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Mid-Atlantic Ridge

Date of Submission: 06/06/2017
Criteria: (vii)(viii)(ix)(x)
Category: Natural
Submitted by:
Permanent Delegation of Portugal to UNESCO
Coordinates: N29 - 49 W20 – 40
Ref.: 6231
Word File

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Definition and delimitation of property

The Mid-Atlantic Ridge (MAR) is a volcanic mountain range that rises from the Atlantic abyssal plain, extending from the Arctic (Gakkel Ridge) to the Antarctic (Bouvet Triple Junction) across the two hemispheres, ranging more than 16,000 km. Ocean ridges such as MAR are highly complex and dynamic geological systems, which develop at the juncture of different tectonic plates. In this case, MAR is the longest mountain range in the world, with more than 90% of its length submerged. Its depth averages 2,500 meters (m), but occasionally the axial zone of this system emerges above sea level, as in Iceland. MAR was discovered in the mid-nineteenth century, when the first submarine cable was extended between North America and Europe. Over time, this underwater mountain range has been described, but only in the 1960s it was possible to start mapping it in all its extension. However, the detailed description of some sections of the MAR has just recently been possible, due to an increase on technological capacities to map the sea bottoms. For this reason, and because of its vastness and depth, a large part of MAR is still to be comprehensively mapped and studied.

The section of the Mid-Atlantic Ridge that is included in this proposal is enclosed by the continental shelf beyond 200 nautical miles, under the ratification of the UN Convention on the Law of the Sea (UNCLOS), and their submission to the Continental Shelf Limits Commission (CLCS) to the United Nations, delivered on May 11, 2009 by Portugal. The selection of this area stems from the geological consistency demonstrated during the proposal application for the extension of the continental platform around the Azores (map 1), responsibility of the Task Group for the Continental Shelf Extension (EMEPC), causing the conformation of this area to result from the presence of MAR. The zone includes the 9 inhabited islands of the archipelago and its 596 islets, the territorial waters, the subarea of the Azores of the Portuguese Exclusive Economic Zone (EEZ-Azores) and the contiguous extended platform.

In the Azores, the MAR is integrated in the platform or Plateau of the Azores, a geological structure of large, thick triangular mode setting (approximately 400,000 km2), delimited by the bathymetric of 2,000 m that rises from the surrounding abyssal plain containing not only the islands of the archipelago, but also numerous seamounts, with an average density of 3 seamounts per 1,000 km2. Some of these elevations, now submerged hundreds of meters deep, were emerged in the past (from thousands to millions of years ago), forming islands and, for this reason, exhibit flattened tops caused by coastal erosion (guyots). The sinking of these seamounts, result from the phenomenon of subsidence and other factors that shaped the geographic evolution of former islands of volcanic origin.

Within the context of the extended area that constitutes the property of the indicative list, the following relevant areas are highlighted:

Seamounts of the Meteor Complex: This area is a group of seamounts located approximately at 300 km south of the Azores and 1,500 km NW of the African continent. The northern polygon line that integrates this marine protected area is distant 335 km of the city of Horta (181 nautical miles) and 285 km from the city of Ponta Delgada (154 nautical miles). Although relatively close to the archipelago of the Azores, it is a remote and secluded complex, having several of its seamounts a stub-shaped plateau, a sign that some of the structures that constitute it must have been islands in the past. This set of seamounts consists of Pico-do-Sul (located in the Azorean sub-area of the Portuguese EEZ), Tyro, Atlantis, Plato, Cruiser, Irving, Hyères, Great Meteor, Small Meteor and Closs, located outside of the Azorean subarea of the Portuguese EEZ, but included in the continental shelf. The origin of this group of seamounts it’s considered to be connected to the eruptions associated with the New England “hot spot”. The Cruiser Plateau it’s estimated to have formed some 76 million years ago, when the volcanic activity connected to the movements of the African plate initially moved north, during the late Cretaceous and early Cenozoic (in the case of Plato, Atlantis and Tyro), and then south to the Great Meteor, at the end of the Cenozoic. Recurrent volcanic activity probably occurred until about 20 - 30 million years ago, in this zone. The Pico-do-Sul seamount, located at 34 ° 55 'N / 27 ° 26' W, is the closest to the archipelago, having a minimum depth of 1714 m and belongs to the Azorean sub-area of the Portuguese EEZ. The Atlantis Seamount Complex is formed by different elevations, but has a common base about 2400 m deep. Located about 40 miles away from the Azorean subarea of the Portuguese EEZ, 34° 40’ N / 27° 30’ W, the Tyro Seamount has a minimum depth of 1370 m. The Atlantis is the most western seamount. Plato, located south of the previously described seamounts, has approximately 110 km in length and a minimum depth of about 580 m, being aligned in an E-W direction. The Cruiser Plateau located southeast has a minimum depth of 590 m and a length of approximately 70 km. At southwest stays the Irving seamount, with an oval shape and a length of 100 km, having a flattened top. It rises from the abyssal surface up to 250 m deep and is located close to the meridian 32° N and the parallel 28° W. Continuing southwest, is the Hyères Seamount, which has an approximate length of 100 km and a minimum depth of 330 m at 31° 20' N/28° 50' W, raising its northwest side abruptly from the ocean floor. Further south, lies the Great Meteor, a large elliptical seamount with a flat surface, i.e. a guyot, with approximately 1500 km2, rising from 4200 m up to 270 m below sea surface. In addition, there are two other smaller hills southwest of the Great Meteor Seamount, namely, the Little Meteor Seamount, located at 29° 40' N/29° W and the Closs Seamount, at 29° 20' N/29° 10' W. Within the Seamounts of the Meteor Complex, the multidisciplinary study of the Great Meteor has become a long tradition. Several studies have shown there is a complex ocean circulation pattern in the area, which is known to contribute to the formation of vortices, known as eddies, which disperse to other areas of the Atlantic. In the Great Meteor, stands out a tidal cyclical pattern with high spatial and temporal variability, particular through formation of processes to generate tidal waves, with a horizontal and vertical circulation cell system. In the superficial layers, there are density anomalies associated with the formation of anticyclonic circulation phenomena, with speeds up to 6 cm/s, extending its influence out of the seamount area. The anti-cyclonic vortex at the top of the Great Meteor enhances the aggregation of zooplankton communities, micronekton and even small fish which, in turn, serve as food for other species, and contributes to the aggregation of living predators and fauna. The substrate of this habitat is colonized by sponges, gorgonians, cold water corals and sea urchins. Despite the geographical isolation and the lack of nutrients in this area of the subtropical gyre of the North Atlantic, there is a great biological diversity. The endemism is relatively low in fish, but high in the small fauna inhabiting the sediments, particularly copepods and nematodes. The communities that inhabit the slopes of these seamounts are the largest environmental group. In biogeographical terms, the fauna associated to the seabed in this area, consisting in particular of invertebrates and fish, has a transoceanic distribution in most species, while the rest come just from the east or west of the Atlantic or the adjacent continental areas or the areas of open sea. Still invertebrates linked to the sediment exhibit a confined oceanic distribution seamounts and islands. The fauna of this area exhibits greater affinity with the margins of the European and African continents of the Northeast Atlantic than to the American fauna as an example of what happens to the archipelagos of Macaronesia. In the Mauritanian province, fish are more typical than invertebrates, finding the latter associated with the Madeiran, Lusitanian, Mediterranean and Azorean areas. Biogeographic and paleontological studies suggest the existence of a parallel pattern in the biogeography between the Meteor seamounts and the Azores, where both have slopes that can be characterized as a mixture of faunas with different backgrounds. Considering the fisheries resources, in this complex of seamounts, there are at least 53 fish species of commercial interest described, of which abound some pelagic species such as Chub Mackerel (Scomber japonicus), Blue Jack Mackerel (Trachurus picturatus); other demersal, as Splendid Alfonsino (Beryx splendens), Forkbeard (Phycis phycis), White Swordfish (Lepidopus caudatus), Black Scabbardfish (Aphanopus carbo), Atlantic Wreckfish (Polyprion americanus), European Conger (Conger conger), Common Mora (Mora moro), Blackbelly Rosefish (Helicolenus dactylopterus); or benthic, as the Trumpetfish (Macrorhamphosus scolopax), Boarfish (Capros aper), and the Swallowtail seaperch (Anthias anthias). In this area, are also abundant the deep-sea sharks of genus Deania, Centroscymnus and Centrophorus. The area is used for large pelagic fishing such as tuna and swordfish and demersal fishing, having already been registered the exploitation of crustaceans (shrimps and crabs). Regarding mineral resources present in this complex, polymetallic nodules of manganese, copper, nickel and cobalt have been described for Plato Seamount. The area has high potential for mineral exploration and has habitats with high sensitivity that host species with high biotechnological potential and relevant value for fishing.

