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118-525: Human occupation on Berlenga Grande dates back to antiquity: the islands are referred to in Ptolemy's Geography as Λονδοβρίς ( Londobris ). Much later it was referred to as the island of Saturno by Roman geographers, and was visited successively by Muslims , Vikings and privateers . The islands are thought to be a former sacred place adopted by the Phoenicians in the first millennium BC where

236-532: A marine reserve . The water around the islands hosts a great variety of fish, at least 44 species are known from two study expeditions. The most frequently observed fish is the common two-banded sea bream and the ballan wrasse , along with the European bass , the red porgy , the gilt-head bream and the dusky grouper , frequent on Farilhões Islets. In the 1950s the islands were an important spawning ground for school sharks . The oceanographic conditions of

354-408: A distinctive composition or mode or origin. Special names still in wide use include amphibolite, greenschist , phyllite, marble, serpentinite , eclogite, migmatite , skarn , granulite , mylonite, and slate. The basic classification can be supplemented by terms describing mineral content or texture. For example, a metabasalt showing weak schistosity might be described as a gneissic metabasalt, and

472-455: A distinctive layering called foliation (derived from the Latin word folia , meaning "leaves"). Foliation develops when a rock is being shortened along one axis during recrystallization. This causes crystals of platy minerals, such as mica and chlorite , to become rotated such that their short axes are parallel to the direction of shortening. This results in a banded, or foliated, rock, with

590-455: A figure of 180,000 stadia for the circumference of the Earth, which he described as a "general consensus". Ptolemy rescaled experimentally obtained data in many of his works on geography, astrology, music, and optics. Metamorphic Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism . The original rock ( protolith )

708-585: A large part of the Earth's crust and form 12% of the Earth's land surface. They are classified by their protolith, their chemical and mineral makeup, and their texture . They may be formed simply by being deeply buried beneath the Earth's surface, where they are subject to high temperatures and the great pressure of the rock layers above. They can also form from tectonic processes such as continental collisions, which cause horizontal pressure, friction, and distortion. Metamorphic rock can be formed locally when rock

826-469: A marble will not be identical with the amphibolite facies of a pelite. However, the facies are defined such that metamorphic rock with as broad a range of compositions as is practical can be assigned to a particular facies. The present definition of metamorphic facies is largely based on the work of the Finnish geologist, Pentti Eskola , with refinements based on subsequent experimental work. Eskola drew upon

944-533: A metamorphic rock to be classified in this manner, the protolith should be identifiable from the characteristics of the metamorphic rock itself, and not inferred from other information. Under the British Geological Survey's classification system, if all that can be determined about the protolith is its general type, such as sedimentary or volcanic, the classification is based on the mineral mode (the volume percentages of different minerals in

1062-455: A number of notable caves, including Gruta Azul (English: "Blue Cave") and Furado Grande (English: "Big Hole"). The Furado Grande is a natural tunnel 70 metres (230 ft) wide and 20 metres (66 ft) tall which crosses through the entire island before opening up into a dramatic bay. The Fort of São João Baptista (English: "Fort of St. John the Baptist") is located in the waters off

1180-506: A number of tourists. There is little soil on the rocky archipelago, so little plant life is supported. Sea birds and marine life, such as mackerel , mullet , and swordfish are abundant. At 1.5 kilometres (0.9 mi) long and 0.8 kilometres (0.50 mi) wide, Berlenga Grande is the largest of the islands of the Berlengas Archipelago. At its highest, it rises to 88 metres (289 ft) above sea level . The island has

1298-413: A pelite containing abundant staurolite might be described as a staurolite pelite. [REDACTED] A metamorphic facies is a set of distinctive assemblages of minerals that are found in metamorphic rock that formed under a specific combination of pressure and temperature. The particular assemblage is somewhat dependent on the composition of that protolith, so that (for example) the amphibolite facies of

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1416-576: A quarter of the globe. Ptolemy's work included a single large and less detailed world map and then separate and more detailed regional maps. The first Greek manuscripts compiled after Maximus Planudes 's rediscovery of the text had as many as 64 regional maps. The standard set in Western Europe came to be 26: 10 European maps, 4 African maps, and 12 Asian maps. As early as the 1420s, these canonical maps were complemented by extra-Ptolemaic regional maps depicting, e.g., Scandinavia . An outline of

1534-519: A relatively mild grade of metamorphism, at temperatures of 350–500 °C (662–932 °F) and pressures of 200–500 MPa (2,000–5,000 bar). They can be divided into a lower group of metabasalts, including rare meta komatiites ; a middle group of meta-intermediate-rock and meta-felsic-rock; and an upper group of metasedimentary rock. The greenstone belts are surrounded by high-grade gneiss terrains showing highly deformed low-pressure, high-temperature (over 500 °C (932 °F)) metamorphism to

1652-688: A scribal error was made and Cattigara was located at eight and a half degrees South of the Equator. On Ptolemaic maps, such as that of Martellus, Catigara was located on the easternmost shore of the Mare Indicum, 180 degrees East of the Cape St Vincent at, due to the scribal error, eight and a half degrees South of the Equator. Catigara is also shown at this location on Martin Waldseemüller's 1507 world map, which avowedly followed

1770-551: A statement on 30 June 2011, the list of classified reserves were presented. The archipelago is made up of the largest island, Berlenga Grande, and two groups of smaller islets, the Estelas Inlets and the Farilhões-Forcados Islets. As the archipelago has been declared a reservation area for the protection of the local fauna (primarily sea birds), it is only visited by scientists and, in the summer, by

