Flysch - Tides - Beautiful Coast - Zumaia, Deba, Mutriku - Basque Country

 What we see changes what we know.

What we know changes what we see.

Jean Piaget

Viewed from the Chapel of  Saint Telmo (patron saint of sailors)
Home on the cliff above the Itzurun Beach

If a sandy warm beach is what you are looking for, this isn’t the place. Described at times as ploughed or windswept, this location made me feel like I had stepped into a completely different world, so much so, that I couldn’t come up with words to adequately describe it. 

 As an alternative, I am sharing parts of a wonderful description by www.thinkspain.com:  ‘If raw nature, Jurassic landscape and unique, one-off panoramas are your thing, this officially-protected Basque Country biosphere is very much worth the detour.’  ‘… cliffs that look as though they were turned out of a jelly-mold and then hit by a gale heading north before they were properly set.’ or ‘Rippled surface covered in heathland grass on the top, and barcode furrows on the ground, the rockface in the middle looks as though it had been sliced with a bread-knife.’  Feel free to compare that depiction with the pictures in this post.

Flysch is an archaic word that was coined in 1827 by a Swiss geologist who used the term for layers of alternating thin deposits of sandstone and shale in the Alps. The name comes from the German word fliessen, which means to flow. Geologists later realized that these were deep marine sediments.  This old term continues to be applied to thin layers of alternating sandstone and mudstone, plus or minus limestone, and that is unlikely to change even if it has an outdated and erroneous meaning. 

The tidal range is large along this coast, ranging from 6.5 feet (2m) to 13 feet (4m). Fortunately, tidal data is available, so make sure you choose times or days when a large tidal range produced particularly low tides during daylight hours. This is when rock viewing is at its best!  I had to hike this Flysch Route on two different days because of the tides.

Representing over 60 million years of earth’s history, these flysch cliffs are also a longtime favorite of geologists.  These formations are the result of coarse-grained sediment dragged by underwater avalanches and dumped in deep ocean troughs beneath the continental shelves, which, when pulled ashore, give the landscape its groovy texture. Flysch are rocky fascias made from sediment, the 'dregs' of the sea, alternating layers of hard material (limestone, sandstone, slate), with soft material  (clay, loam, marl). The end product is a ‘stripey’ surface in different shades of grey and beige, from almost charcoal and brown to nearly white, and the appearance of its having been raked over.  

Goikola was just below Lastur in this map
Over two days, I hiked from Zumaia through Deba and ended in Mutriku 
To see the coastal flysch formations

Low tide in Deba
Tidal range can be up to 13 feet (4m)

You have to time seeing the flysch rock formations at low tide
My first view of this wonderful flysch as the fog lifted in early morning

Waves, flysch formation, a bit of sand

Going straight up a cliff

Somewhat like the pages of a book
Assorted 'stripey' layers of various colors and thicknesses

Close-up of these layers

Walking by an old watering station from 1880
Near Elgoibar

By accident, I followed the Camino de Santiago for about 2.5 miles (4km)
While attempting to walk the coastal Flysch Route for 12.5 miles (20km)

Moving at a rate of only one mm per year, Iberia collided with Europe giving place to the Pyrenees.  Flysch layers emerged and turned vertical.  Over thousands of years the sea and the rain have eroded these sea cliffs.  They are like pages of a huge twelve mile long (20km) book charting the global environmental trends and geological events over the course of more than 60 million years of our planet’s history, focusing on a sequence of sedimentary rocks that were deposited between 110 and 50 million years ago.

Walking along the coast by Zumaia, Dema, and Mutricu – is akin to passing through 500,000 years of history with each step.    Here you can enjoy a great walk through a beautiful landscape that has taken millions of years to take shape.  You can travel through time to the geological roots of this area, roots that are the pillar of the landscape, and of life itself.

Apart from the impressive rock formations, Zumaia harbors important fossil evidences. The Cretaceous-Paleogene boundary, a rock layer that marks the end of the Mesozoic era and the extinction of non-avian dinosaurs, is found in Itzurun beach. Fossils of ammonites, ancient mollusks resemblant of the nautilus, are also found in the rock layers.

The Zumaia sequence is famous for its diversity of trace fossils. Most people are used to seeing fossils that are body parts like shells or bones. Trace fossils, in contrast, are the impressions that organisms leave in the sediments as they forage for food. An entire field of geology (ichnology) involves the study of ichnofossils to figure out what type of organisms made the trace or track. 

Zumaia had an old mill using tidal energy to grind grain.  For centuries, these tidal movements were used to generate power using a tide mill. The earliest written reference to the mill dates from 1203, and we know that it continued working up until 1885.  An example of how people figured out how to generate renewable energy 800 years ago!  The tide mill had two millstones, one for wheat and one for maize. The mill building was known as Presako Torrea.

A version, a bit greener, of the flysch

So many variations on that theme

The farthest point that you see is about 11.2 miles (18km) away
I only have a little left to walk

Aerial view to give you a better idea
Not my picture - one from a tourism site

Another portion of the flysch, more vertical

Why you have to see it at low tide
Some of it gets completely covered at high tide

Tide coming in - time to get above it

From: www.landscapes-revealed.net 

This image shows the Zumaia sequence from west (oldest layers) to east (youngest layers). The ages of the 10 m.y. part from 65.5 Ma to 55.8 Ma (K/T to P/E) are certain. But the layers extending east and west of this part include at least another 10 m.y. 

The top line are the names of the Periods: Cretaceous, the end of the Mesozoic Era, and Paleogene (formerly the Tertiary), the beginning of the Cenozoic Era. The Paleogene is divided into two Epochs: Paleocene and Eocene. The Paleocene is divided into three Stages (D/S/T).

From oldest to youngest, the labelled events are: (1) K/T—Cretaceous/Tertiary boundary, although it should be labelled K/Pg since the Tertiary is now the Paleogene. (2) D/S—the boundary between the Danian and Selandian stages of the Paleocene. (3) S/T—The boundary between the Selandian and Thenatian stages of the Paleocene. (4) P/E—the boundary between the Paleocene and Eocene Epochs. Boundaries are based mainly on fossil content and typically mark times when there was a significant change in organism populations.

For preservation purposes and to enhance awareness, this long flysch rock formation became a part of the UNESCO Global Geoparks program in 2015.  When I walked it, I didn’t see more than a dozen people in two days.  There were a few times when I wished there would’ve been a few more signs or people since I got turned around for a couple of miles before finding my way again.  Being able to ask someone for directions would’ve been a bonus.  Regardless, it was well worth visiting.

To find out more about the biopark: 

Geology - Geoparkea - Flysch & Karst experience

Basque Coast Geopark - Geoparkea - Flysch & Karst experience