Geomorphology in a World Cultural Heritage Site: The City of Porto

Located in the northwest of Portugal, along the Douro River estuary and facing the Atlantic on the west side, Porto is the second largest city of the Portuguese territory. Retaining in its urban structure, several characteristics that reflect the economic, social and cultural evolution over several epochs, the historical center of Porto is a World Heritage Site since 1996. Holding a complex structural framework, given its location in a contact strip between the Central Iberian and the Ossa-Morena zones of the Variscan Iberian Massif, the city is carved in granites associated with a narrow belt of metasedimentary rocks and different types of gneisses and amphibolites. Some continental, fluvial and marine deposits overlap these outcrops, reflecting a (neo)tectonic and paleoclimatic evolution that marks the geomorphological context of Porto. The steep slopes of the Douro valley, leading to slope movements, major river floods or the erosion problems linked to ocean dynamics, are stored in the memory of the inhabitants of Porto and are reflected in several features of contemporary land management practices.