GETXO
THE GOLDEN SPIKE
THE GORRONDATXE EOCENE
The importance of this place of geological interest lies in the Lutetian stratotype found here.
What does that mean?
A stratotype, or GSSP, is an internationally agreed upon indicator that marks the best boundary between periods of the geologic time scale around the world as shown in the fossil fauna of the area.
This stratotype can be recognised by a golden wedge you can see on the face of the cliff, which has made Gorrondatxe a worldwide reference for studying the base of the Lutetian stage, which is around 47.8 million years old.
You can see the Lutetian layer here, which is made up of marl and turbidite limestone that spans more than 7 million years. The materials in the outcrop today were deposited in a sea basin that was around 1500 metres deep.
DID YOU KNOW... There are only 75 stratotypes in the world and seven of them are on the Iberian Peninsula. And three of them are in Euskadi. Two are on the beach from Itzurun to Zumaia and one is on the Gorrondatxe (Azkorri) beach in Getxo.