Uncommon places

Costa Vicentina © João Mariano

Costa Vicentina
Land, sea and immensity

From Odeceixe to Cape St Vicent is one of the most beautiful stretches of the Portuguese coast. The St Vicent coast rises in proud hills, carved out of the mighty promontories and enclosed bays, bordered by beaches of sand and rock. Rocky tones face the watery depths of blue and the emerald green of the ocean floor.
In this meeting between land and sea, where the elements are locked in eternal struggle, we bear witness to the immensity of time and space. The sea stretching far out of view, restricted only by the line of the horizon, is the vastness of space itself. Rocks tell tales of different worlds lost in the mists of time: other shores, other creatures, other climes…

Where the land ends…
In the north of the St Vicent coast, old rocks rise up which geologists date from the Palaeozoic era (544 to 245 million years ago). There is argillaceous schist and grauwacke (such as on the beaches at Odeceixe and Castelejo). There are also limestone, quartzite and other lithological formations. The fossils of creatures who lived in these strange, far off Palaeozoic worlds appear frequently. Petrified witnesses of habitats, forgotten over the passage of countless ages when species now extinct were abundant.
Produced by long, gigantic tensions, the rocks are generally distorted, fractured and metamorphosed (such as those between Baia dos Tiros and Odeceixe). These distortions are frequently chance occurrences, the tops having been lopped off by the intense erosion that took place during the Permian age (290 to 245 million years ago). The Palaeozoic lands, just like the Mesozoic that appear to the south, are crossed by numerous lines of igneous rock (visible in the enclosing schist and grauwacke on Murração beach as well as in other areas). Veins, at times, related with the connection of the solid sub-volcanic rock of Monchique.
The Mesozoic rocks (245 to 65 million years old) are supported by those of the Palaeozoic in clear angular discordance (good examples of this can be seen on the beaches at Telheiro or Ponta Ruiva). The grés de Silves (‘Silves sandstone’) are the oldest Mesozoic lithologies. These rocks, from the Triassic period (245 to 208 million yers old), have left sediments in various environments. They change with time, forming new rocks, species become extinct and new ones appear…
Continental sandstone flourishes (shown by deposition conditions in a semi-arid climate), evaporates as well as other rocks of transitional environments (from lagoons or estuaries), limestone from clearly marine environments and even basalt proving that there has been volcanic activity. In the Carrapateira, tufts and volcanic agglomerations can be found probably connected to the opening up of the Atlantic ocean.
During the Jurassic (208 to 145 million years ago) and Cretaceous (145 to 65 million years ago) periods, as well as the beginning of the Miocene period (24 million years ago), sedimentation went on in aquatic environments (from the coastal and/or transitional shelf). Limestone and dolomite rocks were deposited, at times with a strong earthy influence. After the Pliocene era (5.3 to 1.8 million years ago), the sea withdrew from what is today the Algarve.
During Würm (80 to 10 thousand years ago), the sea would have been a hundred metres lower than its current level and, in the previous glacial periods, the fall would have been even more significant. These cold periods are connected to the volumetric increase of the polar glaciers and the fall of the average level of the oceans. In the warm, interglacial periods, the water level rose due to the thaw, flooding the continent as can seen from the end of the Würm glaciation up to the present day. The variation of the average sea water level created various raised beaches or marine terraces (such as in the Carrapateira area or Cape St Vicent). The shelf erosion, which extended along the whole coast in a 5 km wide strip (only interrupted by the drying up of the main water courses), was created in just this way.
The shelf often lies bare, but not always. It is generally covered by a thin film of sedimentary deposits (as at Carrapateira or Vila do Bispo): sand and small pebbles either smooth or rough. These are sediments that appeared as solid dunes (those between Dornas and Pedra do Cavaleiro, for example) or the sand of raised beaches (such as the surface of the erosion at Cape St Vicent).

