Cenozoic
Compression conditions were experienced spreading to the west along the northern margin of Iberia. This caused narrowing of the Bay of Biscay, with subduction of the bay floor happening forming the Cantabrian Mountains, starting at the very end of Cretaceous and into early Eocene. The subduction ceased at 54 Ma.
Stress from the northeast edge of Spain's collision with Eurasia affected the interior, raising the Iberian Basin to form the Iberian Chain mountain range, north east of the centre. The Azores-Gibraltar transform zone activated at about 30 Ma. This zone appears as a ridge on the Atlantic Ocean floor, and is apparent even today as an earthquake zone. Africa moved eastwards with respect to Iberia and Eurasia. This opened up the Valencia Trough and the Balearic Basin. Extension in this south east side of Iberia spread from southern France. The spreading reached and formed the Alborian Basin between 23 and 20 Ma.
Africa converged towards Eurasia, and the direction changed from north north west to north west in the Tortonian. This change in compression formed the Baetic Cordillera on the Mediterranean coast in the Middle Miocene. Basins were inverted and raised up in the Iberian Central System, and also the Alboran Basin. The crust still continues to fold in these areas since the Pliocene. Some coastal areas have been uplifted hundreds of meters in the Pliocene. Also new shear zones appeared in the Alboran Basin.
The Ninyerola Gypsum unit is fifteen kilometres south of Valencia. It consists of layers of gypsum and marl and limestone. Nodules of gypsum from this formation have been used as alabaster for carving sculptures. This was deposited from a fresh water lake, high in sulphates but low in chlorides.
The Duero Basin is the largest Tertiary basin in Iberia. It is in northwest Spain. Oligocene and Miocene continental deposits are up to 2.5 km thick. It is bounded by the central system to the south, the Iberian range to the east, and the Cantabrian Mountains to the northeast. The Cantabrian Mountains are the main source of the sediments in this basin. The Duero River started to drain the basin 9.6 Ma by connecting it the Atlantic Ocean. Gold was mined in Roman times in the basin. Las Medulas is the most famous mine. Greasy wool was used to trap gold flakes washing past from the alluvial deposits. North of Ribón is another 2000 year old gold mine.
Two Eocene basins in Portugal are the Mondego and Lower Tagus basins which are elongated in the southwest direction. Simultaneous with the formation of these grabens the Algarve basin was uplifted. In the Miocene the Lusitanean Basin was compressed, and the Portuguese Central Range and Western Mountains was formed. These too trend south west. The mountains also form piedmont or fore-deep basins. Faults developed aligned south south west. These faults developed some pull apart basins.
In the Late Pliocene (2.6 Ma) there was increased uplifting and previously deposited sediments were incised by erosion. The coast of Portugal has been rising at about 0.1 mm per year since then.
Read more about this topic: Geology Of The Iberian Peninsula