantic Coast: The principal feature here is the marsh (such as those formed at the mouth of the Guadalquivir), along with coastal dune fields like those of Doñana.
Canary Coasts
These coasts have been renovated on numerous occasions as a result of volcanic eruptions. Cliffs and beaches predominate. Large cliffs (100-500m) are characteristic of ancient massifs, while those of minor height (70-100m) are based on recent eruptions. In the western islands, there are stretches of coastal platform, while in the eastern islands, the increased width of this platform results in sandy beaches.