Condor Bank: The Condor Bank is a seamount that was discovered in the 1960s, located at 17 km west-southwest of the island of Faial. It has approximately 1800 meters high, 39 km long and a width of 23 km, extending from 185 to 2003 m deep. It is a volcano with an elongated shape, east-west orientation, flat top, and signs of a recent emersion (at the end of the last major glaciation), which is also confirmed by the presence of shingle in its west side (shallower area). In that bank, stands out the presence of coral gardens, discovered in 2006, sponges aggregations and sediment areas harboring gorgonians, sponges and other organisms. The area has been used as a heavily fished zone, given the high density of several species with commercial interest (demersal and pelagic fish), although there is evidence that the current density of commercial fish has decreased due to a high pressure by fishing. More recently, the area has been subject of intense study by the scientific community, and its availability restricted by a Regional Decree, with the cooperation of the fishing industry, including fishermen and ship owners. The Condor Bank is a representative of the Azores Seamounts ecosystems, being an area of great interest for fishing (demersal, large pelagic and tuna) as well as for maritime tourism activities (diving with sharks or big game fishing) and for scientific research.

Princess Alice Bank: The Princess Alice Bank is located 90km southwest of the island of Pico. Its top is at 35 m deep in the west area of the bank. This is an area that is heavily used for fishing, including through the use of bottom longline, surface longlines and tuna fishing (using the jump-and-stick method of fishing with live bait). Besides being important for fishing, this area has a high significance for the maritime tourism activities such as pelagic dive in open sea. The quadrangular area with sides that are 5 nautical miles apart to either side of the shallower point, is defined as a protected area. This site has special interest for elasmobranches observation (manta rays and pelagic sharks) as well as species like Seriola spp. (Greater amberjack), Sphyraena viridensis (Yellowmouth barracuda), Thunnus spp. (Tunas) and Katsuwonus pelamis (Skipjack tuna). Although this area constitutes a typical pelagic habitat where many species are aggregated, the top of Princess Alice Bank has also a characteristic community of coastal areas on the high seas, consisting in this way a single case in the Azores.

Sedlo Seamount: it is located 300 km NE of Graciosa Island. This is an isolated underwater volcano, which lies on the ocean floor at 3000 m deep and ascends in the water column up to 660 m below the ocean surface. It has an elongated form (75x30 km) and the top is a plateau table with three peaks. The complex movement of nutrients in the water column supports a diverse fauna, which can be considered abundant in oceanic context. Important aggregations of Hoplostethus atlanticus (deep-sea perch) were confirmed in the water column and also the presence of a diverse benthonic fauna, consisting of sponges, corals and gorgonians.

Altair Seamount: The Altair seamount is located in the Atlantic, relatively close and to the NW of the Azores. Its location, west of the Mid-Atlantic Ridge (MAR), indicates a geological formation previous to seamounts integrated in that divergent pole of active tectonics. The Altair seamount rises from abyssal plain with more than 3500 meters deep, the hillsides have steep slopes, and the summit situated 1175 m below the ocean surface. The biological characterization of this marine area has gaps, but the occurrence of vulnerable species, such as Etmopterus princeps (Great lanternshark) and other deep-sea fish, is confirmed. There is increased likelihood of endemic species, due to the geographical isolation of the area and given to its greater antiquity regarding the MAR.

Antialtair Seamount: The Antialtair Seamount is located NE and relatively close to the Azorean archipelago. Its position east of the MAR indicates an earlier geological formation in comparison to the seamounts in the divergent pole of active tectonics. Rises from the abyssal plain with depth exceeding 2000 m and the summit located 1032 m below the surface of the ocean. There is little information available on the biological communities in this area, but the occurrence of Hoplostethus atlanticus (Deep sea perch) has been confirmed. This kind of species usually form clusters with large numbers of individuals and often occurs near the seamounts crest. The species H. atlanticus, very sensitive to direct pressure from commercial fishing, is generally considered a vulnerable species. The Antialtair Seamount is an isolated geological structure with hard substrates that surface from the sediment layer of the abyssal plain. Its old formation increases the probability of occurrence of endemic species and marine habitats of great biological interest.

MARNA (Mid Atlantic Ridge North of the Azores): Located north of the Azores, this Marine Protected Area comprises a vast expansion of seabed and underwater relief near the Mid-Atlantic Ridge, in a place that is distinguished by high density of seamounts. It is a representative portion of the geological characteristics of this region, which is an active center of oceanic crust expansion, located in the divergence zone of the Eurasian and North American tectonic plates. The concerned marine region has a great variety of species and natural habitats as a result of the complex topography of the geological substrate, and its interference with the movement of water masses. The benthopelagic communities include some species of deep-sea sharks that are part of the OSPAR list, namely Centroscymnus coelolepis (Portuguese dogfish), and Centrophorus squamosus (Leafscale gulper shark).  

