Alboran Sea | |
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Mar de Alborán | |
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Location | Southern Europe and North Africa |
Coordinates | 36°0′N3°0′W / 36.000°N 3.000°W |
River sources | Guadalhorce River, Guadalfeo River, Adra River (Spain) and Nekor River (Morocco) |
Ocean/sea sources | Atlantic Ocean |
Basin countries | Algeria, Gibraltar (UK), Morocco, and Spain |
Average depth | 445 metres (1,460 ft) |
Max. depth | 1,500 metres (4,900 ft) |
Settlements | Málaga, Marbella, Motril, Almería and Cartagena, Spain Alhucemas and Nador, Morocco, Gibraltar |
The Alboran Sea is the westernmost portion of the Mediterranean Sea, lying between the Iberian Peninsula and the north of Africa (Spain on the north and Morocco and Algeria on the south). The Strait of Gibraltar, which lies at the west end of the Alboran Sea, connects the Mediterranean with the Atlantic Ocean.
Its average depth is 445 metres (1,460 ft) and maximum depth is 1,500 metres (4,900 ft).
The International Hydrographic Organization defines the limits of the Alboran Sea as follows: [1]
On the West. The Eastern limit of the Strait of Gibraltar: A line joining from tip (Europa Point) of Cap Gibraltar in Europe ( 36°6.5′N5°20.7′W / 36.1083°N 5.3450°W ) to the tip of the Península de Almina of Ceuta in Africa ( 35°54′N5°18′W / 35.900°N 5.300°W ).
On the East. A line joining from Cabo de Gata in Andalusia in Europe ( 36°43.3′N2°11.6′W / 36.7217°N 2.1933°W ) to Cap Fegalo, near Oran, Algeria in Africa ( 35°36′N1°12′W / 35.600°N 1.200°W ).
Several small islands dot the sea, including the eponymous Isla de Alborán. Most, even those close to the African shore, belong to Spain.
The Alboran domain, the seafloor beneath the Alboran Sea (known as the internal zones) together with the surrounding mountains (known as the external zones; the Gibraltar Arc and Atlas Mountains), is mostly made of continental crust and marks the westernmost terminus of the terranes that were subducted between the African and Eurasian Plates when the Tethys Ocean closed. Reoccurring earthquakes at a depth of about 600 km (370 mi) indicate that this subduction is ongoing and that complex interactions between the lithosphere and mantle are forming the region. [2] The internal zones are made of Late Paleozoic to Triassic rocks that were piled up during the Tertiary and has been extended since the Early Miocene. [3]
The seafloor is morphologically complex with several sub-basins, including three main sub-basins named West, East, and South Alboran Basins, ridges, and seamounts. The most prominent structure in the Alboran Sea is the 180 km long (110 mi) Alboran Ridge which stretches southwest from the volcanic Alborán Island. [4]
Surface currents in the Alboran Sea, influenced by the prevailing winds, flow eastward, bringing water from the Atlantic into the Mediterranean; deeper subsurface currents flow westward, carrying saltier Mediterranean water over the Gibraltar sill into the Atlantic. Thus there is typically a vertical rotary circulation, also known as a gyre, in the Alboran Sea as a result of this exchange of water. [5]
The Alboran Sea is a transition zone between ocean and sea, containing a mix of Mediterranean and Atlantic species. The Alboran Sea is habitat for the largest population of bottlenose dolphins and the last population of harbour porpoises in the western Mediterranean, and is the most important feeding grounds for loggerhead sea turtles in Europe. The Alboran sea also hosts important commercial fisheries, including sardines and swordfish. In 2003, the World Wildlife Fund raised concerns about the widespread drift net fishing endangering populations of dolphins, turtles, as well as other marine animals. In 2023, the European Union, Morocco, and Algeria agreed to ban bottom fishing practices around Cabliers Bank, protecting the only cold-water coral reef known to be growing in the Mediterranean. [6]
An arc of mountains, known as the Gibraltar Arc, wraps around the northern, western and southern sides of the Alboran Sea. The Gibraltar Arc is made up of the Baetic Cordillera of Southern Spain and the Rif Mountains of Morocco. These mountains, known to ecologists as the Baetic-Rifan complex, comprise one of the Mediterranean's biodiversity hotspots; like the Alboran Sea, the Baetic-Rifan complex represents a transition between the Mediterranean and Atlantic (Macaronesian) ecological zones. The moderating influence of the Atlantic has allowed many relict species in the Baetic and Rif mountains to survive the climatic fluctuations of the last few million years that have caused them to become extinct elsewhere around the Mediterranean basin.
