Zumaia Flysch

The flysch at Zumaia is a sequence of alternating hard and soft marine sediment layers, laid down over roughly sixty million years on a deep sea floor and later tilted almost vertical by the collision that raised the Pyrenees, then planed off by the sea into a wave-cut platform, so the layers are exposed edge-on and can be walked across like the pages of a book. The sequence includes the Cretaceous-Palaeogene boundary, the layer marking the asteroid impact that ended the dinosaurs, identified here by an iridium anomaly, and the Palaeocene-Eocene thermal maximum. Two golden spikes, international reference points for geological time, are defined at this coast. The Basque Coast Geopark runs guided walks and boat trips.

What you actually see

• The tilted layers - vertical rock strata across the wave-cut platform.
• The extinction boundary - the layer marking the end-Cretaceous impact.
• The golden spikes - internationally defined geological reference points.
• The Itzurun beach - the shore from which the sequence is walked.

When to go

April to June and September to November; low tide is essential to walk the platform, and tide tables determine the visit more than the season. Boat trips run mainly in summer and are cancelled in swell.

Honest expectations

Access to the platform depends entirely on the tide, and at high water it is under the sea. The rock is slippery and uneven. The geological significance needs a guide or reading to appreciate; without it the layers look like striped rock.

Nearby

Getaria and Zarautz lie east; Deba and the rest of the geopark coast run west.