Dom João de Castro Bank: located 65 km from the city of Angra do Heroísmo and 38 miles from São Miguel Island. Corresponds to a seamount that rises 1600 m in comparison with neighboring seabed and its top is currently around 13 m deep. This active volcanic building - with significant seismic activity - has a crater at the top with 450 m in diameter and about 28 m gap, where there is an important fumaroles’ field of low depth hydrothermal vents, with temperatures between 39°C and 83°C. The edge of the crater is partitioned submerged between 13 and 40-50 m deep being the most intense hydrothermal activity within this crater. This polygenetic volcano has formed an island - called "New Island" - upon volcanic activity during the year 1720 A.D.. In the meantime this island has vanished due to sea erosive action and due to the collapse of the volcanic cone.

The seabed and the waters around the Dom João de Castro Bank exhibit great biodiversity, with about 220 species identified. The dominant macroflora consists of a mat of Sargassum sp. and large pelagic fish are common in this area, being some species relatively common: Mobula tarapacana (Manta rays); Canthocybium solandri ("Wahoo"); Sphyraena viridensis (Yellowmouth barracuda); Kyphosus spp. (Bermuda sea chub); Katswonus pelamis (Skipjack tuna); and also shoals of Sarda sarda (Atlantic bonito). Despite the strength of the currents, this marine protected area is easily accessible by scuba diving. This, coupled with the wealth of geological and biological heritage, makes the Dom João de Castro Bank a place of great interest for the practice of underwater tourism and for support of educational activities within the Marine Sciences.

Within this area, and emphasizing the value of the inventoried property, a set of five visible events were selected from the MAR, included in the indicative list , that constitute an unique interest due to the fact that they represent unique and spectacular manifestations of this structure:

  • Portugal – Volcano of Pico Mountain: This elevation corresponds to a stratovolcano, geologically very recent, which last eruption took place in the year 1718 A.D.. It reaches a maximum altitude of 2351 m above sea level (the highest point of Portugal) and has a height of about 3500 m above adjacent sea, corresponding to the third largest polygenetic volcano in North Atlantic. At the top of the volcanic cone there is a crater with a pit crater type collapse, with a diameter of 550 m and a depth of 20 m, which stands a small lava cone, the "Piquinho", about 70 m high. This stratovolcano has sharp slopes in the higher part, while closer to sea level the flattened lava fields of basaltic pahoehoe lavas predominate, with frequent lava tunnels, as is the case of the “Gruta das Torres” which is the largest cave in the archipelago, with more than 5 km long. While in its branches there are about 210 secondary cones (mostly cinder cones), at the top of Pico Mountain there is a steaming ground type fumarolic field with maximum temperatures of 75°C.

In terms of mountain formation, this took place in three phases:

Phase I: corresponded to the building of a large volcanic cone, which have reached probably similar dimensions to the current cone. This phase ended with the collapse of the top of this primitive stratovolcano and the formation of a crater-pit type crater, with about 800 m in diameter and rim at an elevation of roughly 2050 m.

Phase II: volcanic activity on top of the stratovolcano focused on issuing openings located NNE of that crater, and extensive pahoehoe lava spills from these new eruptive centers have eventually completely submerged from that depression, which left only a sharp breakthrough slope in the south flank of the mountain and a slight flattened area at an elevation of 2050 m. As in the previous stage, it ends with a new collapse of the top of volcanic structure, giving rise to the current crater at an approximate height of 2250 m and displaced to NNE of the fossil crater.

Phase III: includes the formation of the lava cone "Piquinho" inside the current crater and moved to NE from the geometric center of this depression. The pahoehoe lava flows issued from this cone, in an "entrail lava" form, filling a substantial part of the crater, and overflowing to the E and SE edges of the crater. This last phase included also the opening of an eruptive fissure at the top of the mountain, after the creation of the “Piquinho” cone. From this eruptive fissure and associated secondary openings only lava splashing and basaltic slags with low dispersion relative to the fissure were issued from it.

As a result of the high altitudinal gradient, Pico Mountain is characterized by having a set of unique flora and fauna communities in the Azores, and generally well-kept. With increasing altitude either diversity or density of plant species decreases, but the vegetation assumes a particular interest. The Mountain is the only place in the archipelago comprising alpine habitats and where vegetation is subject to prolonged snow deposits. Regarding the fauna, some species stand out, like the Turdus merula azorensis (Euroasian blackbird), Motacilla cinerea patriciae (Grey Wagtail) and Fringilla coelebs moreletti (Chaffinch), as well as the botanical species in Table 1.

Table 1 - Most characteristic flora species of the Mountain.


