What if mountains were to emerge from the Mediterranean Sea?
The Mediterranean Sea represents, for most of us, a holiday destination where we lay on the beach, or have drinks listening to the sound of the cicadas. We see it as a vast blue water surface, as a flat horizon under a nice sunset. What's happening beneath this surface? Do we really know this sea as well as we think we do?
Now what if someone told you that mountains are beginning to rise from the bottom of this sea, unseen from all?
By the way, what does the bottom of the Mediterranean Sea look like?
The bottom of the Mediterranean Sea is far from being flat. It is divided in two zones: the Western Mediterranean and the Eastern Mediterranean. The limit between these two areas is a shallower part, more or less between Sicily and Tunisia (click on the map). The Mediterranean is very deep, going as deep as 5125 meters in the Eastern part (in the Matapan trench, south of the Peloponnese). This trench is deeper than the Mont Blanc is high (4808 meters)! The Western Mediterranean is also quite deep: the depths reach often 2500 meters quite near to the shores, for example off the Algerian coasts or off the coasts of Corsica.
Now then, what's the relation between these marine depths and our mountain range ?
All these sharp topographical changes are due to the movement of tectonical plates. These plates are pieces of the terrestrial crust that move very slowly one against the other. There are two different kinds of tectonical plates: the continental plates and the oceanic ones (click on the drawing). The second ones are made of a much heavier material and are much thinner than the continental plates. The continental plates can also be, partly, under water (under seas or oceans), and that is the case in the Mediterranean Sea.
In the Eastern Mediterranean, the African continental plate is sliding under another continental plate, at a speed of 8 to 35 mm per year (depending on the place where the measurement has been made).
Just realise: the Mediterranean is the only basin in the world where two big continental rigid blocs (Africa and Europe) are actually beginning to collide!
You can figure yourself the collision between two continental plates as the collision between two big pieces of « millefeuille » (a cake made of alternate layers of cream and pastry). If you push them one against the other in a horizontal movement, they are going to collide, form folds and finally create a big heap between your hands. This is just how the Alps and the Himalaya were born. And this is just what is beginning to happen now, at the bottom of the Eastern Mediterranean. Of course, for the moment, there is only a big hump, 1500 kilometres long (as long as the Alps) and 100 to 200 kilometres wide. This curved structure goes from the Western coast of the Pelopponese to the south of Turkey, via the south of Crete.
If the process doesn't stop, a mountain range will take several million years to form. It is then clear that we will never sea these mountain summits emerging from the water. But isn't it just exciting to think that, beneath the surface of this sea where most of us have been swimming, a future mountain range is being born?