1888-410: A variety of metamorphic facies. Where subduction is taking place, the basalt of the subducting slab is metamorphosed to high-pressure metamorphic facies. It initially undergoes low-grade metamorphism to metabasalt of the zeolite and prehnite-pumpellyite facies , but as the basalt subducts to greater depths, it is metamorphosed to the blueschist facies and then the eclogite facies . Metamorphism to

2006-417: Is a great variety of metamorphic rock types. In general, if the protolith of a metamorphic rock can be determined, the rock is described by adding the prefix meta- to the protolith rock name. For example, if the protolith is known to be basalt , the rock will be described as a metabasalt. Likewise, a metamorphic rock whose protolith is known to be a conglomerate will be described as a metaconglomerate . For

2124-399: Is a treatise on cartography and chorography , describing the methods used to assemble and arrange Ptolemy's data. From Book II through the beginning of Book VII, a gazetteer provides longitude and latitude values for the world known to the ancient Romans (the " ecumene "). The rest of Book VII provides details on three projections to be used for the construction of a map of

2242-530: Is also prized for building construction and as a medium for sculpture. On the other hand, schist bedrock can pose a challenge for civil engineering because of its pronounced planes of weakness. Metamorphic rocks form one of the three great divisions of rock types. They are distinguished from igneous rocks , which form from molten magma , and sedimentary rocks , which form from sediments eroded from existing rock or precipitated chemically from bodies of water. Metamorphic rocks are formed when existing rock

2360-426: Is called a paired metamorphic belt . The main islands of Japan show three distinct paired metamorphic belts, corresponding to different episodes of subduction. Metamorphic rock is also exposed in metamorphic core complexes , which form in region of crustal extension. They are characterized by low-angle faulting that exposes domes of middle or lower crust metamorphic rock. These were first recognized and studied in

2478-464: Is dominated by metamorphic rock that has reached the amphibolite facies. Within the upper crust, which is the only part of the Earth's crust geologists can directly sample, metamorphic rock forms only from processes that can occur at shallow depth. These are contact (thermal) metamorphism , dynamic (cataclastic) metamorphism , hydrothermal metamorphism , and impact metamorphism . These processes are relatively local in occurrence and usually reach only

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2596-476: Is formed as tectonic plates move apart. Hydrothermal metamorphism is extensive here. This is characterized by metasomatism by hot fluids circulating through the rock. This produces metamorphic rock of the greenschist facies. The metamorphic rock, serpentinite , is particularly characteristic of these settings, and represents chemical transformation of olivine and pyroxene in ultramafic rock to serpentine group minerals. Contact metamorphism takes place when magma

2714-464: Is heated by the intrusion of hot molten rock called magma from the Earth's interior. The study of metamorphic rocks (now exposed at the Earth's surface following erosion and uplift) provides information about the temperatures and pressures that occur at great depths within the Earth's crust. Some examples of metamorphic rocks are gneiss , slate , marble , schist , and quartzite . Slate and quartzite tiles are used in building construction. Marble

2832-403: Is injected into the surrounding solid rock ( country rock ). The changes that occur are greatest wherever the magma comes into contact with the rock because the temperatures are highest at this boundary and decrease with distance from it. Around the igneous rock that forms from the cooling magma is a metamorphosed zone called a contact aureole . Aureoles may show all degrees of metamorphism from

2950-405: Is known as burial metamorphism . This tends to produce low-grade metamorphic rock. Much more common is metamorphic rock formed during the collision process itself. The collision of plates causes high temperatures, pressures and deformation in the rocks along these belts. Metamorphic rock formed in these settings tends to shown well-developed schistosity. Metamorphic rock of orogenic belts shows

3068-451: Is subjected to temperatures greater than 150 to 200 °C (300 to 400 °F) and, often, elevated pressure of 100 megapascals (1,000  bar ) or more, causing profound physical or chemical changes. During this process, the rock remains mostly in the solid state, but gradually recrystallizes to a new texture or mineral composition. The protolith may be an igneous , sedimentary , or existing metamorphic rock. Metamorphic rocks make up

3186-506: Is sufficiently hard and dense that it is difficult to quarry. However, some quartzite is used as dimension stone , often as slabs for flooring, walls, or stairsteps. About 6% of crushed stone, used mostly for road aggregate, is quartzite. Marble is also prized for building construction and as a medium for sculpture. Schistose bedrock can pose a challenge for civil engineering because of its pronounced planes of weakness. A hazard may exist even in undisturbed terrain. On August 17, 1959,

3304-553: Is transformed physically or chemically at elevated temperature, without actually melting to any great degree. The importance of heating in the formation of metamorphic rock was first noted by the pioneering Scottish naturalist, James Hutton , who is often described as the father of modern geology. Hutton wrote in 1795 that some rock beds of the Scottish Highlands had originally been sedimentary rock but had been transformed by great heat. Hutton also speculated that pressure

3422-400: Is uncertain. Special classifications exist for metamorphic rocks with a volcaniclastic protolith or formed along a fault or through hydrothermal circulation . A few special names are used for rocks of unknown protolith but known modal composition, such as marble, eclogite , or amphibolite . Special names may also be applied more generally to rocks dominated by a single mineral, or with

3540-648: Is used now, though Ptolemy used fractions of a degree rather than minutes of arc. His Prime Meridian , of 0 longitude , ran through the Fortunate Isles , the westernmost land recorded, at around the position of El Hierro in the Canary Islands . The maps spanned 180 degrees of longitude from the Fortunate Isles in the Atlantic to China . Ptolemy was aware that Europe knew only about

