The
Strait of Gibraltar (
ArabicArabic is a Central Semitic language, thus related to and classified alongside other Semitic languages such as Hebrew and the Neo-Aramaic languages. In terms of speakers, the Arabic macrolanguage is the largest member of the Semitic language family. It is spoken by more than 280 million people as...
: مضيق جبل طارق,
SpanishSpanish or Castilian is a Romance language in the Ibero-Romance group that originated in northern Spain and gradually spread in the Kingdom of Castile, evolving into the principal language of government and trade in the Iberian peninsula...
:
Estrecho de Gibraltar) is a narrow
straitA strait or straits is a narrow, navigable channel of water that connects two larger navigable bodies of water. It most commonly refers to a channel of water that lies between two land masses, but it may also refer to a navigable channel through a body of water that is otherwise not navigable, for...
that connects the
Atlantic OceanThe Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about 106.4 million square kilometres , it covers approximately one-fifth of the Earth's surface and about one-quarter of its water surface area. The first part of its name refers to the Atlas of Greek...
to the
Mediterranean SeaThe Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by Africa, and on the east by the Levant. The sea is technically a part of the Atlantic Ocean, although it...
and separates
SpainSpain , officially the Kingdom of Spain , is a country located in southwestern Europe on the Iberian Peninsula.
[The Spanish constitution does not establish any official denomination of the country, even though España , Estado español and Nación española are used interchangeably...]
from
MoroccoMorocco, officially the Kingdom of Morocco, is a country located in North Africa with a population of nearly 32 million and an area just under . Its capital is Rabat, and its largest city is Casablanca. Morocco has a coast on the Atlantic Ocean that reaches past the Strait of Gibraltar into the...
. The name comes from
GibraltarThe Rock of Gibraltar is a monolithic limestone promontory located in Gibraltar, off the southwestern tip of Europe on the Iberian Peninsula. It is 426 metres high. The Rock is Crown property of the United Kingdom, and borders Spain...
, which in turn originates from the
ArabicArabic is a Central Semitic language, thus related to and classified alongside other Semitic languages such as Hebrew and the Neo-Aramaic languages. In terms of speakers, the Arabic macrolanguage is the largest member of the Semitic language family. It is spoken by more than 280 million people as...
Jebel Tariq (meaning "Tariq's mountain"), albeit the Arab name for the Strait is
Bab el-Zakat or "Gate of Charity". It is also erroneously known as the
Straits of Gibraltar, or
STROG (
Strait
Of
Gibraltar), in
navalA navy is the branch of a nation's armed forces principally designated for naval warfare and amphibious warfare; namely, lake- or ocean-borne combat operations and related functions...
use and as "
Pillars of HerculesThe Pillars of Hercules was the phrase that was applied in Antiquity to the promontories that flank the entrance to the Strait of Gibraltar. The northern Pillar is the Rock of Gibraltar in the British overseas territory of Gibraltar...
" (
GreekGreek , an independent branch of the Indo-European family of languages, is the language of the Greeks. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. In its ancient form, it is the language of classical...
: Ηράκλειες Στήλες) in the ancient world.
Europe and Africa are separated by 14.24 km (7.7
nautical mileThe nautical mile is a unit of length corresponding approximately to one minute of arc of latitude along any meridian....
s) of ocean at the strait's narrowest point.
The
Strait of Gibraltar (
ArabicArabic is a Central Semitic language, thus related to and classified alongside other Semitic languages such as Hebrew and the Neo-Aramaic languages. In terms of speakers, the Arabic macrolanguage is the largest member of the Semitic language family. It is spoken by more than 280 million people as...
: مضيق جبل طارق,
SpanishSpanish or Castilian is a Romance language in the Ibero-Romance group that originated in northern Spain and gradually spread in the Kingdom of Castile, evolving into the principal language of government and trade in the Iberian peninsula...