Costa Vicentina © João Mariano

…The sea begins
The waters are wild, in their constant activity, their erosive action goes on
ad eternum. The waves that clash against the coast, smashing on stone, or the currents an tides that modify the rocks express themselves in continuous meteoric and transporting actions. Água mole em pedra dura… tanto bate até que fura! (Gentle water on stone drips many a day… in time that stone will wear away!)
Erosion occurs due to wave action, above all due to strong winds and, to a lesser extent, tides. This is in spite of other factors being involved in the erosive process: dissolution, the impact of spray or biological activity. Erosion is particularly intense during storms, when huge waves are repeatedly thrown against the coast. The violence of the sea reaches its height in the months during the equinoctial storms. The waves batter the hills, due to the stormy winds of the western quadrant, with the waters leaping more than 60 metres into the air. The meeting of tempestuous waves and rocks reaches hundreds of tonnes per square metre. The blast can be heard more than 10 km away. It is on such occasions that the power of water can be best felt, its capacity to mould the coastline, to sculpt the stone and make it ‘wear away’. The efficacy of the wild waters, their mechanical action, is made possible by the erosive effect of the broken up detritus (sand, pebbles and blocks) and added to by chemical erosion which makes itself felt, above all, in the carbonated rocks (limestone and dolomites). The action of the water, the digging away, works primarily at the foot of the cliffs, in the region between by high and low tide, which is dug out by the waves. The attack, whether tame or furious, of the Atlantic waves creates steep cliffs, where the cornices are barely developed or even no-existent. Differential erosion, however, also leads to arches (such as at Caixões, between Carrapateira and Vila do Bispo), exhumed veins (the so-called mata-cães, literally ‘dog-killers’) or caverns (like those Gralheiras, near the beach at Amoreira). These modulations are the result of the digging which normally develops along the weak surfaces of rocks (fractures or veins).
The diverse needles, towers and rock islands that are often to be seen along the coast also bear witness to the erosive action of the water. Separated from land by the rapid advance of the sea, these growths are hard reliefs that, as the name indicates, are most resistant to erosion. The Pedra da Galé, that extends from Pontal da Carrapateira to the east, is only one example among many.
Immediately to the south, there are various small islands such as Pedra de Valverde, Ilha do Forno, Pedra da Manteiga, Pedra do Cavaleiro and Pedra da Gaivota. The áreas where a great number of hard ‘islets’ can be found stretches from Ponta da Atalaia to Ponta da Arrifana and from Pontal da Carrapateira to Ponta do Telheiro. The water, that great sculptor, is also responsible for zoomorphic and anthropomorphic forms as well as other stone carvings. All along the rugged coastline, there are narrow “rocky beaches”, at the foot of the slopes, or more extensive areas, at the mouth of waterlines. Some re-entrances have been closed by coastal barriers and blocked (Praia da Bordeira, for example), and are the source of grater and lesser fears.
The Cape St Vicent coast still enables us to (re)connect with the former Earth, to find the elements in its ancestral purity and liberty. The clash of the waves in meeting the slopes or the breath of the wind in the whirlpool. Sounds of a land which is blurred with the sea in a picturesque panorama of water and rock. They move, feel, hear and see! The Cape St Vincent coast is an invitation for eyes to see.

Costa Vicentina © João Mariano
Costa Vicentina © João Mariano

LUGARES pouco comuns - Uncommon places (2000)
Photographs by: João Mariano
Texts: João Mariano (Uncommon places) e Pedro Cuiça (Costa Vicentina – Land, sea and immensity)

3 comentários:

Clara Queiroz Lopes disse...

Caros Pedro Cuiça e João Mariano,

Andava à procura de grutas na costa Vicentina e cheguei aqui...Há imagens de grutas que gostava de identificar. Podem ajudar-me? Gostaria muito, muito de visitá-las.
Meu mail: lugares@sapo.pt

Agradeço a gentileza de me contactarem. Clara Queiroz Lopes

Clara Queiroz Lopes disse...

Por favor indiquem-me o vosso contacto. Preciso de identificar as grutas da costa Vicentina fotografadas pelo Mariano. Obrigada. Clara Queiroz Lopes

Pedro Cuiça disse...

Olá Cláudia
As minhas desculpas por só agora responder. Pode entrar em contacto comigo através do e-mail espeleo.desnivel@gmail.com