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Welcome and thank you for taking an interest in Costa Quebrada. The geological wealth of this tough, rough, irregular coastline can be matched by only few others in the world.

To know more about the unique Geodiversity tour and its lessons is to know more about our world and how it was formed. The satisfaction you will gain takes a little effort, but it is well worth your time. Just a walk of a few kilometres is in itself a visual wonder, but to see the variety of coastline formations, rocks, soils and fossils uncovers and exceptional past.

These audio-guides accompany the interpretation boards located at eight points along this stretch of coastline (La Virgen del Mar, San Juan de la Canal, Covachos, La Arnía, Los Urros, Portio, Somocueva, and el Madero). Through the use of the audio guides together with observing the interpretation boards you will understand the processes that have shaped its past and present climates, landscapes and revel in the biodiversity of life along one of nature?s premier exhibitions of history written in the rocks.

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Over 120 million years ago this section of coastline was a point on the seabed. The internal forces of the earth separated the African and South American continents to form the Atlantic Ocean, whilst the north coast of the Iberian Peninsula separated from western France, creating the young Bay of Biscay in the area between the old rocks of Brittany and Galicia.

At this time, the majority of Cantabria was underwater. River sand and mud settled on the seabed and rich tropical reefs appeared, crammed with organisms very different from those we see today. Over time, these organisms were buried by new layers of loose material. The climate changed slowly, bringing new forms of life from the north and south, protected by the warm or cold waters. Over hundreds, thousands and millions of years, the organisms were completely buried by sediments and eventually transformed into flat layers of rock.

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A monumental event transformed the flat layers of solid rock built up by organic material and sediment deposited over millions of years. The African continent began to move northwards, pressuring and uplifting young rock layers between Africa and Europe to form the present day mountain chains of southern Europe: The Cantabrian Mountains, the Pyrenees, the Alps, the Balkan Mountains and the Carpathians.

This movement also affected the rocks along the Costa Quebrada. Folding of the horizontal layers of rock formed a large crease running west to east, emerging from the sea floor and exposed to the erosive effects of the wind and waves.

This folding and the subsequent crease left a rich trail of formations and sand deposits along the Costa Quebrada.

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In addition to the mountain chains in the south of Europe, the pressure of Africa on the European continent caused additional folding in the form of huge creases in the land. Raised areas are known as anticlines, whilst sunken, valley-like areas, are known as synclines. The Costa Quebrada lies on a huge syncline running from west to east. This rock forms almost the entire peninsula on which the city of Santander is located.

The Virgen del Mar is located practically in the centre of this syncline, at the point where the layers of rock, or strata, are almost horizontal. As we move to the east or west, however, the rocks gradually arch to form two distinct types of coastline. The eastern coastline is gentle, with the strata gradually descending towards the sea, whilst to the west the coast becomes progressively more abrupt as the strata inclines to an almost vertical position.

The rocks at the centre of the syncline are the youngest rocks along the Costa Quebrada and in Cantabria in general. Formerly under water, these rocks contain fossils of organisms similar to those found in our seas today.

Wave action has enlarged a rock fracture between the Virgen del Mar and the low cliffs at our feet. The sea deposits sand in this sheltered canal, creating a beach at low tide.

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The sea?s surface separates two worlds, but is not a rigid boundary. Several ecosystems inhabited by organisms adapted to surviving in an intermediate and constantly changing environment that exists between the marine and terrestrial worlds.

Vegetation in this area is characteristic of cliff areas along the Bay of Biscay. Plants occupy areas where the soil depth and salt residue from the wind and waves provide a suitable habitat for their survival. These plants are hardy, but at a a varying parts of the season, differently beautiful.

Alongside other plants, sea thrift flowers on the limestone rocks during the springtime. The tufts of small, pink, aromatic flowers provide rich, sweet nectar for insects, which depend on these flowers for pollination, whilst organisms such as lizards and birds feed off the insects.

It is common to see the small redstart bird flitting between the limestone rocks, wagging its orange tail merrily, as it looks for food along the cliffs where it makes its nest.

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The cove at San Juan de la Canal lies at the point where the youngest and oldest rocks on the Costa Quebrada meet.

As a result, the beach acts as a division between the oldest materials deposited at the end of the age of the dinosaurs, located to the left, and the younger materials deposited after their extinction (to the right).

The youngest rocks form the cove, the rocks in the middle of the beach, and continue along the cliffs to our right as far as the Virgen del Mar island. The rocks get progressively older, however, as we move to our left, or westwards, towards the beach of Covachos.

The cove is formed of dolomite rocks, which are easily dissolved by rainwater. Traces of this rock are visible in a line running from the rocky outcrop above the paved path, which to the right of the information panel.