3658-426: Is used only when very little else is known about the rock that would allow a more definite classification. Textural classifications may be prefixed to indicate a sedimentary protolith ( para- , such as paraschist) or igneous protolith ( ortho- , such as orthogneiss). When nothing is known about the protolith, the textural name is used without a prefix. For example, a schist is a rock with schistose texture whose protolith

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3776-475: Is usually devoid of schistosity and forms a tough, equigranular rock. If the rock was originally banded or foliated (as, for example, a laminated sandstone or a foliated calc- schist ) this character may not be obliterated, and a banded hornfels is the product. Contact metamorphism close to the surface produces distinctive low-pressure metamorphic minerals, such as spinel , andalusite, vesuvianite , or wollastonite . Similar changes may be induced in shales by

3894-470: Is very low in silica) to metafelsic-rock (with a high silica content). Where the mineral mode cannot be determined, as is often the case when rock is first examined in the field , then classification must be based on texture. The textural types are: A hornfels is a granofels that is known to result from contact metamorphism. A slate is a fine-grained metamorphic rock that easily splits into thin plates but shows no obvious compositional layering. The term

4012-648: The Geographia and the Cosmographia , is a gazetteer , an atlas , and a treatise on cartography , compiling the geographical knowledge of the 2nd-century Roman Empire . Originally written by Claudius Ptolemy in Greek at Alexandria around 150 AD, the work was a revision of a now-lost atlas by Marinus of Tyre using additional Roman and Persian gazetteers and new principles. Its translation – Kitab Surat al-Ard – into Arabic by Al-Khwarismi in

4130-585: The Azores High and gives rise to a wind regime known as the Nortada . These winds push surface waters offshore, causing cold waters from deeper layers of the water to replace warm surface waters in an upwelling process. This phenomenon causes frequent mists during summer and results in nutrient enrichment of surface water. Average monthly temperatures in summer are cool (below 20 °C (68 °F)) and highs rarely exceed 25 °C (77 °F). In winter,

4248-570: The Basin and Range Province of southwestern North America, but are also found in southern Aegean Sea , in the D'Entrecasteaux Islands , and in other areas of extension. Continental shields are regions of exposed ancient rock that make up the stable cores of continents. The rock exposed in the oldest regions of shields, which is of Archean age (over 2500 million years old), mostly belong to granite-greenstone belts. The greenstone belts contain metavolcanic and metasedimentary rock that has undergone

4366-488: The Canary Islands . He said that he had sailed 1100 leagues from the Canaries when he found Cuba in 1492. This was approximately where he thought the coast of eastern Asia would be found. On this basis of calculation he identified Hispaniola with Cipangu, which he had expected to find on the outward voyage at a distance of about 700 leagues from the Canaries. His later voyages resulted in further exploration of Cuba and in

4484-705: The Geography in providing the coordinates for 545 cities and regional maps of the Nile , the Island of the Jewel , the Sea of Darkness, and the Sea of Azov . A 1037 copy of these are the earliest extant maps from Islamic lands. The text clearly states that al-Khwārazmī was working from an earlier map, although this could not have been an exact copy of Ptolemy's work: his Prime Meridian

4602-732: The Magnus Sinus . This known portion of the world was comprised within 180 degrees. In his extreme east Ptolemy placed Serica (the Land of Silk), the Sinarum Situs (the Port of the Sinae ), and the emporium of Cattigara . On the 1489 map of the world by Henricus Martellus, which was based on Ptolemy's work, Asia terminated in its southeastern point in a cape, the Cape of Cattigara. Cattigara

4720-633: The Marvels of the Seven Climes to the End of Habitation . Surviving maps from the medieval period were not done according to mathematical principles. The world map from the 11th-century Book of Curiosities is the earliest surviving map of the Muslim or Christian worlds to include a geographic coordinate system but the copyist seems to have not understood its purpose, starting it from the left using twice

4838-450: The atoms and ions in solid crystals to migrate, thus reorganizing the crystals, while high pressures cause solution of the crystals within the rock at their point of contact. Metamorphic rocks are characterized by their distinctive mineral composition and texture. Because every mineral is stable only within certain limits, the presence of certain minerals in metamorphic rocks indicates the approximate temperatures and pressures at which

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4956-476: The black redstart and the peregrine falcon . It is also in the southernmost range of the common murre (adopted as the symbol of the nature reserve) and is one of the few breeding locations of the band-rumped storm petrel . A new endemic species of snail, Oestophora barrelsi spec. nov was described in 2015. The Berlengas archipelago is situated off of Peniche, south of the Nazaré Canyon and on

5074-402: The crystallization of igneous rocks. They are stable at high temperatures and pressures and may remain chemically unchanged during the metamorphic process. Metamorphic rocks are typically more coarsely crystalline than the protolith from which they formed. Atoms in the interior of a crystal are surrounded by a stable arrangement of neighboring atoms. This is partially missing at the surface of

5192-470: The "sugar loaf", or even narrow valleys with almost vertical walls (the carreiros , formed by selective erosion along subvertical fault planes), as well as numerous caves and marine tunnels The different groups of islands have different morphology, composition and origins. Berlenga Grande and Estelas are of igneous origin, composed of pink granites , and occur in outcrops with rounded morphologies, generally with flattened tops. The Farilhões Forcadas group, on

5310-483: The 12th century AD. However, no copy of that translation has survived. The Greek text of the Geography reached Florence from Constantinople in about 1400 and was translated into Latin by Jacobus Angelus of Scarperia around 1406. The first printed edition with maps, published in 1477 in Bologna , was also the first printed book with engraved illustrations. Many editions followed (more often using woodcut in

