Relief Units, Rock Types, and Urban Hubs of the Iberian Peninsula

Relief Units of the Iberian Peninsula

External Relief Units

• Axial Pyrenees (3)
• Prepyrenees (4)
• Cordillera Costero Catalana (15)
• Ebro Depression (6)
• Guadalquivir Depression (12)
• Subbética Cordillera (13)
• Penibética Cordillera (14)

Internal and Peripheral Relief Units

Peripheral Units

• Macizo Gallego (1)
• Cantabrian Mountains (2)
• Iberian System (8)
• Sierra Morena (11)

Internal Units

• Cuenca del Duero (5)
• Central System (7)
• Cuenca del Tajo (10)
• Montes de Toledo (9)

Rock Types of the Iberian Peninsula

The Iberian Peninsula is composed of three main rock types:

• Siliceous Rock: Found in the Macizo Gallego (1), western Cantabrian Mountains (2), Central System (7), Montes de Toledo (9), Sierra Morena (11), Axial Pyrenees (3), Cordillera Penibética (14), and part of the Cordillera Costero Catalana (15).
• Limestone Rock: Found in the eastern Cantabrian Mountains (2), Prepyrenees (4), Iberian System (8), Cordillera Subbética (13), and part of the Cordillera Costero Catalana (15).
• Clay Rock: Found in the Cuenca del Duero (5), Cuenca del Tajo (10), Ebro Depression (6), Guadalquivir Depression (12), and part of the Cordillera Costero Catalana (15).

Area 16 is dominated by volcanic rocks like basalt.

Major Cities of the Iberian Peninsula

Cities with more than 500,000 inhabitants include:

• National Cities (over 3 million): Madrid, Barcelona
• Regional Cities: Bilbao, Zaragoza, Valencia, Seville, Malaga

Urban Hub 3: The Mediterranean Axis

Urban hub 3, also known as the Mediterranean Axis, encompasses several coastal cities along the Mediterranean Sea. This axis is dominated by Barcelona in Catalonia, Valencia in the Valencian Community (with significant importance also placed on Alicante), and Murcia in the Region of Murcia. It also affects a small part of Aragon.

Bifurcation of the Andalusian Urban Axis

The Andalusian urban system is bicentric, with its population spread across numerous cities, but its economic functions concentrated in two main cities: Seville and Malaga. Seville's influence extends northwest, primarily towards the Atlantic coast, while Malaga's influence extends southeast, primarily along the Mediterranean coast.