The impressive Entrance to the Canyon at Sa Calobra on Mallorca's rough western Coast
For the last two years we were spoiled with views of spectacular volcanos. We saw Mount Etna glowing red at night at and the plumes of Stromboli during the day. We got to climb the still fuming Monte Vulcano. We passed through Thera or Santorini and could see the remains of the volcano that blew up 4’000 years ago. Would we be able to enjoy such spectacular sights this year again? As the Eastern Mediterranean, the western part was also created by the collision of the African and the European Plate.
The Collision of the African with the European Plate formed Europe as we know it - the dark blue areas are the few remainders of the ancient Tethys Sea floor
Most tectonic actions in the Western Mediterranean though happen in southern Spain and the Atlas mountains of Northern Africa. The colliding plates are less twisted than in the east and there are no subduction zones. The reason is easy to understand. The Spanish peninsula is part of the European continental plate and touched Africa first. The Tethys Sea with its limestone and clay floor was further east.
The Closing of the Tethys Sea in the Eastern Part of the Mediterranean
Spain acted as a sort of pivot – where Africa met resistance it swung to the east thereby closing the Tethys Sea. Subduction zone opened in the Eastern Mediterranean. The heavier sea floor disappeared under the lighter European plate. The water that the sinking crust pulled with it got super-heated and created the vents through which magma rose. Hence the string of volcanos ranging from the Tyrrhenian to the Ionian Sea. Today, only tiny pockets of the Tethys sea floor are left.
The Volcanos on the Iberian Peninsula are primarily around the Betics System in the South
Nonetheless, African’s pressure on the Iberian plate its marks. The Pyrenees between France and Spain were lifted, the Balearic Sea ridge was folded and the trough of Valencia, similar to the trough between Basel and Mainz, was created. Completely flooded it is invisible but shows up on sonar charts. There are a few volcanos at the eastern end of the Pyrenees but they are too far inland for a visit. They are dormant now and heavily forested. You need a geologist’s eye to detect them.
Most Volcanos in La Garrotxa in the Pyrenees (at the back) are already weathered down
Further south, in the mountains of Granada, there was more tectonic action. The narrow stretch of the Tethys Sea between Spain and Africa was folded and lifted. It now forms the Betics mountains in Spain and the Atlas in Northern Africa. The pressure on this stretch of sea floor must have been tremendous. It cracked in several places and magma was able to rise, forming a chain of volcanos. As in Greece and Anatolia, the magma flows were accompanied by vapors containing precious metals. There were a lot of silver mines in southern Spain. Heavily mined by Phoenicians and then Romans, these mines are now depleted but the shafts can still be found.
Mining the Silver-Sulfid Galena in Spain was certainly
unhealthy and all done by Punic & Roman Slaves
About 6 million years ago, these young mountains – in their ever-changing configuration -closed the Mediterranean to the Atlantic. For more than half a million years, the Mediterranean became land locked. The rocks of Gibraltar and Jebel Mousa – together called the Pillars of Hercules - are the surviving witnesses to this event called the Messinian Salinity Crisis.
600'000 Years ago, Animals could walk from Africa straight to the Baleares and they did as we know from fossil records.
The combined water contribution from Ebro, Rhone, Po, Danube, Dniester, Dnieper and Nile could not compensate the Mediterranean’s evaporation losses. The sea started to dry out. Water levels dropped to 3’000 meters below sea level. It must have been devilishly hot down there and completely lifeless. Think about Dead Sea to the power of ten. Seawater became so concentrated that salt and gypsum crystalized and formed mighty deposits at the sea bottom.
5.3 Million Years ago, the Straits opened up again. It took 2 years to refill the Mediterranean
Some of these mighty salt deposits were later lifted above sea levels. In the Provence and in Sicily large salt caves can be visited today.
Many of these giant Salt Cavern can be rented for Special Occasions
Compared to the Eastern Mediterranean, the West is thus relatively calm. There are far fewer earthquakes than in Italy, Greece and Turkey.
Map showing the Frequency of Earthquakes in the Mediterranean
We won’t see any volcanos this year. But there will be plenty of limestone cliffs in Liguria, the Côte d’Azur and the gentle Balearic ridge which will compensate us with their caves and beautiful inlets and unspoilt natue
The Mountains surrounding the Canyon from the first Picture are just 1'000 meters high