Common name


Silene uniflora ssp. cratericola


Endemic to the Azores

Daboecia azorica


Endemic to the Azores

Calluna vulgaris

Common heather


Thymus caespititius

Cretan Thyme


Erica azorica

Azorean heather

Endemic to the Azores

Juniperus brevifolia

Azorean juniper

Endemic to the Azores

Ilex azorica

Azorean laurel

Endemic to the Azores

Vaccinium cylindraceum

Azorean blueberry

Endemic to the Azores

Myrsine retusa


Endemic to the Azores

Holcus rigidus


Endemic to the Azores

Deschampsia foliosa


Endemic to the Azores

Luzula purpúreo-splendens


Endemic to the Azores

Lysimachia azorica


Endemic to the Azores

    • Portugal – Deep-sea hydrothermal fields southwest of the Azores: This area is an alignment of hydrothermal fields located in the axial zone of the MAR, southwest of the island of Flores. The three main hydrothermal fields (Menez Gwen, 868 m deep; Lucky Strike, 1693 m deep, and Rainbow, 2318 m deep) are classified as nature reservations and are an inherent part of the Azores Marine Park. These areas are also classified by the OSPAR Convention and as Natura 2000 network, for its exceptional natural value. This MAR section also covers other hydrothermal fields, such as Menez Hom and the Saldanha Mount. These hydrothermal regions are unique geological environments, within the deep ocean context, characterized by extreme temperatures, pressure and chemism, and presenting chimneys that emanate hydrothermal fluids characterized by their high temperatures (up to 340 °C) and high concentrations of methane (CH4) , hydrogen sulfide (H2S) and heavy metals. Biological communities that inhabit these hydrothermal vents are physiologically adapted to these extreme conditions, and settle all their ecology into the energy of hydrothermal fluids. Primary producers do not depend on the energy of sunlight to produce organic matter from carbon dioxide, like other ecosystems of the biosphere. Chemosynthetic microorganisms serve as food for mussels, shrimp and other species that are densely aggregated around hydrothermal vents. Here, the biomass can reach a value of 20 kg/m2, which makes the deep-sea hydrothermal fields’ true biological oasis compared to the surrounding abyssal environments: the endemic rate of hydrothermal fields in this region is very high, thereby increasing its intrinsic natural value. These areas include mineral accumulations with very high concentrations of polymetallic deposits and rare sediments, result of the precipitation of the chemicals brought by hydrothermal fluid to the surface of the seafloor. A list of species for these areas can be found at http://doi.pangaea.de/10.1594/PANGAEA.769944.
    • Portugal – “Algar do Carvão”, Terceira Island: The “Algar do Carvão”, located in the central area of Terceira Island, corresponds to a volcanic chimney about 80 m deep. The mouth of the algar has dimensions of 17x27 m and gives way to a first vertical pipe with about 45 m gap. There follows a 18 m ramp, that corresponds to a gravity deposit mainly composed of rocks, result of landslides from the ceiling and walls of the algar. After this ramp, there is a new vertical slope, which ends in a pool with clear water, sustained by rainwater, and reaching depths of 15 m, that is almost completely dry in the summer in years of low precipitation. The volcanic cavity develops longitudinally for about 90 m according to a general E-W direction. The formation of the “Algar do Carvão” took place in two distinct phases: i) a part of the algar corresponds to the conduct of a cone of basaltic slag, which has been in activity for about 1700-2000 years ago and, ii) most of this volcanic cavity, such as the vaulted rooms located on the pond, is the oldest and most developed in trachyte lava flows, where there are charcoals fragments 14C dated with an age of about 3200 years. In addition to the geological aspects mentioned above, “Algar do Carvão” has the most exuberant, rare and beautiful stalactites and stalagmites of amorphous silica, existing in the volcanic cavities of the Azores which are recognized as speleothems of global relevance in the context of “Vulcanospeleology”: these speleothems reach approximately 1 m in length and 40 to 50 cm in diameter. The “Algar do Carvão” features a diverse fauna of troglobitic invertebrates endemic to some elements of the volcanic cone. The beauty of this algar also shows itself in the vegetable stand that covers the inside of the cone, which incidentally is a very characteristic habitat - a volcanic chimney. Although the plant communities develop up to 64 m below the mouth of the algar, life is present throughout the volcanic cavity, with the presence of algae and molds. On the perimeter surrounding the entrance of the algar, there is an arboreal community composed of species such as Ilex perado subsp. azorica, Erica azorica, Laurus azorica, Vaccinium cylindraceum, some fetuses as Blechnum spicant, polypodium macaronesicum, Culcita macrocarpa and Elaphoglossum hirtum and many bryophytes mostly epiphytes on the existing tree/shrub species. Then passes to an herbaceous environment, with Lysimachia azorica, Hedera helix, several Carex, Leontodon rigens, Luzula purpureo-splendens and Prunella vulgaris, as well as several species of mosses and liverworts. In the bottom, biodiversity lowers considerably and there are only a few ferns and mosses. Finally, in the shadows, there is only diatom and chlorophyta algae and molds left. In terms of fauna, of vertebrates, it is possible to observe different birds that seek refuge here. A night visit provides the observation of birds like the House Sparrow (Passer domesticus), Common Blackbird (Turdus merula azorensis) and the Chaffinch (Fringilla fringilla). There is no record of the presence of any vertebrate (including bats) inside the algar, apart from occasional dead rabbits, the fall in the algar. However, the algar has a considerable amount of cave-dwelling arthropods, with several identified troglobite species, most notably a spider whose main population in the world is limited to this cavity, Turinyphia cavernicola. Noteworthy, though, is the presence of several species of bryophytes which are included in the Red List of Bryophytes of Europe (ECCB), highlighting the Alophosia azorica, Calypogeia azorica, Dumortiera hirsuta subsp. hirsuta, Fissidens asplenioides, Radula carringtonii, Telaranea europaea, Tetrastichium fontanum, Tetrastichium virens. “Algar do Carvão is open to public visitors since December 1st 1968, although the first descent into the algar occurred in 1893.
    • Portugal – “Furna do Enxofre”, Graciosa Island: The “Furna do Enxofre” is the largest volcanic dome in Europe. It is a large and imposing lava cave located in the southeast side of Graciosa Island, 194 m long, 172 m wide and 50 m high in the middle. The cave is characterized by having a perfect dome shape ceiling, considered the largest volcanic dome in Europe, communicating with the outside through two openings arranged along a northwest-southeast direction. The cave interior possesses a cold water lake and a mud fumarole. The latter is characterized by releasing carbon dioxide that can reach concentrations considered dangerous to humans and are therefore subject to continuous monitoring. The release of methane, radon and hydrogen sulfide also occurs, being responsible for the smell that gives the name to this cave. Considered unique in the world, both in vulcanological terms and speleological value, its genesis is associated with an important effusive intracaldera phase, Hawaiian type, which involved the formation of a lava lake, which was drained through this cavity. The interior of the cave is visitable, and it’s reachable by a staircase of rare beauty and environment, built early last century. Currently there is an interpretation center of this rare geological structure, a support to visitors. In this cavity there is an endemic species of mite, the Galumna rasilis Pérez - Iñigo. At the entrance several species of bryophytes can be found and that are included in the Red List of Bryophytes of Europe (ECCB): Radula wichurae and Brachymenium notarisii mosses (Mitt.) A. J. Shaw, Cyclodictyon laetevirens (Hook. et Taylor) Mitt., Fissidens asplenioides Hedw., Tetrastichium fontanum (Mitt.) Cardot and Tetrastichium fontanum (Mitt.) Cardot.
    • Portugal – “Capelinhos” Volcano, Faial Island: This is the last terrestrial volcano that occurred in the Azores in 1957-58. The Capelinhos was the subject of the first detailed scientific description of a surtseyan type eruption, in this case benefited from the proximity of a lighthouse that was located in front of the place where it occurred. During the active phase of this phenomenon, national and international teams of renowned scientists made observations, maps, notes, chemical analysis, photos and footage, which allowed for the first time to describe this type of volcano. The surtseyan term, however, was set up following the Surtsey volcano in Iceland, which erupted in 1963, whose island currently includes the World Heritage List of UNESCO (under the ix criteria). The Capelinhos, at the west end of Faial Island, was active between September 27, 1957 and October 24, 1958, which created the latest Portuguese territory emerged, initially expanding the island to approximately 2.4 km2. Today, much of the material emanating from the volcano has been eroded and the new area on the southwestern tip side of the island is considerably lower. The ruin of the imposing lighthouse that existed on the site is now integrated into the interpretation center of this phenomenon and the geology of the Azores. This underground center is regarded as an infrastructure of great esthetic beauty and highly recognized educational and tourist interest. The fauna associated to this volcano is very poor, highlighting the presence of an endemic species to the Faial Island adapted to lava environments and whose population only occurs in this place, Gietella faialensis.

