Porto Santo it’s a geoparque aspiring to the classification of European Geopark, the acceptance of the application from Porto Santo to the European Network (EGN) and Global Network (GGN) of Geoparks is, however, the reach of several intermediate stages, namely the recognition as Geoparque Regional and National Geoparque.

Only with a thorough knowledge of what is an European Geopark can a decision be made, with reason and conscious, for all that, inevitably,  everyone as to be involved in (population, authority, private business).

This project is to achieve the following objectives:

• Meet and maintain the geological heritage of the island of Porto Santo, recognized by the City Council as an added value to the County;
• Promote and enhance this heritage with the local populations and the general public;
• Sensitize the school population to the importance of natural heritage in general and geology in particular under the Conservation of Nature;
• Promote sustainable tourism of quality, based on natural and cultural values of the region;
• Enhance and encourage the development of traditional economic activities related to natural heritage and tourism;
• Develop and implement strategies for tourism and scientific dissemination of Porto Santo.

Geosite 1 – Columnar Disjunction of Pico de Ana Ferreira

Ana Ferreira Peak is a relief produced by differential erosion due to the hardness of the mugearite rock that constitutes its core. It was formed from magma of intermediate composition in a magma chamber underlying the peak. Mugearite is a volcanic rock distinguishable from the surrounding more altered basalt by its grayish tone due to a more differentiated stage inside the magma chamber, becoming enriched in silica and alkalis such as Na and K.

The prismatic or columnar disjunction found in Ana Ferreira peak is due to the slow cooling of magma that gradually retracted in all directions, giving rise to a geometric pattern of thin fractures. The regularity of this pattern, ideally perfect hexagons, is a function of the homogeneity of the rock’s composition and of the gradient of heat loss.

Geosite 2 – Dykes which intersect dikes (Morenos)

The N and NW cliffs of the island have a large complex grid of magmatic rocks. The basalt and trachyte dykes exhibit prismatic disjunction, locally called “navalheira stone” and they intersect each other in a sequence of magmatic intrusions.

In this geosite we can also observe rootcasts inside the eolinanites. These are calcified structures resulting from cementation of calcium carbonate around the roots of existing plants in the old dunes. The transpiration of plants provides a mechanism for absorbing water from the soil through the roots, and for receiving nutrients and other dissolved minerals. This calcium carbonate, CaCO3, from fragmented shells of marine organisms, precipitates and tubes form around the roots, which stay in place even after the plant is dead.

Geosite 3 – Pillow lava (Zimbralinho)

Pillow lava is a lava flow typical of under-sea volcanic eruptions. This designation is due to its approximately spherical section, similar to cushions. They form not only in deep sea but also whenever the lava flow above water comes into contact with the seawater.

Descending to the Bay of Zimbralinho, spheroidal disjunction can also be seen as a result of the fragmentation and separation of the curved onion-like layers of the magmatic rock due to weathering processes. Prismatic disjunction can also be seen in the Bay of Zimbralinho as in Ana Ferreira Peak.

Geosite 4 – Fossil coral reefs and galleries on the Ilhéu da Cal

The Low or Cal Isle is the largest of Porto Santo islands, where the extractive of limestone industry began in the XVIII century for the manufacture of lime, a strategic material used in the construction of various types of masonry buildings.

The stratigraphic sequence discloses submarine lava flows, volcanic ash layers and thick layers of limestone formed in coastal reefs in tropical conditions at a depth of not more than 40 meters.

Geosite 5 – Lava tubes (Ilhéu de Cima)

The lava tubes which can be found in parts of this isle are locally referred to as the “Sun Stone” because of the radial prismatic disjunction it presents. These tubes are formed when lava flows from the point of eruption and slides at high temperatures along the surface in the form of tubes or channels. In contact with the much colder air, these tubes solidify creating a crust that allows the lava to keep its temperature and flow inside the tube this way reaching longer distances. As the cooling progresses, the lava retracts and sets up a geometric pattern of fine fractures that give rise to the appearance of prismatic structures whose alignment defines the direction of cooling, in this case from the outside to the inside of the tube.