5428-403: The 3rd century BC. Ptolemy improved the treatment of map projections . He provided instructions on how to create his maps in the first section of the work. The gazetteer section of Ptolemy's work provided latitude and longitude coordinates for all the places and geographical features in the work. Latitude was expressed in degrees of arc from the equator , the same system that

5546-515: The 9th century was highly influential on the geographical knowledge and cartographic traditions of the Islamic world . Alongside the works of Islamic scholars – and the commentary containing revised and more accurate data by Alfraganus – Ptolemy's work was subsequently highly influential on Medieval and Renaissance Europe. Versions of Ptolemy's work in antiquity were probably proper atlases with attached maps, although some scholars believe that

5664-493: The Atlantic, especially on the northern and northwestern coasts, where strong winds are felt. Heavy rains in winter alternate with periods of drought, between spring and autumn. The climate of the archipelago is strongly influenced by the winds, very strong on the north-facing cliffs and more moderate on the southern coasts. These wind currents affect the distribution of flora and fauna in the islands. This climatic feature endows

5782-514: The Berlengas throughout documented history. In 1808, HMS  Milbrook wrecked on Berlenga Grande in a gale, though without loss of life. Berlenga Grande did star in a post-revolutionary Portuguese film called O Rei das Berlengas (The King of the Berlengas), a comedy about someone who decides to become king of the archipelago. In this movie, several people, tourists and residents from

5900-563: The Elder demonstrated a reluctance to rely on the contemporary accounts of sailors and merchants who plied distant areas of the Indian Ocean , Marinus and Ptolemy betray a much greater receptiveness to incorporating information received from them. For instance, Grant Parker argues that it would be highly implausible for them to have constructed the Bay of Bengal as precisely as they did without

6018-465: The Papoa tuff – breccia , similar to those recognized in the archipelago, confirms this hypothesis. It is also expected that this block was larger and had a different configuration than it currently has. The absence of morphological structures typical of the erosion of granitic massifs and soils on the surface of Berlenga Grande suggest that it was underwater for long periods of time. Its rounded shape and

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6136-400: The above stemma descends, even if maps existed in antiquity: "The transmission of Ptolemy's text certainly passed through a stage when the manuscripts were too small to contain the maps. Planudes and his assistants therefore probably had no pictorial models, and the success of their enterprise is proof that Ptolemy succeeded in his attempt to encode the map in words and numbers. The copies of

6254-553: The accounts of sailors. When it comes to the account of the Golden Chersonese (i.e. Malay Peninsula ) and the Magnus Sinus (i.e. Gulf of Thailand and South China Sea ), Marinus and Ptolemy relied on the testimony of a Greek sailor named Alexandros, who claimed to have visited a far eastern site called " Cattigara " (most likely Oc Eo , Vietnam , the site of unearthed Antonine -era Roman goods and not far from

6372-482: The amphibolite or granulite facies. These form most of the exposed rock in Archean cratons. The granite-greenstone belts are intruded by a distinctive group of granitic rocks called the tonalite - trondhjemite - granodiorite or TTG suite. These are the most voluminous rocks in the craton and may represent an important early phase in the formation of continental crust. Mid-ocean ridges are where new oceanic crust

6490-456: The archipelago commonly lead to an abundant ichthyofauna , represented by sardines and other species that feed on plankton. This attracts a lot of marine mammals, mainly cetaceans , whose species include the common dolphin , the common bottlenose dolphin , the harbour porpoise , the striped dolphin , the common minke whale and the Cuvier's beaked whale . A number of ships have wrecked on

6608-419: The archipelago with a unique ecosystem, both on land and at sea level. The presence close to the mainland, whose coast is oriented north–south, also strongly influences the climatic characteristics of the island, especially in summer. In this season, the differential warming of the sea and the land causes the formation of a sea breeze during the day. This breeze strengthens the main wind current associated with

6726-466: The archipelago. Human presence led to the introduction of exotic species, like the ice plant and small mammals like the European rabbit and the black rat who work to diminish the native population. There are two species of lizard in the islands, the Carbonell's wall lizard (subs. berlengensis) and the ocellated lizard , although this last one is residual and is only seen in restricted areas of

6844-404: The bands showing the colors of the minerals that formed them. Foliated rock often develops planes of cleavage . Slate is an example of a foliated metamorphic rock, originating from shale , and it typically shows well-developed cleavage that allows slate to be split into thin plates. The type of foliation that develops depends on the metamorphic grade. For instance, starting with a mudstone ,

6962-568: The basis of his (now lost) Chorography of the Ecumene . Later imperial writers and mathematicians, however, seem to have restricted themselves to commenting on Ptolemy's text, rather than improving upon it; surviving records actually show decreasing fidelity to real position. Nevertheless, Byzantine scholars continued these geographical traditions throughout the Medieval period. Whereas previous Greco-Roman geographers such as Strabo and Pliny

7080-420: The bulk composition of a rock. Hot fluids circulating through pore space in the rock can dissolve existing minerals and precipitate new minerals. Dissolved substances are transported out of the rock by the fluids while new substances are brought in by fresh fluids. This can obviously change the mineral makeup of the rock. However, changes in the mineral composition can take place even when the bulk composition of

7198-399: The burning of coal seams. This produces a rock type named clinker . There is also a tendency for metasomatism between the igneous magma and sedimentary country rock, whereby the chemicals in each are exchanged or introduced into the other. In that case, hybrid rocks called skarn arise. Dynamic (cataclastic) metamorphism takes place locally along faults . Here intense shearing of

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7316-435: The circulation of fluids through buried rock, to the list of processes that help bring about metamorphism. However, metamorphism can take place without metasomatism ( isochemical metamorphism ) or at depths of just a few hundred meters where pressures are relatively low (for example, in contact metamorphism ). Metamorphic processes change the texture or mineral composition of the metamorphosed rock. Metasomatism can change

