At 1,038 km long and emptying into the Atlantic Ocean at Lisbon, which is the longest river on the Iberian peninsula ?
Iberian Peninsula subject to seasonal variations in flow. The Tagus is the longest river on the peninsula and, like the Douro, flows westwards with its lower course in Portugal. The Guadiana river bends southwards and forms the border between Spain and Portugal in the last stretch of its course. The terrain of the Iberian Peninsula is largely mountainous. The major mountain systems are: The Iberian Peninsula contains rocks of every geological period from the Ediacaran to the Recent, and almost every kind of rock is represented. World-class mineral deposits can also be found there. The core of the Iberian Peninsula consists of
Geology of the Iberian Peninsula of the Alpine belt. To the west, the peninsula is delimited by the continental boundary formed by the opening of the Atlantic Ocean. The Hercynian Foldbelt is mostly buried by Mesozoic and Cenozoic cover rocks to the east, but nevertheless outcrops through the Iberian Chain and the Catalan Coastal Ranges. The Iberian Massif consists of rocks from the Paleozoic Era. It was assembled about 310 Ma. Several zones occur in the Iberian Massif. These were the pieces that were assembled to form the block. On the north coast of Spain occurs the Cantabrian Zone. Then to the west and also