Geological Evolution and Climate Zones of the Iberian Peninsula

Geological History of the Iberian Peninsula

The Precambrian Era

On a global scale, all landmasses formed a single continent, Rodinia, later called Pangea I.

The Paleozoic Era

Two large plates separated by the Tethys Sea existed. There were two major orogenies: the Caledonian Orogeny and the Hercynian Orogeny. The newly formed basement, called the Hesperian Massif, occupied and controlled much of the western peninsula. To the northeast of the Hesperian Massif, the Ebro and Catalano-Balearic massifs occur. To the southeast, the Bético-Rifeño Massif appears solid.

The Mesozoic Era

Epeirogenic movements were produced by the slow rise and fall of the Earth's crust, featuring phases of marine transgressions and regression stages.

The Cenozoic Era (Tertiary Period)

• The Alpine ranges (Pyrenees and Béticas) increased in size.
• The Alpine, Béticas, and Ebro depressions opened.
• The old basement of the Hesperian Massif was broken and fractured into blocks.
• The edges of the Hesperian Massif were elevated and formed a mountain wall: the Galaico-Leonese Massif, the Cantabrian Cordillera, Sierra Morena, and the Iberian System.
• Pockets of volcanic activity emerged: Cape Gata, Campo de Calatrava.
• The Canary archipelago originated in the Miocene.

The Cenozoic Era (Quaternary Period)

The alternating glacial climatic phases of intense cold and temperate interglacial stages affected the peninsular mountain reliefs. In this period, the hydrographic network was established. Climate changes caused the rise and fall of sea level and changes in shorelines.

Spanish Climatic Domains

Oceanic Climate

Pure Oceanic

Location: North Atlantic coast and Cantabrian. Characteristics: Cool summers, mild winters; thermal amplitude (AT) from 10 to 12 °C. Abundant and regular rainfall (TPA > 1000 mm).

Oceanic Transition

Location: Galicia and narrow interior south of the pure oceanic zone. Characteristics: Hotter summers and colder winters than the pure oceanic zone (AT 12 to 15 °C). Precipitation somewhat less, with 1 or more dry months (TPA ~ 1000 mm).

Mediterranean Climate

Coastal Mediterranean

Location: Coastal Mediterranean peninsula, Balearic Islands, Ceuta, and Melilla. Characteristics: Hot summers, mild winters (AT 12 to 15 °C). Low and erratic rainfall, summer aridity (TPA 750 to 300 mm).

Interior Mediterranean

Location: Peninsular interior. Characteristics: Major contrasts throughout the year (AT > 16 °C). Low and erratic rainfall, summer aridity (TPA 650 to 300 mm).

Arid Mediterranean

Location: Southeast peninsula and isolated enclaves in the interior. Characteristics: Temperatures similar to the coastal zone. Very scarce and irregular rainfall, prolonged aridity (TPA < 300 mm).

Subtropical Climate

Location: Canary Islands. Characteristics: High temperatures throughout the year (AT < 8 °C). Insufficient and irregular rainfall, varies with altitude.

Mountain Climate

Location: Pyrenees, Cantabrian and Iberian mountain ranges, Central System, and Penibético System. Characteristics: Low temperatures, cool summers and cold winters. High precipitation, often as snow (TPA > 1,000 mm).