7434-427: The collision of tectonic plates at convergent boundaries . Here formerly deeply buried rock has been brought to the surface by uplift and erosion. The metamorphic rock exposed in orogenic belts may have been metamorphosed simply by being at great depths below the Earth's surface, subjected to high temperatures and the great pressure caused by the immense weight of the rock layers above. This kind of regional metamorphism

7552-491: The contact area to unmetamorphosed (unchanged) country rock some distance away. The formation of important ore minerals may occur by the process of metasomatism at or near the contact zone. Contact aureoles around large plutons may be as much as several kilometers wide. The term hornfels is often used by geologists to signify those fine grained, compact, non-foliated products of contact metamorphism. The contact aureole typically shows little deformation, and so hornfels

7670-503: The coordinates provided by the text, as Planudes was forced to do. Later scribes and publishers could then copy these new maps, as Athanasius did for the emperor Andronicus II Palaeologus . The three earliest surviving texts with maps are those from Constantinople ( Istanbul ) based on Planudes's work. The first Latin translation of these texts was made in 1406 or 1407 by Jacobus Angelus in Florence , Italy , under

7788-612: The crystal, producing a surface energy that makes the surface thermodynamically unstable. Recrystallization to coarser crystals reduces the surface area and so minimizes the surface energy. Although grain coarsening is a common result of metamorphism, rock that is intensely deformed may eliminate strain energy by recrystallizing as a fine-grained rock called mylonite . Certain kinds of rock, such as those rich in quartz, carbonate minerals , or olivine, are particularly prone to form mylonites, while feldspar and garnet are resistant to mylonitization. Many kinds of metamorphic rocks show

7906-623: The cult of Baal – Melqart was celebrated. In 1513, with the support of Queen Eleanor of Viseu , monks from the Order of São Jerónimo established a settlement on the island to offer assistance to navigation and victims of frequent shipwrecks. The monastery founded there, the Monastery of the Misericórdia da Berlenga, remained until the 16th century, when disease, lack of supplies and poor communication (due to constant inclement weather) forced

8024-460: The discovery of South and Central America . At first South America, the Mundus Novus ( New World ) was considered to be a great island of continental proportions; but as a result of his fourth voyage , it was apparently considered to be identical with the great Upper India peninsula ( India Superior ) represented by Behaim – the Cape of Cattigara. This seems to be the best interpretation of

8142-520: The early days), some following traditional versions of the maps, and others updating them. An edition printed at Ulm in 1482 was the first one printed north of the Alps . Also in 1482, Francesco Berlinghieri printed the first edition in vernacular Italian . Ptolemy had mapped the whole world from the Fortunatae Insulae ( Cape Verde or Canary Islands ) eastward to the eastern shore of

8260-423: The eclogite facies releases a great deal of water vapor from the rock, which drives volcanism in the overlying volcanic arc . Eclogite is also significantly denser than blueschist, which drives further subduction of the slab deep into the Earth's mantle . Metabasalt and blueschist may be preserved in blueschist metamorphic belts formed by collisions between continents. They may also be preserved by obduction onto

8378-539: The edge of the continental shelf (in Farilhões Islets) on a maritime zone known by its relatively high biological productivity , acting as a meeting point between coastal and oceanic fish species. On the other hand, the upwelling currents originating in deep waters contribute to the development of an aquatic fauna with evident commercial interest. Its variety of fish and marine mammals, marine plants and other marine organisms as led to its classification as

8496-474: The encyclopedia follows, with links to the appropriate Misplaced Pages article. The original treatise by Marinus of Tyre that formed the basis of Ptolemy's Geography has been completely lost. A world map based on Ptolemy was displayed in Augustodunum ( Autun , France ) in late Roman times. Pappus , writing at Alexandria in the 4th century, produced a commentary on Ptolemy's Geography and used it as

8614-479: The end of the thirteenth century, which are the earliest extant manuscripts of the Geography; these are U, K & F. Recension, Ξ, is represented by one codex only, X. Mittenhuber agrees with Berggren & Jones, stating that "The so-called Codex X is of particular significance, because it contains many local names and coordinates that differ from the other manuscripts ... which cannot be explained by mere errors in

8732-663: The extensive additions to the Ptolemaic map shown on the 1492 globe of Martin Behaim . The fact that Ptolemy did not represent an eastern coast of Asia made it admissible for Behaim to extend that continent far to the east. Behaim’s globe placed Marco Polo’s Mangi and Cathay east of Ptolemy’s 180th meridian, and the Great Khan’s capital, Cambaluc ( Beijing ), on the 41st parallel of latitude at approximately 233 degrees East. Behaim allowed 60 degrees beyond Ptolemy’s 180 degrees for

8850-437: The following sequence develops with increasing temperature: The mudstone is first converted to slate, which is a very fine-grained, foliated metamorphic rock, characteristic of very low grade metamorphism. Slate in turn is converted to phyllite , which is fine-grained and found in areas of low grade metamorphism. Schist is medium to coarse-grained and found in areas of medium grade metamorphism. High-grade metamorphism transforms

8968-449: The identical composition, Al 2 SiO 5 . Likewise, forsterite is stable over a broad range of pressure and temperature in marble , but is converted to pyroxene at elevated pressure and temperature in more silicate-rich rock containing plagioclase , with which the forsterite reacts chemically. Many complex high-temperature reactions may take place between minerals without them melting, and each mineral assemblage produced indicates