Geosite 6 – Cabeço das Laranjas (Ilhéu de Cima)

On the Eastern tip of the North-Western part of the isle, the “Cabeço das laranjas” presents a spectacular outcrop of round laminar fossils produced by red algae (rhodoliths) locally known as “oranges” because of its resemblance to the fruit. This is an unusually massive accumulation of large rhodoliths along a layer 6-meters thick, with intercalations of volcanic ash and some fossils of corals, sea-urchins (Clypeaster), Pectinidae and other molluscs.

Geosite 7 – Eolianites (Serra de Fora)

The eolianites are designated as Eolianitic Formation and cover about 1 / 3 of Porto Santo Island. This formation from the Quaternary age show’s a yellow-white in colour and is composed mainly of shell fragments of marine microorganisms, molluscs and calcareous algae. In these old dunes there are also fossils of terrestrial gastropods (snail shells), bird bones and rootcasts.

Geosite 8 – Salão (bentonite) -Navalhão-Baião

The bentonitic clay deposits are an alteration product of the Old Complex of the island whose age dates from 10-16 million years ago. These green clay formations result from intensive weathering of submarine breccia. A net of later intruded dykes preserved this clay unit from erosion. Locally known as “salão”, these clays were traditionally used to cover roofs to keep inside the house cool in summer and warm and dry in winter.

Geosite 9 – Fossil-bearing layers of Lombinho

Located in the North-East of the island, several fossiliferous layers date from the Middle Miocene (approximately 14 million years ago) outcrop inside a thick sequence of volcano-sedimentary facies. These sedimentary sequences suggest shallow deposition along a paleoenvironment of moderate to high energy with a large variety of marine fossils such as isolated and colonial corals, rhodoliths, molluscs (Pectinids, Ostreids), sea-urchins (Clypeasterids), among others.

Geosite 10 – Columnar Disjunction of Pico Branco

Trachyte and rhyolite volcanic rocks, of light-gray color, can be found in the NE of the island. On the White Peak we can find a huge prismatic disjunction ,locally called as “Rocha Quebrada” (broken rock), in which the path Pico Branco-Terra Chã was carved. The area of Pico Branco and Terra Chã is part of the European Network of Sites of Community Importance – Natura 2000, Habitats Directive, because of its endemic flora and fauna (terrestrial molluscs, i.e. snails).

Geosite 11 – Hyaloclastites of Pico da Cabrita

These rocks of submarine volcanic origin consist of angular fragments of lava of variable size and color, with a vitreous and porous texture due to the sudden and explosive contact with seawater; while still hot they consolidate into a colourful volcanic breccia.

Geosite 12 – Dykes of Porto das Salemas

The steep cliffs of the N and NW coast present volcanic pyroclastic formations represented by tuffs and breccias. The tuffs are cut by a significant network of dykes, conduits that fed a major field of surface volcanoes, long eroded.

The dykes are magmatic rocks of tabular shape, resulting from in-fill by lava that did not extrude but, instead, consolidated inside deep fractures in older rocks. Their attitude and size vary, with thicknesses ranging from a few millimetres to a few meters. Their thickness is not always constant and they sometimes branch out following a more-or-less irregular pattern in the fractures opened by volcanically induced pressure.

Geosite 13 – Eolianites of Fonte da Areia

In this geosite large accumulations of biogenic carbonate sand belonging to the same Eolianitic Formation as in Serra de Fora have hardened into eolianites. Eolianites are the legacy of the last “Wurm” glaciation, which occurred between 100 and 10 thousand years ago. Below the eolianite there is a clay unit of probable lacustrine origin, which is in direct contact with an angular unconformity along an ancient topographic surface carved upon much older volcanic dykes and lava flows.

Geosite 14 – Carbonated fossiliferous sands of Porto Santo’s beach

The golden-yellow sands of Porto Santo are unique among all other mainland and island Portuguese beaches since they result directly from erosion of the eolianitos that outcrop on several sectors of the island. The sand grains are mainly constituted of microfossils and small shells, red algae and other fossil fragments of marine organisms that developed thousand of years ago in the shallow waters that surrounded the island, during the last glaciation (Wurm).

More information: http://www.geoparkportosanto.com/en/