Brief history of the discovered property

The MAR was first detected in 1850 by Matthew Maury, who baptized the discovered MAR fraction, as Dolphin Ridge. In 1870, the oceanographic expedition of the HMS Challenger confirmed an accentuated decrease in depth in the Atlantic middle area, when assessing the location of transatlantic submarine cables. The existence of the ridge was then remotely detected by sonar in 1925, during a German scientific expedition. Later, in the 1950s, it was held the first effort to structure mapping, being its complex pattern of valleys and superelevations revealed and associated to large seismicity, particularly in the central valley of the mountain range, also known as rift. The MAR became widely accepted as evidence for the plausibility of Wegener's continental drift theory, which would later give rise to the theory, still in force, of tectonics plate. From the moment it was set the location and macro-structure of the MAR, and its geomorphological origin, it was possible to trace a structural link between geographically distant locations, but whose geological link became evident, since these areas were originated by geological processes associated with MAR. The Azores, the Jan Mayen Island, Iceland, the Rocks of St. Peter and St. Paul, the Ascension Islands, St. Helens, Tristan da Cunha, Gough and Bouvet are all direct and visible expressions of MAR.


The MAR began to form 200 million years ago when the future American, African and European continents, still formed the Pangea. As this great continent was separated in fractions based on three tectonic plates (Nubia, American and Eurasian) the Atlantic Ocean began to form. This process is continuous and the Atlantic remains expanding today; in the central valley of MAR, or rift, the boundaries between tectonic plates, new funds are formed, at an average speed of about 20 mm per year (in the region of the Azores), in direct proportion to the distance of the continental margins. As the plates are pulling away, magma, from a dozen kilometers below the ocean floor, rises to the surface, forming new seafloor. In this process massive volcanic events give rise to large structures, over time, which constitutes the very ridge, plateaus, such as the Azores, islands and seamounts. Hydrothermal fields linked to the rift are more direct and permanent expressions of this activity. Since most of the MAR is located more than 2000 m deep, most of these eruptions can't be seen. The areas under the influence of MAR are characterized by the occurrence of earthquakes of varying magnitude and relatively frequent. These events occur in epicenters located in the MAR, in the typical transverse faults of the range or nearby. In the Azores the process described above, associated to the presence of a hot spot, determined the formation of the islands that form the archipelago.

Habitats, species and significant ecologic processes

The emerged area of the MAR in the delimitation area of the Azorean Archipelago belongs to the biogeographic region of Macaronesia, a particularly rich in fungi, plants and animals area in Europe. The number of land and marine taxa (species and subspecies) is estimated to be around 8047, being 491 of these endemic. The total number of terrestrial taxa in the Azores is estimated to be about 6164 (approximately 6112 species), and 452 of these taxa (411 species) endemic. The animals are the most diverse organisms in endemism, with 331 taxa (Arthropoda = 266; Mollusca = 49; Vertebrata = 14; Nematoda = 2), comprising about 73% of terrestrial endemism. The percentage of endemic mollusks (44%) is also noteworthy. Vascular plants have 73 endemic species, the Fungi (including lichens) have 34 and both the freshwater diatoms and bryophytes including seven endemic species. With regard to marine organisms, 1883 taxa have been quantified, belonging to 16 phyla, but their actual number is much higher and can exceed the 3500 species. The total number of endemic marine species and subspecies within the EEZ-Azores is 39, most of which consists of mollusks (29 species). Many subtropical marine species and some temperate species (coastal or deep) present their distribution limited north or south of the archipelago, respectively. The coastal marine life in the rocky areas sporadically extends from it, suffering from the direct influence of sea action, through the intertidal zones, up to 50 m deep. Algae, barnacles, limpets, whelks and sea urchins create and model microhabitats where small invertebrates live and that go unnoticed to the naked eye. However in coastal sandy environments, biological communities are not as lush due to the high dynamism and lower productivity in these areas due to less abundance of algae; but, a few meters deep, there may be several communities dominated by bivalves and not segmented worms buried in sediments.

The superficial waters of the Azores are marked by the summer migration of large predators such as tuna, swordfish and marlin, several sharks, manta rays, turtles and whales, using the area to feed on shoals of small pelagic fish, krill, shrimp, squid and gelatinous organisms that, in turn, feed of the resulting zooplankton of spring productivity pulse.

It is known that migratory pelagic megafauna is associated to the chains of seamounts, probably due to increased productivity that these structures concentrate. In the Azores there are currently 9 seabird species nesting, on a regular basis, which also use the epipelagic zone for food, such as the five sea turtle species, three of which are common.

In the mesopelagic and bathypelagic environment there are amphipods, small crustaceans, pteropods, squid, shrimp, gelatinous organisms and fish, highly specialized, known to be red, silver or black, by its bioluminescent organs, large and sharp teeth, and pending head barbells. The composition and ecology of these communities are poorly understood but it is known that, in the region, over 120 species of fish and about 60 species of meso and bathypelagic cells can be found. Some of the fauna that lives in the water between 500 and 1000 m deep do massive daily vertical migrations, reaching the surface layers of the ocean at night, where they feed on plankton, and go down at dawn, where they digest food and minimize predation of the great epipelagic. This fauna is essential for the ecology of the islands and seamounts slopes. The deep pelagic organisms, including plankton, when dragged by currents against the seabed constitute an energy source, vital for many predatory demersal fish, living in the region, including many commercial species.

In island platforms stands of animals that feed on suspended matter (particles, phyto and zooplankton) can be found. However the tops of low depth seamounts, separated from islands, are colonized by a transformed coastal fauna, with less diversity. In rocky environments of islands and seamounts slopes, aggregations of sponges, gardens and cold water coral reefs (gorgonians, black and hard) structure complex three-dimensional habitats, oasis of biological activity, where invertebrates and fish feed, reproduce, recruit and find protection. Nevertheless, sedimentary biotopes are characterized by detritivores organisms such as sea cucumbers, anemones and stalked sponges, which feed on plankton and particles carried by bottom currents.

In bathyal middle zone (1000 - 2000 m) up to 18 biotypes were inventoried, with coral gardens, aggregations of sponges, echinoderms aggregation, multispecific stands of corals, sponges and echinoderms. In the inferior bathyal zone, covered with seabed sediments, the coral gardens are sparse, as aggregations of sponges, and may also meet biotopes dominated by crinoids and starfish.

Exploitation of natural resources

The inhabited areas that are part of the MAR are political regions of coastal (such as the Azores and the islands of St. Helena and Tristan da Cunha) or island states (as is the case of Iceland). In the vicinity of these islands, historically isolated, marine resource exploitation processes have developed, with a more or less crafty nature and considered of low intensity. The fishing activity is undoubtedly the socio-economic sector of major importance for the people who inhabit these places; fishing is exercised on the geological structures which are part of the MAR and the developed technology is adapted to the natural characteristics that the structure gives to these regions. By their nature, these remote areas operate as a point of concentration of migratory species (whales, turtles and sea birds, pelagic sharks), which has a central interest for the development of economic activities related to ecotourism and observation of marine wildlife. Beyond the areas of national jurisdiction, some fisheries with industrial characteristics are developed, including fisheries targeting deep-sea species. Currently, there has been a rising interest in exploration capabilities of minerals of high value in various areas of the MAR, especially associated with deep-sea hydrothermal fields, so it is important to ensure that these future activities are developed in a sustainable manner, safeguarding the unique natural values.