9086-409: The intended scale and then (apparently realizing his mistake) giving up halfway through. Its presence does strongly suggest the existence of earlier, now-lost maps which had been mathematically derived in the manner of Ptolemy, al-Khwārazmi, or Suhrāb. There are surviving reports of such maps. Ptolemy's Geography was translated from Arabic into Latin at the court of King Roger II of Sicily in

9204-596: The island of Berlenga into two fragments, the Ilha Velha and the Berlenga itself, and give it a curious figure-eight shape. It is hypothesized that the archipelago had its origin on a horst . Its absence on the Mesozoic suggests that, during this time, the Berlengas block was essentially subjected to erosive processes. The pink granite fragments and metamorphic rocks found at Cabo Carvoeiro or Baleal, as well as in

9322-419: The islands such as caves and is thought to be different from the continental relatives, showing different morphological traits and demeanor . The Berlengas archipelago is an important breeding area for seabirds such as the lesser black-backed gull and the yellow-legged gull , whose population increased dramatically due to artificial feeding and has become a serious problem in some cases, and land birds like

9440-467: The length of a degree instead of the longer degree of Ptolemy, and by adopting Marinus of Tyre ’s longitude of 225 degrees for the east coast of the Magnus Sinus . This resulted in a considerable eastward advancement of the longitudes given by Martin Behaim and other contemporaries of Columbus. By some process Columbus reasoned that the longitudes of eastern Asia and Cipangu respectively were about 270 and 300 degrees east, or 90 and 60 degrees west of

9558-437: The low-pressure facies, such as the hornfels and sanidinite facies . Most metamorphic rock is formed by regional metamorphism in the middle and lower crust, where the rock reaches the higher-pressure metamorphic facies. This rock is found at the surface only where extensive uplift and erosion has exhumed rock that was formerly much deeper in the crust. Metamorphic rock is extensively exposed in orogenic belts produced by

9676-613: The mainland of Asia and 30 degrees more to the east coast of Cipangu (Japan). Cipangu and the mainland of Asia were thus placed only 90 and 120 degrees, respectively, west of the Canary Islands. The Codex Seragliensis was used as the base of a new edition of the work in 2006. This new edition was used to "decode" Ptolemy's coordinates of Books 2 and 3 by an interdisciplinary team of TU Berlin , presented in publications in 2010 and 2012. Christopher Columbus modified this geography further by using 53⅔ Italian nautical miles as

9794-413: The maps in later manuscripts and printed editions of the Geography were reproduced from Planudes' reconstructions." Mittenhuber (2010) further divides the stemma into two recensions of the original c.AD 150 lost work: Ξ and Ω (c.3rd/4th cent., lost). Recension Ω contains most of the extant manuscripts and is subdivided into a further two groups: Δ and Π . Group Δ contains parchment manuscripts from

9912-487: The maps were either copied defectively for not at all. "Of the greatest importance for the text of the Geography" they state is manuscript X ( Vat.Gr.191 ); "because it is the only copy that is uninfluenced by the Byzantine revision." e.g. the 13th-14th century corrections of Planudes, possibly associated with recreating the maps. Regarding the maps, they conclude that it was unlikely that extant maps survived from which

10030-701: The monks to abandon their service on the island. After the Portuguese Restoration War , during the reign of King John IV , the council of war determined that the demolition of the monastery ruins and the use of their rocks to build a coastal defense would help protect the coastal settlements; the Fort of São João Baptista das Berlengas was constructed from the remnants of the monastery ruins. By 1655, it had already, during its construction, resisted an assault by three Barbary Coast pirates. The island's lighthouse (dubbed Duke of Braganza by locals)

10148-419: The monthly averages remain high (above 12 °C (54 °F)) and the minimum above 10 °C (50 °F). The thermal amplitude (both diurnal temperature variation and yearly temperature variation) therefore remains moderate. Due to generally cloudy conditions in the winter and the summer morning fog, the archipelago has a relatively low number of sunshine hours, though clear sky afternoons are frequent in

10266-488: The name Geographia Claudii Ptolemaei . It is not thought that his edition had maps, although Manuel Chrysoloras had given Palla Strozzi a Greek copy of Planudes's maps in Florence in 1397. Berggren & Jones (2000) place these manuscripts into a stemma whereby U, K, F and N are connected with the activities of Maximos Planudes (c.1255-1305). From a sister manuscript to UKFN descends R, V, W & C, however

10384-432: The nearby towns, attempt to declare the independence of the islands, and declare themselves as king, prince or president of the Berlengas. These declarations and liberation armies are nothing more than fiction intended for amusement. Geography (Ptolemy) The Geography ( Ancient Greek : Γεωγραφικὴ Ὑφήγησις , Geōgraphikḕ Hyphḗgēsis , lit.  "Geographical Guidance"), also known by its Latin names as

10502-508: The other hand, consists of metamorphic rocks, where reliefs characterized by sharp peaks and vertical cliffs stand out. Berlenga Island is a pink granite plateau with rounded shapes, marked by a very jagged coastline, where several coves, caves, arches, paths, small islets and rocks stand out. All these landforms were shaped by the continuous action of erosive processes over a long period of time. The very embedded and relatively aligned paths of Cações and Mosteiro stand out, which almost separate

10620-460: The overriding plate as part of ophiolites . Eclogites are occasionally found at sites of continental collision, where the subducted rock is rapidly brought back to the surface, before it can be converted to the granulite facies in the hot upper mantle. Many samples of eclogite are xenoliths brought to the surface by volcanic activity. Many orogenic belts contain higher-temperature, lower-pressure metamorphic belts. These may form through heating of