There are some small islands in the sea: [7]
The Atlantic Ocean is the second-largest of the world's five oceanic divisions, with an area of about 85,133,000 km2 (32,870,000 sq mi). It covers approximately 17% of Earth's surface and about 24% of its water surface area. During the Age of Discovery, it was known for separating the New World of the Americas from the Old World of Afro-Eurasia.
The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the east by the Levant in West Asia, on the north by Anatolia in West Asia and Southern Europe, on the south by North Africa, and on the west almost by the Morocco–Spain border. The Mediterranean Sea covers an area of about 2,500,000 km2 (970,000 sq mi), representing 0.7% of the global ocean surface, but its connection to the Atlantic via the Strait of Gibraltar—the narrow strait that connects the Atlantic Ocean to the Mediterranean Sea and separates the Iberian Peninsula in Europe from Morocco in Africa—is only 14 km (9 mi) wide.
Morocco is the northwesternmost country which spans from the Mediterranean Sea and Atlantic Ocean on the north and the west respectively, into large mountainous areas in the interior, to the Sahara desert in the far south. Morocco is a Northern African country, located in the extreme northwest of Africa on the edge of continental Europe. The Strait of Gibraltar separates Spain from Morocco with a 13 kilometres (8.1 mi) span of water. Morocco borders the North Atlantic Ocean to the west, and the western Mediterranean Sea to the north, and has borders with Algeria and disputed Western Sahara.
Spain is a country located in southwestern Europe occupying most of the Iberian Peninsula. It also includes a small exclave inside France called Llívia, as well as the Balearic Islands in the Mediterranean, the Canary Islands in the Atlantic Ocean 108 km (67 mi) off northwest Africa, and five places of sovereignty on and off the coast of North Africa: Ceuta, Melilla, Islas Chafarinas, Peñón de Alhucemas, and Peñón de Vélez de la Gomera.
The Strait of Gibraltar is a narrow strait that connects the Atlantic Ocean to the Mediterranean Sea and separates Europe from Africa. The two continents are separated by 7.7 nautical miles at its narrowest point. Ferries cross between the two continents every day in as little as 35 minutes. The Strait's depth ranges between 300 and 900 metres.
The Alhucemas Islands is a group of islands and one of the Spanish plazas de soberanía just off the Moroccan coast in the Alboran Sea.
Peñón de Vélez de la Gomera is a Spanish exclave and rocky tidal island in the western Mediterranean Sea connected to the Moroccan shore by a sandy isthmus. It is also connected to a smaller islet to the east, La Isleta, by a rocky isthmus. The tidal island was named Hajar Badis and was connected to the town of Badis.
Alboran Island is a small islet of Spain in the Alboran Sea, part of the western Mediterranean Sea, about 56 kilometres north of the Moroccan coast and 85 kilometres from the Spanish mainland. The main buildings are an automated lighthouse built in the 19th century, a small cemetery, and a harbour.
The Baetic System or Betic System is one of the main systems of mountain ranges in Spain. Located in the southern and eastern Iberian Peninsula, it is also known as the Cordilleras Béticas or Baetic Mountains. The name of the mountain system derives from the ancient Roman region of Baetica, one of the Imperial Roman provinces of ancient Hispania.
In the Messinian salinity crisis the Mediterranean Sea went into a cycle of partial or nearly complete desiccation (drying-up) throughout the latter part of the Messinian age of the Miocene epoch, from 5.96 to 5.33 Ma. It ended with the Zanclean flood, when the Atlantic reclaimed the basin.
In biogeography, the Mediterranean basin, also known as the Mediterranean region or sometimes Mediterranea, is the region of lands around the Mediterranean Sea that have mostly a Mediterranean climate, with mild to cool, rainy winters and warm to hot, dry summers, which supports characteristic Mediterranean forests, woodlands, and scrub vegetation.