Justification of Outstanding Universal Value

The Outstanding Universal Value of MAR and the Azores, expressed in its emerged and submerged heritage, comes from the unique geological features that are a present testimony of Earth's history. The circumstances of the archipelago formation promoted the creation of unique structures and high interest.

Protection status in force in the property area

In the year that the 70th anniversary of UNESCO was celebrated, the General Meeting of this entity, on November 17th, approved the new statutes of the UNESCO International Geoscience Programme and Geoparks (IGGP-International Geoscience and Geoparks Programme). With the creation of this new program, the first to be approved in the last 40 years, Geoparks were included in the European Network and Global Geoparks, as was the case of the Azores Geopark, joining now this UNESCO program.

The Azores Geopark covers 9 islands and the seabed of the archipelago, becoming all of it a territory under the UNESCO seal, which allows for better promotion and enhancement of the region. The integration of the Azores Geopark in the UNESCO Geoscience International Program and Geoparks, contributes to increase visibility of this region in the world, bringing more visitors to discover the Geological Heritage of existing excellence in the Azores and the cultural identity of the Azorean people, and to experience a diverse set of activities under the geotourism, such as visits to volcanic caves, mountain biking, thermal baths, hiking, climbing, canyoning or diving, among others, promoting the economic growth of the territory in respect its environmental values.

In the MAR region of the Azores there are several areas classified by international, national and regional legal instruments. All nine islands of the archipelago have Island Natural Parks (NIP), which include all terrestrial protected areas and marine coast. The Marine Park of the Azores (WFP) includes 11 marine protected areas beyond the territorial waters, and 4, which are located beyond the EEZ-Azores, in the extended platform. In the defined area there are 3 islands classified as Biosphere Reserves (Corvo, Graciosa, and Flores) and recently the region submitted a proposal to classify the island of São Jorge with this status. The marine and coastal environment of the Azores have 11 OSPAR areas (beyond territorial waters), 12 RAMSAR areas (a marine and other lagoons) and 41 areas of the Natura 2000 (15 SPAs, 23 SACs and 3 SCIs). The NIP aggregate over 180 hectares of protected area corresponding to 123 marine and terrestrial protected areas already classified by regional diplomas, as well as those established by international legal instruments, especially the Natura 2000 network.

The WFP includes marine protected areas that occupy approximately 11.14 million ha of total area. The four marine protected areas located specifically in the MAR includes the Mid-Atlantic Ridge North of the Azores (MARNA) and marine reserves Rainbow, Lucky Strike and Menez Gwen. There are 172 species of protected wild fauna occurring in the terrestrial and marine territory of the Azores (32 mammals, 73 birds, 7 amphibians and reptiles, 15 fish, 29 arthropods and 16 mollusks), see attached table.

Within the enclosed area there are 29 habitats listed in the Natura 2000 network, with 9 of them considered Priority Habitat by this international legal instrument (table attached). A vast area of the MAR is protected from the adverse impacts of bottom fishing gear due to the presence of vulnerable marine ecosystems (Regulation (EC) No 734/2008). The example property contained in the designation have the following protection statutes:

  • The hydrothermal fields located southwest of the Azores are classified as Sites of Community Importance of Natura 2000 (Lucky Strike, Menez Gwen and Rainbow). These hydrothermal sources are also included in the marine areas of the OSPAR Convention.
  • Due to its geological uniqueness, the "Algar do Carvão" is currently classified as a Natural Monument integrating the Natural Park of Terceira. This area is also part of the Special Area of Conservation of the mountain of Santa Barbara and Pico Alto (RN2000 - PTTER0017) and the RAMSAR Site (No. 1805 - Central Plateau of Terceira - "Furnas do Enxofre" and "Algar do Carvão"). The Volcano of Pico Mountain was one of the first areas classified in the Azores. Decree No. 79/72, March 8, determined that the Mountain of Pico Island should become an integral reserve. Due to its geological and ecological uniqueness, the Pico Mountain is currently classified as a nature reserve by integrating the Natural Park of the island of Pico. This area is part of a Natura 2000 Special Area of Conservation.
  • The "Furna do Enxofre" is located within the Caldera in Graciosa Island. This area is classified as Regional Natural Monument included on Graciosa Natural Park due to the presence of aesthetic values and the geological uniqueness of this complex. This natural monument is set in a wetland of international importance - RAMSAR Site.
  • The Capelinhos is inserted in Faial Natural Park as a protected area for the management of habitats or species. The Capelinhos volcano is also classified by international legal instruments, such as a Special Area of Conservation and Special Protection Zone of Natura 2000 and fulfills the criteria of BirdLife International as Important Bird Area (IBA). The surrounding marine area to Capelinhos volcano is classified in Faial Natural Park as a resource management protected area and as a reserve area for catch management (Decree No. 44/2014, January 10).

State of conservation of the property and potential maintenance strategy of the Universal Outstanding Value through legal protection and management attributes that communicate its value

In the case of marine area, the initial assessment report of the environmental status of marine waters of the Azores (SRRN (2014). Marine Strategy for the subdivision of the Azores. Marine Strategy Framework Directive. Regional Secretariat of Natural Resources. June 2014), carried out under the implementation of the Marine Strategy Framework Directive, and was considered that the majority of 11 environmental indicators defined in the policy were in good environmental status, and to this was drawn up a list of targets to be achieved by 2020, which will maintain this favorable conservation status. In the case of terrestrial examples, the areas considered in this list have been the subject of a conservation strategy and consistent and effective recovery, leveled by instruments of international, national and regional protection.

 Potential threats and implemented protection and management systems

The listed area has the following potential threats:

  • Overfishing: an unsustainable fishing practice can jeopardize the ecological balance of the area. In the Azores the management of fisheries resources is carried out under a common policy for fisheries of the European Union. On the other hand, a number of international organizations, such as NEAFC, ICCAT and ICES, currently demand fisheries management developed in the area, in a broader context.
  • Inadequate exploitation of deep-sea mineral resources: Private entities growing interest on mineral potential of various areas of the deep ocean around the Azores, especially in areas where hydrothermal fields are located, situated southwest of the Azores, can put into question the sustainability of these biological communities and the integrity of the geological heritage. However, the established scientific community in the Azores stays informed of these threats and collects information in order to provide the tools for authorities to allow, in the future, informed decision-making on how to conserve these places from an inappropriate exploitation.
  • Inadequate territory spatial planning: In the case of terrestrial properties, the inexistence of land use policies and territory planning could jeopardize the conservation of these areas. However, the Azores has a legal system of territorial management tools that safeguard the value of these properties. On the other hand, regarding marine properties, the Azores has been implementing maritime spatial planning policies, including through large areas that are home to ecological values and habitats considered of high regional and international value, as is the case of marine protected areas.
  • Tourism: Being undoubtedly an economic sector of great importance, which can help positively in the preservation of the property described herein and in their disclosure, the truth is that the practice of improperly ordered tourism practice may result in an increased pressure, which may, in certain circumstances, undermine the sustainability of the property concerned.