10738-414: The references to maps in the text were later additions. No Greek manuscript of the Geography survives from earlier than the 13th century. A letter written by the Byzantine monk Maximus Planudes records that he searched for one for Chora Monastery in the summer of 1295; one of the earliest surviving texts may have been one of those he then assembled. In Europe, maps were sometimes redrawn using

10856-479: The region of Jiaozhi in northern Vietnam where ancient Chinese sources claim several Roman embassies first landed in the 2nd and 3rd centuries). Muslim cartographers were using copies of Ptolemy's Almagest and Geography by the 9th century. At that time, in the court of the caliph al-Maʾmūm , al-Khwārazmī compiled his Book of the Depiction of the Earth ( Kitab Surat al-Ard ) which mimicked

10974-529: The relatively flat surface of its top propounds the presence of an ancient marine abrasion platform, confirmed by the presence of numerous erosive forms, such as potholes , which developed on top of the applanation surface when it was at the bottom of the sea. On the other hand, the existence of small cavities and caves in the cliffs above the current mean sea level, such as Furado Seco, and marine terraces that correspond to residual deposits of old beaches, located at similar altitudes, seem to indicate that sea level

11092-475: The rock by ascending magmas of volcanic arcs, but on a regional scale. Deformation and crustal thickening in an orogenic belt may also produce these kinds of metamorphic rocks. These rocks reach the greenschist , amphibolite, or granulite facies and are the most common of metamorphic rocks produced by regional metamorphosis. The association of an outer high-pressure, low-temperature metamorphic zone with an inner zone of low-pressure, high-temperature metamorphic rocks

11210-421: The rock does not change. This is possible because all minerals are stable only within certain limits of temperature, pressure, and chemical environment. For example, at atmospheric pressure, the mineral kyanite transforms to andalusite at a temperature of about 190 °C (374 °F). Andalusite, in turn, transforms to sillimanite when the temperature reaches about 800 °C (1,470 °F). All three have

11328-423: The rock to gneiss , which is coarse to very coarse-grained. Rocks that were subjected to uniform pressure from all sides, or those that lack minerals with distinctive growth habits, will not be foliated. Marble lacks platy minerals and is generally not foliated, which allows its use as a material for sculpture and architecture. Metamorphic rocks are one of the three great divisions of all rock types, and so there

11446-495: The rock typically forms mylonites. Impact metamorphism is unlike other forms of metamorphism in that it takes place during impact events by extraterrestrial bodies. It produces rare ultrahigh pressure metamorphic minerals, such as coesite and stishovite . Coesite is rarely found in eclogite brought to the surface in kimberlite pipes , but the presence of stishovite is unique to impact structures. Slate tiles are used in construction, particularly as roof shingle. Quartzite

11564-407: The rock underwent metamorphism. These minerals are known as index minerals . Examples include sillimanite , kyanite , staurolite , andalusite , and some garnet . Other minerals, such as olivines , pyroxenes , hornblende , micas , feldspars , and quartz , may be found in metamorphic rocks but are not necessarily the result of the process of metamorphism. These minerals can also form during

11682-486: The rock). Metasedimentary rocks are divided into carbonate-rich rock (metacarbonates or calcsilicate-rocks) or carbonate-poor rocks, and the latter are further classified by the relative abundance of mica in their composition. This ranges from low-mica psammite through semipelite to high-mica pelite . Psammites composed mostly of quartz are classified as quartzite. Metaigneous rocks are classified similarly to igneous rocks, by silica content, from meta-ultramafic-rock (which

11800-406: The sedimentary rock limestone and chalk change into larger crystals in the metamorphic rock marble . In metamorphosed sandstone, recrystallization of the original quartz sand grains results in very compact quartzite, also known as metaquartzite, in which the often larger quartz crystals are interlocked. Both high temperatures and pressures contribute to recrystallization. High temperatures allow

11918-403: The sketch map made by Alessandro Zorzi on the advice of Bartholomew Columbus (Christopher's brother) around 1506, which bears an inscription saying that according to the ancient geographer Marinus of Tyre and Christopher Columbus the distance from Cape St Vincent on the coast of Portugal to Cattigara on the peninsula of India Superior was 225 degrees, while according to Ptolemy the same distance

12036-592: The southeastern coast of Berlenga Grande, on a small islet connected to the island by a causeway/arch-bridge and anchorage to the north. It has been retrofitted as a rest house for tourists to stay at while visiting the islands. The Farilhões-Forcados Islets are uninhabited islands located northwest of Berlenga Grande. These islands consist of a pink granite very rare in Europe and very common in America, rich in feldspars . Erosion has created remarkable landforms, such as

12154-510: The speed of variations in the mean sea level. The older metamorphic rocks that outcrop in Farilhões and Forcadas are erosion-resistance peaks of an underwater mountain that widens considerably below sea level. These rocks are strongly deformed and contain textures and minerals characteristic of high pressure and high temperature environments, typical of the lower crust. The Berlengas have a Mediterranean climate ( Köppen : Csb ) dominated by

12272-615: The summer. Averages for the closest point on the mainland to the islands, Cabo Carvoeiro, are expressed in the climate box below: The flora of the Berlengas mainly consists of bushes and grasses, adapted to the strong winds, high aridity and salinity, some of them are common on the coastal mainland , others are endemic to the islands. There are two known endemic species to the islands, Armeria berlengensis and Pulicaria microcephala ; and two subspecies, Echium rosulatum subsp. davaei and Herniaria lusitanica subsp. berlengiana . There are around 100 different plant species present on