:
Estrecho de Gibraltar) is a narrow
straitA strait or straits is a narrow, navigable channel of water that connects two larger navigable bodies of water. It most commonly refers to a channel of water that lies between two land masses, but it may also refer to a navigable channel through a body of water that is otherwise not navigable, for...
that connects the
Atlantic OceanThe Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about 106.4 million square kilometres , it covers approximately one-fifth of the Earth's surface and about one-quarter of its water surface area. The first part of its name refers to the Atlas of Greek...
to the
Mediterranean SeaThe Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by Africa, and on the east by the Levant. The sea is technically a part of the Atlantic Ocean, although it...
and separates
SpainSpain , officially the Kingdom of Spain , is a country located in southwestern Europe on the Iberian Peninsula.
[The Spanish constitution does not establish any official denomination of the country, even though España , Estado español and Nación española are used interchangeably...]
from
MoroccoMorocco, officially the Kingdom of Morocco, is a country located in North Africa with a population of nearly 32 million and an area just under . Its capital is Rabat, and its largest city is Casablanca. Morocco has a coast on the Atlantic Ocean that reaches past the Strait of Gibraltar into the...
. The name comes from
GibraltarThe Rock of Gibraltar is a monolithic limestone promontory located in Gibraltar, off the southwestern tip of Europe on the Iberian Peninsula. It is 426 metres high. The Rock is Crown property of the United Kingdom, and borders Spain...
, which in turn originates from the
ArabicArabic is a Central Semitic language, thus related to and classified alongside other Semitic languages such as Hebrew and the Neo-Aramaic languages. In terms of speakers, the Arabic macrolanguage is the largest member of the Semitic language family. It is spoken by more than 280 million people as...
Jebel Tariq (meaning "Tariq's mountain"), albeit the Arab name for the Strait is
Bab el-Zakat or "Gate of Charity". It is also erroneously known as the
Straits of Gibraltar, or
STROG (
Strait
Of
Gibraltar), in
navalA navy is the branch of a nation's armed forces principally designated for naval warfare and amphibious warfare; namely, lake- or ocean-borne combat operations and related functions...
use and as "
Pillars of HerculesThe Pillars of Hercules was the phrase that was applied in Antiquity to the promontories that flank the entrance to the Strait of Gibraltar. The northern Pillar is the Rock of Gibraltar in the British overseas territory of Gibraltar...
" (
GreekGreek , an independent branch of the Indo-European family of languages, is the language of the Greeks. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. In its ancient form, it is the language of classical...
: Ηράκλειες Στήλες) in the ancient world.
Europe and Africa are separated by 14.24 km (7.7
nautical mileThe nautical mile is a unit of length corresponding approximately to one minute of arc of latitude along any meridian....
s) of ocean at the strait's narrowest point. The Strait's depth ranges between which possibly interacted with the lower mean sea level of the last major glaciation 20,000 years before present when the level of the sea was believed to be 110 to 120 metres (361 to 394 ft) lower. Ferries cross between the two continents every day in as little as 35 minutes. The Spanish side of the Strait is protected under
El Estrecho Natural ParkEl Estrecho Natural Park is a nature reserve in Spain located on the northern side of the Strait of Gibraltar....
.
Location
On the northern side of the Strait is
SpainSpain , officially the Kingdom of Spain , is a country located in southwestern Europe on the Iberian Peninsula.
[The Spanish constitution does not establish any official denomination of the country, even though España , Estado español and Nación española are used interchangeably...]
and
GibraltarGibraltar is a self-governing British overseas territory located on the southern end of the Iberian Peninsula and Europe at the entrance of the Mediterranean overlooking the Strait of Gibraltar. The territory covers and shares a land border with Spain to the north...
(a British exclave in the
Iberian PeninsulaThe Iberian Peninsula, or Iberia, is located in the extreme southwest of Europe and includes modern-day Spain, Portugal, Andorra and Gibraltar and a very small area of France. It is the westernmost of the three major southern European peninsulas—the Iberian, Italian, and Balkan peninsulas...
), while on the southern side is
MoroccoMorocco, officially the Kingdom of Morocco, is a country located in North Africa with a population of nearly 32 million and an area just under . Its capital is Rabat, and its largest city is Casablanca. Morocco has a coast on the Atlantic Ocean that reaches past the Strait of Gibraltar into the...
and
CeutaCeuta is an autonomous city of Spain located on the North African side of the Strait of Gibraltar, on the Mediterranean, which separates it from the Spanish mainland. The area of Ceuta is approximately ....