Property presentation and interpretation to visitors

The Azorean NIP present today an integrated and modern network of environmental interpretation infrastructures of natural heritage in all islands. In the specific cases of examples in this list, we highlight the following structures:

  • Volcano of Pico Mountain, Pico Island - The Mountain House (MH): Inaugurated in 2008, is an obligatory stop in Pico Mountain. Its main function is the registration and control of ascents, made through an authorization application delivered by visitors, according to the regulation. Situated in the upper limit where you can go by car, provides information on the geology, biology, history, climate and legal framework of the Nature Reserve of Pico Mountain, both in information panels, or in movie format, which can be viewed at the auditorium. The MH is complemented by a bar with panoramic views, where you can taste some local products while recovering from the effort expended on the way up or simply listen to the stillness of nature and enjoy the magnificent scenery that embraces the whole west coast of Pico and Faial Island.
  • Deep-sea hydrothermal fields southwest of the Azores - Azores Geopark: Covers the nine islands and the archipelago seabed, becomes all of it a territory under UNESCO seal, as in the year that marks the 70th anniversary of UNESCO, the General Meeting of this entity, last November 17, approved the new statutes of the International Geoscience Programme and Geoparks of UNESCO (IGGP-International Geoscience and Geoparks Programme). The Azores Geopark will be a key pillar of the disclosure of deep hydrothermal fields southwest of the Azores to the public.
  • “Algar do Carvão”, Terceira Island – Azores Geopark - Visitors Centre of “Algar do Carvão”: The value and merit that the association “Montanheiros” showed, throughout this long period of expeditions to the Algar, particularly with the opening of the tunnel and the construction of the road, did not go unnoticed by the owner of the land, whom the “Montanheiros” maintained a friendly relationship and who had verbally authorized all these actions. It is therefore not surprising that in November 30, 1973, a portion of that land, which housed the algar, was donated to “Montanheiros” by José Ataíde da Câmara and his wife. It was also donated a strip of land where the “Montanheiros” had ripped access, deriving from the Cabrito path, which facilitated the arrival to the "Pico do Carvão" and currently became a way of public domain. In 1987 it was possible to finish assembling a first fixed lighting system in the inside, powered by a generator. In the course of time, it built a house-support for reception of visitors and another to house the generators and storage groups. Currently this Algar is open during the summer for all those who want to visit, registering an annual demand in the order of several thousand visitors.
  • “Furna do Enxofre”, Graciosa Island – Visitors Centre of “Furna do Enxofre”: The “Furna do Enxofre” has a visitor center, from which the structure can be visited. The interior of the cavern is monitored in real time to ensure that the concentration of toxic gases do not jeopardizes the safety of users.
  • Capelinhos Vulcano, Faial Island – Capelinhos Interpretation Centre: The Capelinhos Intrepertation Center, opened in August 2008, was designed to preserve the existing landscape in the area affected by the eruption of the Volcano in 1957/58, in the western tip of Faial Island. Thus, the building, is wrapped in the volcanic sands, buried to the ground elevation before the eruption. The bold and invisible building is distributed between the old ground floor of the Capelinhos lighthouse and the respective support houses. In this space you can take a trip often virtual and interactive that, step by step, describes the geological phenomenon, opening up an important page in the scientific understanding of submarine volcanoes, through the pre, during and post Capelinhos volcano periods. The proximity of a unique landscape associated with one of the most recent eruptions of the archipelago, are factors that make an environmental and nature tourism as well as a tourism of culture and science. Through various exhibition and interpretative tools, the Capelinhos Interpretation Centre is a diffuser vehicle of scientific knowledge, which may be recognized as a science center and as a place of excellence for tourist attraction, with a mission to develop actions that provide exploration activities that enrich the experiences of those who visit. In the end, you can climb to the lighthouse, where you can enjoy this unique landscape. It was nominated for best European museum in 2012.

In addition to the infrastructure dedicated to each property, included in this list, the regional support strategy for tourism is organized in order to provide visitors with the fullest possible experience when it comes to contact with geology and biodiversity and the surrounding. It can therefore be said that a trip to the Azores is, above all, a visit to the MAR, with all its implications for the way that it shaped the culture and beliefs of the people who inhabit the islands and their history.

Criterion (vii):  represent remarkable natural phenomena and areas of exceptional natural beauty and aesthetic importance.

  • The hydrothermal fields represent exceptional structures in the ocean, sometimes at great depths, taking into account the extreme conditions of temperature and pressure, with chimneys emitting waters typically exceeding 300 °C and high concentrations of gases such as CO2, CH4 and H2S. These superheated water flows are rich in minerals such as sulfur, copper, gold and iron, which when in contact with the seafloor cold water precipitate and give rise to spectacular chimneys.
  • Algar do Carvão exhibits features and an unique environmental importance, especially because of the unique and lush speleothems, including stalactites and stalactites of amorphous silica of great rarity and beauty and reddish ferric veins that turn distinct the two inner domes: on the lagoon dominates the silica and the "stage" is dominated by ferric deposits. This pond, with other formations of the cave that surround it, brings an additional beauty to the whole.
  • Furna do Enxofre, a volcanic cavity with great interest of protection, preservation and sharing of biological, aesthetic, scientific. This structure is considered unique in the international volcano-speleological panorama and is a rare example of a cave and lake with small geysers assets, and its access via spiral staircase from the inside of a curious tower built inside the cave, forming the main tourist hallmark of Graciosa Island.
  • Capelinhos is one of the biggest tourist attractions of the Azores, the uniqueness of its landscape beauty of dark gray, very recent and almost virgin genesis, in a panel of browns and contrasting ferrous with the green of the surrounding countryside.
  • Pico Mountain presents a unique beauty as island, rising abruptly from the ocean floor from the mid-Atlantic ridge, especially when covered by winter snows in contrast to the black basalt mountain and green island foot, flanked by traditional vineyard, on the magnificent blue sea of the Azores.

Criterion (viii): exceptionally be representative examples of the great stages of earth's history, including testimonies of life, geological processes underway the development of landforms or of geomorphic or physiographic elements of great significance.