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The headland on the right separates the beach from the canal inlet. This small, beautiful, rocky tidal inlet receives water from the eastern hillside of the Picota mountain and the Otero River; after it passes through the villages of Maoño and Azoños. This river has been channelled, and consequently, denaturalised for a large part of its course. Man has disused the river and great care is needed to repair the genius of nature.

At the point where the Otero River reaches the inlet lays the remains of an old mill that once used the force of the water to grind corn. This testimony to human activity on the Costa Quebrada now lies forgotten on the bottom of the La Canal inlet.

The inlet was once a privileged site for elver fishing, but in recent years the number of elver has fallen dramatically.

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To the left you can see the small, low cliffs surrounding the beach. These cliffs were formed at a time when the beach had no sand and, therefore, the rocks were easily eroded by the waves.

Sand dragged in by the summer tides subsequently accumulated in the small cove. As the sand dried out on the shore, the dominant north-east summer winds piled up the sand at the left end of the beach, forming a small sand-dune. Small plants, resistant to arid, sandy environments, such as couch grass and spurge, have stabilized the tiny mineral fragments with their roots, creating sand dunes. Sand-dunes are one of the rarest; most threatened and most abused coastal ecosystems. Even being used as reserves, carried away by large, heavy trucks for the more popular tourist beaches.

The San Juan dune once stretched along the entire end of the beach. However, the former car park and the constant trampling of access routes to this popular beach by visitors, has significantly eroded the dune?s extension. The car park has now been turned into a paved footpath. Conservation efforts that delineate the extent of the sand dune have recently been implemented by the work of volunteers.

In 2007, a sundial was installed on the green area above the beach to explain the biological and climatological processes taking place along Costa Quebrada with reference to the changing seasons, temperature and climate. This artistic measured system was designed by members of the association of Costa Quebrada funded by the local municipality.

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The rocks and golden sand deposited by the sea at Covachas Beach are in a constant state of change due to the storms, waves and tides creating some of the most impressive and attractive geological formations along the Costa Quebrada.

Looking at the sea, the Island represents the last remains of the old coastline. On the left, we can see the remains of the layers of inclined rock that joined the island to the mainland. The small grassy area crowning the island once formed part of a river valley, where the river met the sea between the island and the cliffs on the right. However, coastal erosion gradually destroyed part of the rocks, creating a cove and separating the island from the shore. The river, which now is a stream, flows into the sea from the cliff-top and a walk among the formations is worth the effort.

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The semicircular cove and island at Covachos were formed by erosive processes, as mentioned earlier, and the beach below the high cliffs was created by the deposition of sand in the more sheltered areas.

To reach the coast, the waves have to negotiate the island. The waves consequently collide in the more protected area behind the island, dropping sand in a line on the seabed. This process has formed a tombolo, a sand bar which connects the island with the mainland during low tide.

A flat shelf formed by the straight edges of the rock layers is visible at low tide. This shelf runs from west to east and was formed by the same tidal action that created the cove. Snorkeling in this area is an nteresting, fun activity to be enjoyed.

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During the summer months, red seaweed grows in abundance on the shelf?s flat rocks. In autumn, the seaweed is dragged off the rocks by the strong wave action and deposited in large piles on sheltered coves like this one.

This red seaweed is collected and its extractions used to produce gelatin for pharmaceutical, cosmetic and scientific use. For many years, this seaweed provided additional income for the Costa Quebrada?s inhabitants, and the rusty remains of the ?lift? structure used to raise the seaweed from the beach to the road using a simple pulley system, are still visible.

These underwater fields of seaweed provide food and protection for a wide variety of animals that are also dragged backwards and forwards with the rising and falling of the tide.

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Arnía?s beach and rock shelf are spectacular examples of coastal formations well known in Cantabria.

In front of us, an almost vertical rock face rises up out of the sea. This brownish layer of limestone acts as a protective wall reducing the erosion of the soft grey layers of rock behind.

Wave action has sculptured the resistant layer of brownish limestone in several places, leaving a line of abrupt pointed rocks. Two of these rocks form impressive stacks and cut off the beach to the north, hence providing protection for the soft rocks behind.

Due to varying deposition conditions, the brownish limestone is very different from the sheets of younger, grey, clay. When the limestone was deposited, the sea water was warm and clear. However, a major climate change stirred up the clear water, turning it cloudy. From this moment onwards, the deposition of clay formed more delicate grey rocks.

The sea flows through passages in the wall of rock cut by the waves, attacking the previously protected soft rocks behind. The rocks have eroded rapidly, in geological terms, leaving a flat, rocky shelf, only visible at low tide. The shelf is surrounded by a semicircular cliff that is also undergoing a rapid process of change.