(a Spanish exclave in
North AfricaNorth Africa or Northern Africa is the northernmost region of the African continent, linked by the Sahara to Sub-Saharan Africa.Geopolitically, the UN definition of Northern Africa includes the following seven countries or territories; Algeria, Egypt, Libya, Morocco, Sudan, Tunisia,Mauritania, and...
). Its boundaries were known in antiquity as the
Pillars of HerculesThe Pillars of Hercules was the phrase that was applied in Antiquity to the promontories that flank the entrance to the Strait of Gibraltar. The northern Pillar is the Rock of Gibraltar in the British overseas territory of Gibraltar...
. There are several islets, such as the
disputedA territorial dispute is a disagreement over the possession/control of land between two or more states, or over the possession or control of land by one state after it has conquered it from a former state no longer currently recognized by the occupying power....
Isla PerejilFor the armed conflict, see Perejil Island crisisThe Perejil Island is a small, uninhabited rocky islet located in the Strait of Gibraltar. Its sovereignty is disputed between Spain and Morocco. It was the subject of an armed incident between the two countries in 2002.-Name:Spanish Isla Perejil...
, that are claimed by Morocco from Spain.
Due to its location, the Strait is widely used for
illegal immigrationIllegal immigration is immigration across national borders in a way that violates the immigration laws of the destination country. Illegal immigrants are also known as illegal aliens to differentiate them from legal aliens...
from Africa to Europe.
Geology
Around 5.9 million years ago, the connection between the Mediterranean Sea and the Atlantic Ocean along the Bethic and Rifan Corridor was progressively restricted until its total closure, effectively causing the salinity of the Mediterranean to periodically fall within the
gypsumGypsum is a very soft mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO
4·2H
2O.-Crystal varieties:...
and salt deposition range, during what is known as the
Messinian Salinity CrisisThe Messinian Salinity Crisis, also referred to as the Messinian Event, is a period when the Mediterranean Sea evaporated partly or completely during the Messinian period of the Miocene epoch, 5.96 million years ago.-Naming:...
. In this
water chemistryChemistry is the science concerned with the composition, behavior, structure, and properties of matter, as well as the changes it undergoes during chemical reactions...
environment, dissolved mineral concentrations, temperature and stilled water currents combined properly and occurred regularly to precipitate many mineral salts in sea floor bedded layers. The resultant accumulation of various huge salt and mineral deposits about the Mediterranean basin are directly linked to this era. It is not believed this process took a long time geologically, lasting only 500-600 thousand-years, for it is further estimated that were the straits closed even at today's higher sea level, most water in the
Mediterranean basinThe Mediterranean Basin comprises the lands around and surrounded by the Mediterranean Sea. In biogeography, the Mediterranean Basin refers to the lands around the Mediterranean Sea that have a Mediterranean climate, with mild, rainy winters and hot, dry summers, which supports characteristic...
would evaporate within only a thousand years; as it is believed to have done then, and such an event would lay down similar mineral deposits as those such as the fabulous salt mines now found under the sea floor off
SicilySicily is the largest island in the Mediterranean Sea. It is an autonomous region of Italy. Several much smaller islands surrounding it are considered to be part of Sicily....
. After a lengthy period of restricted intermittent or no water exchange between the Atlantic Ocean and Mediterranean basin, approximately 5.33 million years ago, the Atlantic-Mediterranean connection was completely reestablished through the Strait of Gibraltar, and has remained open ever since. Current geologic expectations are the strait will close again fairly soon as figured in geologic time scales as the African plate continues north, but such an event is thousands of years away in human relevant calendar time scales.
Communications
The Strait is an important
shipping routeA shipping route is a trade route used by merchant ships.Early routes usually were coastal in nature as navigators had to rely on the coastal landmarks. As the knowledge of navigation and mapmaking increased, shipping routes became less dependent on coastal landmarks and spanned to larger seas and...
from the Mediterranean to the Atlantic. There are ferries that operate between Spain and Morocco across the strait, as well as between Spain and
CeutaCeuta is an autonomous city of Spain located on the North African side of the Strait of Gibraltar, on the Mediterranean, which separates it from the Spanish mainland. The area of Ceuta is approximately ....
and
GibraltarGibraltar is a self-governing British overseas territory located on the southern end of the Iberian Peninsula and Europe at the entrance of the Mediterranean overlooking the Strait of Gibraltar. The territory covers and shares a land border with Spain to the north...
to
TangierTangier or Tangiers [
pronounce] is a city of northern Morocco with a population of about 700,000...