12390-446: The surviving manuscript tradition can be seen in the epitomes of Markianos by Stephanus : "Καὶ ἄλλοι οὕτως διὰ του π Πρετανίδες νῆσοι, ὡς Μαρκιανὸς καὶ Πτολεμαῖος ." The tradition preserved within the stemma of surviving (13th-14th century) manuscripts by Stückelberger & Grasshoff only preserves " Β " and not " Π " recentions of " Βρεττανικήσ ". The Geography consists of three sections, divided among 8 books. Book I

12508-404: The temperatures and pressures at the time of metamorphism. These reactions are possible because of rapid diffusion of atoms at elevated temperature. Pore fluid between mineral grains can be an important medium through which atoms are exchanged. The change in the particle size of the rock during the process of metamorphism is called recrystallization . For instance, the small calcite crystals in

12626-559: The tradition of Ptolemy. Ptolemy's information was thereby misinterpreted so that the coast of China, which should have been represented as part of the coast of eastern Asia, was falsely made to represent an eastern shore of the Indian Ocean. As a result, Ptolemy implied more land east of the 180th meridian and an ocean beyond. Marco Polo ’s account of his travels in eastern Asia described lands and seaports on an eastern ocean apparently unknown to Ptolemy. Marco Polo’s narrative authorized

12744-629: The tradition.". Although no manuscripts survive from earlier than the late 13th century; there are references to the existence of ancient codicies in late antiquity. One such example is in an epistle by Cassiodorus (c.560 A.D.): “Tum, si vos notitiae nobilis cura inflammaverit, habetis Ptolemaei codicem, qui sic omnia loca evidenter expressit, ut eum cunctarum regionum paene incolam fuisse iudicetis. Eoque fit, ut uno loco positi, sicut monachos decet, animo percurratis, quod aliquorum peregrinatio plurimo labore collegit.”( Institutiones 1, 25) . The existence of ancient recensions that differ fundamentally to

12862-451: The use of granulite as a classification for rock metamorphosed to the granulite facies. Instead, such rock will often be classified as a granofels. However, this approach is not universally accepted. Metamorphic rocks make up a large part of the Earth's crust and form 12% of the Earth's land surface. The lower continental crust is mostly metamafic-rock and pelite which have reached the granulite facies . The middle continental crust

12980-402: The world, varying in complexity and fidelity. Book VIII constitutes an atlas of regional maps. The maps include a recapitulation of some of the values given earlier in the work, which were intended to be used as captions to clarify the map's contents and maintain their accuracy during copying. Maps based on scientific principles had been made in Europe since the time of Eratosthenes in

13098-566: The zonal schemes, based on index minerals, that were pioneered by the British geologist, George Barrow . The metamorphic facies is not usually considered when classifying metamorphic rock based on protolith, mineral mode, or texture. However, a few metamorphic facies produce rock of such distinctive character that the facies name is used for the rock when more precise classification is not possible. The chief examples are amphibolite and eclogite . The British Geological Survey strongly discourages

13216-535: Was 10° east of Ptolemy's, he adds some places, and his latitudes differ. C.A. Nallino suggests that the work was not based on Ptolemy but on a derivative world map, presumably in Syriac or Arabic . The coloured map of al-Maʾmūm constructed by a team including al-Khwārazmī was described by the Persian encyclopædist al-Masʿūdī around 956 as superior to the maps of Marinus and Ptolemy, probably indicating that it

13334-661: Was 180 degrees. Prior to the 16th century, knowledge of geography in the Ottoman Empire was limited in scope, with almost no access to the works of earlier Islamic scholars that superseded Ptolemy. His Geography would again be translated and updated with commentary into Arabic under Mehmed II , who commissioned works from Byzantine scholar George Amiroutzes in 1465 and the Florentine humanist Francesco Berlinghieri in 1481. There are two related errors: This suggests Ptolemy rescaled his longitude data to fit with

13452-433: Was built along similar mathematical principles. It included 4530 cities and over 200 mountains. Despite beginning to compile numerous gazetteers of places and coordinates indebted to Ptolemy, Muslim scholars made almost no direct use of Ptolemy's principles in the maps which have survived. Instead, they followed al-Khwārazmī's modifications and the orthogonal projection advocated by Suhrāb's early 10th-century treatise on

13570-621: Was constructed in 1841. In the 20th century a solar panel was installed in the lighthouse's 29-metre (95 ft) column, providing a 50-kilometre (31 mi) field of vision. The International Coordinating Council of UNESCO 's Man and the Biosphere Programme (MAB), meeting in Dresden (Germany) from 28 June to 1 July, while adding 18 new sites, included the Berlengas to the World Network of Biosphere Reserves (WNBR): in

13688-419: Was important in metamorphism. This hypothesis was tested by his friend, James Hall , who sealed chalk into a makeshift pressure vessel constructed from a cannon barrel and heated it in an iron foundry furnace. Hall found that this produced a material strongly resembling marble , rather than the usual quicklime produced by heating of chalk in the open air. French geologists subsequently added metasomatism ,

13806-410: Was once positioned on that horizon. These observations suggest significant variations in the mean sea level, possibly as a result of quaternary glaciations . Additionally, Berlenga Grande has a poorly developed drainage network, (when precipitation occurs, rainwater is taken and falls directly into the sea in cascades ), which clearly evidences that the erosion rate of the granitic massif is lower than

13924-584: Was understood by Ptolemy to be a port on the Sinus Magnus, or Great Gulf, the actual Gulf of Thailand, at eight and a half degrees north of the Equator, on the coast of Cambodia, which is where he located it in his Canon of Famous Cities . It was the easternmost port reached by shipping trading from the Graeco-Roman world to the lands of the Far East. In Ptolemy's later and better-known Geography ,

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