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At low tide, a unique ecosystem is exposed on Arnia´s shelf. This marine ecosystem is subjected to the rise and fall of the tide, making survival conditions very difficult. Organisms have to deal with dry periods, variations in water temperature in the rock pools, wave action and isolation at low tide.

The shelf is scored with crests and channels, running parallel to the coastline. During low tide, the organisms distribute themselves between the crests and the channels:

The crests and channels closest to the shore are the driest areas. Here we find more resistant organisms, such as green seaweed and crabs.

On the central crests, organisms are less exposed to the elements. Here we find species such as limpets and acorn barnacles, which take shelter in their resistant, water-proof shells during low tide. Meanwhile, organisms intolerant of dry conditions, such as coloured and beadlet anemones, sea urchins, pink seaweed and other organisms settle in rock pools.

Deep-water seaweed and animals seek protection in the channels closest to the low tide mark.

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From this point in Costa Quebrada we are able to enjoy stunning views of stacks, headlands and small islands.

With a closer inspection, we can identify three different types of rock, in the form of giant flat layers which were forced into a nearly vertical position by the internal forces of the earth.

In the distance, the line of small islands running out into the sea forms a layer of hard, resistant limestone. Closer to the coast, a layer of younger brown limestone also withstands continuous wave action, protecting the soft, grey, clayey rock, known as marl.

These layers were originally deposited in large, horizontal sheets on the seabed. As the climate changed, new materials were deposited in the layer above. Consequently, the layers reflect the climatic conditions at the time the materials were deposited.

Climate changes altered the rock type and also the organisms living in the sea. By studying the remains of tiny, ancient animals we can identify and understand these climate changes. Fossils reflect the dramatic modifications in the surrounding environment. An example of a fossilized marine organism found in this area is the Orbitolina.

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The chain of small, white islands in the distance are the remains of a resistant layer of limestone that was separated from the mainland. These islands are an ideal nesting site for sea birds. The soft layer of rock that lay between the islands and the present day mainland has been completely submerged.

The needles of rock, in front of us, protruding from the sea, represent another resistant formation in this area. This layer forms a serrated line which extends eastwardly, parallel to the cliffs, as far as Arnía.

These needles are sections of hard rock that have resisted erosion by wave action that now wears down the grey rock seen below us. Over time, loose, fallen fragments of hard rock have created a small shelf on the seabed.

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Characteristic tough plants, acclimatized to extreme growing conditions, for example, salt, the lack of soil and strong winds, nevertheless prosper on the golden cliffs.

Above us on the cliff-top, the soil is richer and heather grows in abundance, turning a beautiful pink during the autumn. Of the four species of heather found within the Costa Quebrada, the most prominent is the creeping heather, Erica vagans.

In addition to the creeping heather, with its tiny, pink flowers grouped at the tips of each stalk, other species with larger flowers also grow on the cliff-top. Of these, the Cantabrian heather, Daboecia cantabrica, is the most outstanding, and is particular to this region.

Alongside the heather are thorny plants, such as gorse, which contributes the beautiful yellow flowers during the springtime.

Coastal heath land is threatened throughout Europe. Despite being designated as protected areas, under the Habitat Directive, they continue to suffer from vehicle damage.

Heavy vehicle traffic, specifically during the summer holiday season, also threatens green areas, such as the surrounding meadow with its carpet of fine fescue grass, known as love grass, due to its soft, mattress?like texture.

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From here, at the end of Portio beach, we can identify the three coastlines forming the basic profile of the Costa Quebrada.

The furthest and oldest formation is called The Urros, made famous by the Cantabrian author, Jose Maria de Pereda in his 19th century book, Sotileza. This fictional work describes fishing boats returning to port to escape the strong northwest wind, specifically the infamous gale of 1878.

The islands and peninsula protecting Somocueva Cove are the only remains of the tropical reef that once existed on top of the limestone.

The following resistant layer of limestone forms the two sides of the cove?s entrance and the vertical stacks we walk over in the areas that have not suffered from erosion.

Thin, vertical sheets of grey clay, known as marls, have formed behind the hard limestone. The hardness of the marlstone depends upon its lime content. Layers of marlstone containing more lime are harder and, therefore, more resistant to the pounding of the waves.

If we walk along the beach from the information board to these hard, limestone rocks we are effectively making a journey through time, travelling back some ten million years. Many of the climatic events that took place during this period are recorded in the rocks around us.

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The housing development in front of us is a product crude urban development, real estate speculation, and the illegal abuse of natural heritage. This is one of the most significant and notorious examples of this type of coastal destruction in Costa Quebrada, as well as Cantabria. It serves as a reminder of the effects man can have on millions of years of geodiversity.

