HOW WAS THE FLYSCH FORMED?
A story from below the sea
Each layer of the flysch was formed by sediments and small shells from marine organisms settling under the sea that separated the Iberian Peninsula from Europe.
Walking across its layers today allows us to examine thousands of metres of marine sediments that accumulated between 105 and 50 million years ago.
The current landscape
The current landscape was formed very recently. Over the last few thousand years, sea erosion has shaped the cliffs we see today, revealing this great book that chronicles the history of Earth.
The great collision
Gradually, over more than 20 million years, Iberia continued to collide with Europe to form the Pyrenees. The 5,000 m of marine sediments were deformed and uplifted to their current vertical position.
A deep, calm sea
The seabed stabilised, resulting in the calcareous flysch that we can see today between Deba and Zumaia. When Iberia started colliding with Europe in the east, the sandy flysch of Zumaia and Getaria was formed.
Opening up of the Bay of Biscay
Iberia moved away from the coast of Aquitaine, opening up the Bay of Biscay and creating a deep basin. This is where the black flysch that we can see today in Deba and Mutriku was formed.