Major Relief Units of the Iberian Peninsula

Posted on Aug 5, 2024 in Geology

Submeseta North

  • Occupied by the Duero basin
  • High altitude (700 m)
  • Flat relief
  • Hercynian Morphostructure:
    • Paleozoic rocks in the west
    • Tertiary calcareous sediments in the east
    • Clays eroded from surrounding mountains
  • Landforms: moors, hills, plains, peneplain

Central System

  • Great line of mountains in NE-SW direction
  • Length: 400 km
  • Raised area within the Paleozoic base
  • Uplifted blocks (saws) and hollow blocks (valles)
  • Hard materials
  • Soft peaks
  • Glacial modeling in highest mountains

Submeseta South

  • Altitude: 600-700 m
  • Plain relief
  • Toledo Mountains divide the basins of the Tagus and Guadiana
  • Areas based on origin, training, and materials:
    • Paramere: limestone layer resists erosion, forming tables, hills, and plains
    • Campinas: wide valleys with terraces
    • Mancha-Plain: largest horizontal surface in the country
    • Campo de Calatrava: volcanic relief
    • Peneplain Extremadura: altitudes 300-500 m

Montes de Toledo

  • Mountainous alienation
  • Length: 200 km
  • Series of blocks erected in the southern sub-plateau
  • Slope smoothed by a ramp

Montes de Leon

  • Mountainous elevation in the northwest corner of the northern sub-plateau
  • Highest mountains exceed 2000 m
  • Made of hard rocks
  • Horst with soft peaks

Galician Massif

  • Ancient mountain range
  • Average altitude: 500 m
  • Located at the northwestern tip of the peninsula
  • Soft embossed flattened peaks
  • Deep valleys
  • Cut coastline

Cantabrian Mountains

  • Mountain barrier
  • Top line: 2000-2500 m
  • Runs parallel to the coast for 400 km
  • Two sectors:
    • Western or Asturian Massif: extension of the Galician Massif
    • Mountain East: typical alpine relief

Iberian System

  • Northeastern boundary of the Paleozoic socket
  • Length: 400 km
  • Width: 100 km
  • Areas:
    • Northwest sector: less thick sediment, erosion has brought forth the socket
    • Central part: Great Trench Calatayud, filled by Tertiary and Quaternary sediments
    • South and east sector: mountains formed by folding of sedimentary rocks

Sierra Morena

  • Rectilinear step
  • Length: 400 km
  • Gap between the plateau and the Guadalquivir valley
  • Rivers have cut deep gorges

Pyrenees

  • Great range
  • Length: 400 km
  • Two parts:
    • Axial-Pyrenees: central area, greatest heights
    • Pre-Pyrenees: indoor and outdoor ranges separated by a median depression
  • Jagged peaks
  • Asymmetric mountain range
  • Strong fluvial erosion
  • Only active glacier
  • Volcanic relief
  • Karst phenomena in limestone areas

Ebro Depression

  • Large triangular basin
  • Altitude: mostly below 500 m
  • River Ebro flows through it
  • Relief modeling conditioned by:
    • Variety of sedimentary rocks
    • Wind and river erosion

Basque Mountains

  • Set of hills
  • Link between the Cantabrian Mountains and the Pyrenees

Catalan Coastal Mountain Range

  • System of mountain ranges parallel to the Mediterranean coast
  • Length: 250 km
  • Three parallel ranges:
    • Coastal mountain range: 100 km long, 600 m high
    • Littoral depression: rift valley
    • Littoral Cordillera: 250 km long, higher ranges (e.g., Montseny massif)

Betic Cordilleras

  • Set of ranges
  • Length: 600 km
  • Different heights and structures
  • European alpine ridges
  • Units of relief:
    • Subbética ridges
    • Intrabética
    • Penibética
    • Depression

Depression Guadalquivir

  • Flat expanse
  • Open triangular shape
  • No outstanding accidents
  • Average altitude: very low
  • Marine sedimentation: homogeneous materials
  • Relief features: terraces, low hills, clays

Geomorphological Evolution

  • End of primary Hercynian orogeny:
    • Seas covered the original core of the peninsula
    • Mountains emerged, forming the Iberian Massif (core of today’s central plateau)
  • Eastern side of the massif submerged and covered by sedimentary rocks
  • Land surface area destroyed by erosion
  • Beginning of Tertiary Alpine orogeny:
    • Shock of Eurasian and African tectonic plates
    • Uplift of Pyrenees and Betis systems
    • Pressure caused formation of Central System and Montes de Toledo
    • Depressions appeared (Guadalquivir and Ebro)
  • Late Tertiary:
    • Plateau swung westward
    • Current drainage network established
  • Quaternary:
    • Glacial action affected major mountain ranges

Relief-Climate Relationship

  • Periphery of the relief influenced by climate
  • Influence of the sea in the interior is complicated
  • Remote mountains (e.g., Montes Vascos, Cordillera Cantabrian, Galaico Massif, Sierra Morena, Sistema Iberico, Cordillera and Catalan coast) prevent sea influence
  • Interior climate is very dry, especially in the south
  • High average altitude varies temperature and humidity conditions
  • Westerly winds dominate, moisturizing and softening air masses
  • Wet and cold areas in the northwest
  • Warmer and drier areas in the southeast