  • The hydrothermal fields are formed on hot spots in divergence areas of tectonic plates where new crust is formed, such as the Mid-Atlantic Ridge. These structures play an important role in regulating the temperature and chemical balance of the oceans and its study led to the development of new theories about the origin of life on earth.
  • The type of submarine volcanic eruption of 1957 that gave rise to the Capelinhos was the first reported. The capeliniana designation was not readily patented by Eng. Frederico Machado and during the Surtsey eruption in Iceland, in 1963, volcanologists quickly adopted the surtseyan terminology, when by law the designation would be capeliniana. The basaltic eruption that lasted for 13 months, began to be underwater and evolved into subaerial, an eruptive sequence also evident in the contiguous fossil cliffs of the "Costado da Nau." Its easy access allows all scientific monitoring of geological processes that have elapsed since its origin.
  • “Algar do Carvão” was classified as a "Regional Natural Monument" given its volcanological peculiarities. This is a remarkable volcanic chimney that contrary to what generally occurs in other cases is not completely blocked. The stalactites and stalagmites of white milky amorphous silica are considered the largest in the world.
  • The tip of Pico Mountain at 2351 m (38° 28'0" N, 28° 24'0" W) is itself the highest point of the Mid-Atlantic Ridge. If we considered the abyssal contiguous zone, the total elevation of the volcanic structure from the base reaches near 5000 meters, lying almost half submerged under the Atlantic waters.
  • “Furna do Enxofre” is one of the largest volcanic craters with a perfect and unique dome in the world, culminating in a fumarole of mud and a lake of cold water rich in sulfur. Formed within a subsidence caldera associated with explosive siliceous eruptions (the plinian type), that have originated about 12 000 years ago, its origin is associated with a major intracaldera effusive phase, Hawaiian type, wherein the existing lava within the caldera, still fluid, is drained along the main conduit of the volcano, the area where is the current cavity.

Criterion (ix): exceptionally be representative examples of ecological and biological cases in progress in the evolution and development of ecosystems and communities of plants and terrestrial animals, aquatic, coastal and marine ecosystems.

  • Hydrothermal fields have an abundance of wildlife supported by chemosynthetic organisms that rely on geothermal energy, a unique process on the planet. Home to one of the greatest microbial diversity known with high levels of production under extreme conditions of temperature and concentrations of heavy metals and toxic gases, hostile to life, which required peculiar adaptations of the fauna.
  • In Algar do Carvão are present numerous species of invertebrates, highlighting the development of endemic species restricted to the cave environment (troglobite).
  • In Furna do Enxofre is recorded the presence of bryophytes and vascular plants, invertebrates and troglobid fauna adapted to cavern ecosystem.
  • The Volcano of Pico Mountain, in ecological terms, home to the only alpine communities of the archipelago, especially for its uniqueness in terms of the context of the natural heritage of the Azores.
  • The recent genesis of Capelinhos allows observation of the ecological succession of phenomena of vegetation and its gradual colonization by the local fauna.

Criterion (x): contain the most representative natural habitats and important for in situ conservation of biological diversity, particularly those who endangered species survive that have an Outstanding Universal Value from the point of view of science or conservation.

In the continuum that extends from the abyssal depths and uneven topographic structures, hills and underwater aspects, through the short continental shelf and coastal areas to the inland habitats more plans and wooded coves, wetlands and large hillsides and mountains, which is part of the highest point of Portugal and Middle-Atlantic Ridge, are geological structures such as hydrothermal vents, caves, caverns and Algares, volcanoes and secondary manifestations of volcanism which are habitats that harbor great biodiversity, with plenty of endemic species, characteristic of the isolation of the islands in the center of the Atlantic, and various protection statutes at national and international level. Some species, such as those present in the vents, there are at current knowledge, anywhere else in the world.

Statements of authenticity and/or integrity

The Mid-Atlantic Ridge is an imposing geological manifestation. It is the longest range on the plant. Its development at the juncture of different tectonic plates stands out in this region, where the archipelago of the Azores is located. It is at this meeting point of three tectonic plates that the Platform of the Azores arises, where MAR is integrated.

This geological structure of triangular dimensions with roughly 400,000 km2 in area contains the islands of the archipelago, a significant part of the 10% of the length above sea level of MAR, and numerous seamounts.

The sinking of these seamounts occurs due to geological phenomena which continuously shape the geographical evolution and whose consequences are visible in the territories above sea level, having an impact on the everyday life and culture of Azorean populations.

The curiosity and respect for natural phenomena resulted in a religious way of life profoundly linked with geological phenomena, such as earthquakes and volcanoes, progressively complemented by an informed and pro-nature attitude. This attitude boosted early on the development of different protection instruments, specifically in the most impressive and beautiful sites. The making of the Island Natural Parks and the Marine Park of the Azores under the legislation in force in the Azores stands out. The different UNESCO classifications that this region holds and which fall upon the property demonstrate this and certify its integrity.

The representative areas that were selected demonstrate the richest and the most diverse conditions of this kind of geological manifestations in the geographical context in which the property is in and correspond to all the protected areas already classified under nature conservation diplomas, in order to ensure its coherence.

In addition to the described areas, the whole area of the archipelago is considered, in order to guarantee this way the standard of quality of the area for future classification.

The structures included in this property look to encompass all their manifestations and components. This is why the polygons selected to define the property are broad enough. The dimensions are considered sufficient to contain the necessary elements, which demonstrate key aspects of the processes that characterize the property.

Comparison with other similar properties

Regarding the defined area on this list, the Azores region has some characteristics that give uniqueness to clear exceptional value. There is no other place on the planet that contains the geographic and geological setting of the MAR of the Azores:

  • It has the highest elevation of all the Mid-Atlantic Ridge caused by the combination of a triple junction of divergent plates under which serves a hot spot, a situation comparable to the rare existing tectonic framework in the archipelago of the Galapagos Islands, which causes a thickening of the oceanic crust forming a plateau. However, in the Azores, the triple point is established between three of the seven large tectonic plates covering the ground (Nubian, Eurasian and American).
  • Two of the Azores Islands are located in the American Plate (Flores and Corvo), Santa Maria is in the Nubia plate (African) and the rest are on the three fractures that make up the rift of Terceira. Thus it can be said that the Azorean archipelago constitution is a testimony of processes that involve the MAR, even more so associated with a hotspot. These features make it unique and unmistakable valuable, since it is a unique location immersed and emerged volcanic activity, resulting in a total of 26 active volcanic systems, 8 of which submarines.
  • Pico Mountain has its top as the point of highest elevation of all the MAR, which ascends to 2351m above sea level.
  • Algar do Carvão has the world's largest silica stalactites and endemic invertebrate’s species.
  • The Furna do Enxofre is the largest volcanic dome in Europe and chimney of an active volcano, which interior can be visited.
  • The eruption of the Capelinhos was the subject of the first detailed scientific description of an eruption of surteseyan type, in this case, it was carried out from the lighthouse that was located opposite the site of the eruption, through notes, filming and photography, since its inception. The observation of this volcano was critical to understand the volcanological process in the MAR.
  • Although Iceland is the largest island in MAR (with 102 775 km2), the Azores represent an inhabited land area (population of approximately 240 000 inhabitants) extending over a much larger area of approximately 600 km in the NW-SE direction.
  • The Azores archipelago is the largest aggregation of islands associated with MAR.