Urban development of Costa Quebrada began in earnest only 15 years ago, and is therefore, a surprisingly modern phenomenon. However, the violation of coastal laws and the continuous search for new, untouched natural areas for building shows no sign of stopping. The houses we see before us are the sad consequence of the transformation of natural areas into bricks and quick, insensitive money.

This provides a vivid example of the paradox behind the search for a better ?quality of life? by the sea. And ironically, instead of contemplating the wonders of geology and the sea, we find the view of Portio dominated by cement and tasteless architecture.

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120 million years ago the Costa Quebrada was underwater. The dinosaurs dominated the earth, leaving their footprints along the coastline, which at that time awas the North of Castilla, the Rioja and Aragon.

During this period, the clear, tropical sea shaping the rocks of the present day Costa Quebrada contained a large coral reef. This reef was inhabited by big molluscs similar to present day clams, but with large, twisted, horn-shaped, asymmetric shells.

The accumulation of the remains of the molluscs together with fine lime-rich silt formed a thick layer of material that was later buried by other materials and compacted to form the hard, limestone rock we see today.

As the internal forces of the earth folded the layers of rock, wind and wave erosion uncovered resistant material along the oldest section of this part of the coast. The peninsula at Somocueva is the only surviving remains of this form by an ancient tropical reef.

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A change in the climate interrupted the formation of the peninsula in Somocueva and Urros. Rainfall increased inland and the rivers carried huge quantities of sand and silt to the sea, burying the tropical reef and wiping out the organisms living on it. These organisms needed clean water to survive and, as a consequence of the climate change, the water had turned cloudy and no longer provided suitable conditions for their survival.

During the following 15 million years, a long beach deposited sand in the area, and was occasionally replaced by an estuary similar to the present day Pas Estuary. Fine, dark silt deposits accumulated during this period and the beach was eventually fossilized by wind and water erosion.

The sequence of sandy rocks and silt formed the most vulnerable layers of rock in the Costa Quebrada, and has been almost entirely been changed by wave action. However, the peninsula at Somocueva protected the last remains of this large, fossilized beach on the narrow stretch of land joining it with the mainland.

Descending to the beach we find layers of sand broken up by a blue-grey, silty rock stained with sulphur. These are the last surviving remains of the sandy period along the Costa Quebrada.

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The River Pas deposits sand on Somacueva beach as it flows into the Bay of Biscay and the sand builds up on the beach during the spring and summer tides and is occasionally dragged out to sea by winter storms. Exposed to the elements, the sand is transported by the wind and accumulates in the more protected areas at the end of the beach, where it is fixed by the roots of plants like couch grass and spurge. This process has created a small, vulnerable active dune system on the narrow stretch of land linking the peninsula with the mainland.

Unfortunately, the dune, which is sensitive to trampling, provides the principal access route to Paloma beach at the eastern end of the isthmus linking the peninsula to the mainland. Consequently, the beach is threatened with erosion from the continuous coming and going of people to and from the beach; a large part of the ecosystem has already been damaged.

A series of protective measures have been introduced, such as the installation of fencing and the planting of vegetation to act as a windbreak and retain the sand. However, whilst people continue to use the dunes to access the beach, these methods will not prevent future and the consequential extinction of the dune.

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Here we can see the polished edges of the flat layers of rock that built up slowly on the seabed following the deposition of clay and the remains of marine organisms. These tilted layers of rock were folded by the internal forces of the earth.

This landscape is continuously changing.

A layer of hard, brown limestone forms an inclined wall, closing off the cove on one side. Constant wave attack has eroded the soft, grey rocks that had been deposited on the limestone, although some thin layers of clay like rock, known as marl, are still visible at the end of the small beach in the distance. These layers of soft rock will survive until they too fall victim to erosion by the pounding of the waves.

With the biggest waves, water passes through two cracks in the weakest part of the rock wall. Consequently, the soft, grey rocks behind the wall have eroded away, flaking like pastry to leave a naked, grey cliff-face that is gradually retreating over time.

Further along, a third weak point on the wall is starting to show signs of the effects of persistent erosion by the sea. The soft grey marl is gradually eroding away through a small orifice at the bottom of the wall, forming a funnel.

Within a few thousand years, the hole in the marl will stretch as far as the eroded flat area and, consequently, enlarge the beach. This is how the spectacular coastal formations of Costa Quebrada have formed.

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At your feet, a deep crack runs into the earth, marking a weak point through which the sea can enter. This large fracture cuts through the layers of rock, pushing them to each side.

The hard, brown rock we are standing on forms the cliff running west towards the beaches of Liencres. This hard layer is the same rock that forms the rock-wall on the north side of Madero cove. Now separated by hundreds of metres, this was once a continuous layer of rock.

During the huge movement of the earth, this rock split open, forming a fault, whilst the layers of grey, clay rocks were deformed and folded.

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