The Middle Atlas is a mountain range in Morocco. It is part of the Atlas mountain range, a mountainous region with more than 100,000 km2, 15 percent of its landmass, rising above 2,000 metres. The Middle Atlas is the northernmost and second highest of three main Atlas Mountains chains of Morocco. To south, separated by the Moulouya and Um Er-Rbiâ rivers, lies the High Atlas. The Middle Atlas form the westernmost end of a large plateaued basin extending eastward into Algeria, also bounded by the Tell Atlas to the north and the Saharan Atlas to the south, both lying largely in Algeria. North of the Middle Atlas and separated by the Sebou River, lie the Rif mountains which are an extension of the Baetic System, which includes the Sierra Nevada in the south of Spain. The basin of the Sebou is not only the primary transportation route between Atlantic Morocco and Mediterranean Morocco but is an area, watered by the Middle Atlas range, that constitutes the principal agricultural region of the country.
The geology of the Iberian Peninsula consists of the study of the rock formations on the Iberian Peninsula, connected to the rest of the European landmass by the Pyrenees. The peninsula contains rocks from every geological period from the Ediacaran to the Quaternary, and many types of rock are represented. World-class mineral deposits are also found there.
The Gibraltar Arc is a geological region corresponding to an arcuate orogen surrounding the Alboran Sea, between the Iberian Peninsula and Africa. It consists of the Betic Cordillera, and the Rif. The Gibraltar Arc is located at the western end of the Mediterranean Alpine belt and formed during the Neogene due to convergence of the Eurasian and African plates.
The Azores–Gibraltar transform fault (AGFZ), also called a fault zone and a fracture zone, is a major seismic zone in the eastern Atlantic Ocean between the Azores and the Strait of Gibraltar. It is the product of the complex interaction between the African, Eurasian, and Iberian plates. The AGFZ produced these large-magnitude earthquakes and, consequently, a number of large tsunamis: 1755 Lisbon, 1761 Lisbon, 1816 North Atlantic, 1941 Gloria Fault earthquake, 1969 Horseshoe and 1975.
The Iberian plate is a microplate typically grouped with the Eurasian plate that includes the microcontinent Iberia, Corsica, Sardinia, the Balearic Islands, the Briançonnais zone of the Penninic nappes of the Alps, and the portion of Morocco north of the High Atlas Mountains. The Iberian plate is a part of the Eurasian plate.
The Morocco–Spain border consists of three non-contiguous lines totalling 18.5 km around the Spanish territories of Ceuta, Peñón de Vélez de la Gomera and Melilla. Spanish islets such as the Chafarinas or the Alhucemas are located off the Moroccan coast.
The Intercontinental Biosphere Reserve of the Mediterranean is the first of its type to be designated by the Man and the Biosphere Programme. It combines the Tingitan Peninsula in Morocco and the southern Iberian Peninsula of Andalusia. Both countries are located in a biogeographic region of deciduous forests and evergreen sclerophyllous scrub within the Mediterranean bioclimatic zone. The maritime area of the biosphere reserve is dominated by the Strait of Gibraltar, which links the two peninsulas. The reserve also encompasses natural and human communication routes between Africa and Europe.
The Zanclean flood or Zanclean deluge is theorized to have refilled the Mediterranean Sea 5.33 million years ago. This flooding ended the Messinian salinity crisis and reconnected the Mediterranean Sea to the Atlantic Ocean, although it is possible that even before the flood there were partial connections to the Atlantic Ocean. The re-connection marks the beginning of the Zanclean age which is the name given to the earliest age on the geologic time scale of the Pliocene.
The topographical relief of Spain is characterized by being quite high, with an average altitude of 660 meters above sea level, quite mountainous compared to other European countries and only surpassed by Switzerland, Austria, Albania, Montenegro, North Macedonia and the microstates of Andorra and Liechtenstein. In peninsular Spain, the terrain is articulated around a large Meseta Central that occupies most of the center of the Iberian Peninsula. Outside the plateau, there is the depression of the Guadalquivir river, located in the southwest of the peninsula, and the Ebro river depression, located in the northeast.