.
Tunnel across the strait
In December 2003, Spain and Morocco agreed to explore the construction of an
underseaUnderwater is a term describing the realm below the surface of water where the water exists in a natural feature such as an ocean, sea, lake, pond, or river. Three quarters of the planet Earth is covered by water. A majority of the planet's solid surface is abyssal plain, at depths between 4000...
railRail transport is the conveyance of passengers and goods by means of wheeled vehicles running along railways or railroads. Rail transport is part of the logistics chain, which facilitates international trade and economic growth...
tunnelA tunnel is an underground passageway. The definition of what constitutes a tunnel is not universally agreed upon. However, in general tunnels are at least twice as long as they are wide. In addition, they should be completely enclosed on all sides, save for the openings at each end...
to connect their rail systems across the Strait. The gauge of the rail would be to match the proposed construction and conversion of significant parts of the existing broad gauge system to
standard gaugeThe standard gauge is a widely-used rail gauge. Approximately 60% of the world's existing railway lines are built to this gauge...
.
Inflow and outflow
On a net basis, water continually flows eastward through the Strait of Gibraltar, due to an evaporation rate within the Mediterranean basin higher than the combined inflow of all the rivers that empty into it. The
sillThe Camarinal Sill is the sill separating the Mediterranean Sea and the Atlantic Ocean.This threshold is the shallowest seafloor pass between the Iberian Peninsula and Africa. It is located near the Gibraltar Strait at , at an elevation of −280 m. Marine waters must climb to that depth when...
of the Strait of Gibraltar acts to limit mixing between the cold, less saline Atlantic water and the warm Mediterranean waters. The latter are so much saltier that they sink below the constantly incoming Atlantic water and form a highly saline (
thermohalineThe term thermohaline circulation refers to the part of the large-scale ocean circulation that is driven by global density gradients created by surface heat and freshwater fluxes....
, both warm and salty) bottom water, called the Mediterranean outflow. A density boundary separates the layers at about depth. It flows out and down the continental slope, losing salinity, until it equilibrates after mixing at a depth of about . The Mediterranean outflow water can be traced for thousands of
kilometreThe kilometre , symbol km is a unit of length in the metric system, equal to one thousand metres and is therefore exactly equal to the distance travelled by light in free space in of a second....
s before losing its identity.
Internal waveInternal waves are gravity waves that oscillate within, rather than on the surface of, a fluid medium. They arise from perturbations to hydrostatic equilibrium, where balance is maintained between the force of gravity and the buoyant restoring force. A simple example is a wave propagating on the...
s (waves at the density boundary layer) are common in the strait. Like traffic merging on a highway, the water flow is constricted in both directions because it must pass over a shallow submarine barrier, the
Camarinal SillThe Camarinal Sill is the sill separating the Mediterranean Sea and the Atlantic Ocean.This threshold is the shallowest seafloor pass between the Iberian Peninsula and Africa. It is located near the Gibraltar Strait at , at an elevation of −280 m. Marine waters must climb to that depth when...
. When large tidal flows enter the Strait, internal waves are set off at the Camarinal Sill as the high tide relaxes. The waves—sometimes with heights up to travel eastward. Even though the waves occur at great depth and the height of the waves at the surface is almost nothing, they can be traced in the
sunglintSunglint is a phenomenon that occurs when the sun reflects off the surface of the ocean at the same angle that a satellite sensor is viewing the surface. In the affected area of the image, smooth ocean water becomes a silvery mirror, while rougher surface waters appear dark...
because they concentrate the biological films on the water surface, creating slight differences in roughness. The waves flow eastward, refract around coastal features; can be traced for as much as , and sometimes create interference patterns with refracted waves.
External links