The Great Rift Valley is a series of contiguous geographic

trench A trench is a type of excavation or in the ground that is generally deeper than it is wide (as opposed to a wider gully, or ditch), and narrow compared with its length (as opposed to a simple hole or pit). In geology, trenches result from ero ...

es, approximately in total length, that runs from

Lebanon Lebanon ( , ar, لُبْنَان, translit=lubnān, ), officially the Republic of Lebanon () or the Lebanese Republic, is a country in Western Asia. It is located between Syria to the north and east and Israel to the south, while Cyprus lie ...

in Asia to

Mozambique Mozambique (), officially the Republic of Mozambique ( pt, Moçambique or , ; ny, Mozambiki; sw, Msumbiji; ts, Muzambhiki), is a country located in southeastern Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi ...

in Southeast Africa. While the name continues in some usages, it is rarely used in

geology Geology () is a branch of natural science concerned with Earth and other Astronomical object, astronomical objects, the features or rock (geology), rocks of which it is composed, and the processes by which they change over time. Modern geology ...

as it is considered an imprecise merging of separate though related rift and fault systems. This valley extends northward for 5,950 km through the eastern part of Africa, through the

Red Sea The Red Sea ( ar, البحر الأحمر - بحر القلزم, translit=Modern: al-Baḥr al-ʾAḥmar, Medieval: Baḥr al-Qulzum; or ; Coptic: ⲫⲓⲟⲙ ⲛ̀ϩⲁϩ ''Phiom Enhah'' or ⲫⲓⲟⲙ ⲛ̀ϣⲁⲣⲓ ''Phiom ǹšari''; ...

, and into

Western Asia Western Asia, West Asia, or Southwest Asia, is the westernmost subregion of the larger geographical region of Asia, as defined by some academics, UN bodies and other institutions. It is almost entirely a part of the Middle East, and includes A ...

. Several deep, elongated lakes, called

ribbon lake A ribbon lake is a long and deep, finger-shaped lake, usually found in a glacial trough. As such, a ribbon lake is one of a number of glacial landscapes, including arêtes, corries, rock lips, rock basins and terminal moraines. Such a lake's ...

s, exist on the floor of this rift valley: Lakes Malawi, Rudolf and Tanganyika are examples of such lakes. The region has a unique ecosystem and contains a number of Africa's wildlife parks. Great_rift_valley

The term Great Rift Valley is most often used to refer to the valley of the

East African Rift The East African Rift (EAR) or East African Rift System (EARS) is an active continental rift zone in East Africa. The EAR began developing around the onset of the Miocene, 22–25 million years ago. In the past it was considered to be part of ...

, the divergent plate boundary which extends from the

Afar Triple Junction The Afar Triple Junction (also called the Afro-Arabian Rift System) is located along a divergent plate boundary dividing the Nubian, Somali, and Arabian plates. This area is considered a present-day example of continental rifting leading to s ...

southward through

eastern Africa East Africa, Eastern Africa, or East of Africa, is the eastern subregion of the African continent. In the United Nations Statistics Division scheme of geographic regions, 10-11-(16*) territories make up Eastern Africa: Due to the historica ...

, and is in the process of splitting the

African Plate The African Plate is a major tectonic plate that includes much of the continent of Africa (except for its easternmost part) and the adjacent oceanic crust to the west and south. It is bounded by the North American Plate and South American Plate ...

into two new and separate plates. Geologists generally refer to these evolving plates as the Nubian Plate and the Somali Plate.

Theoretical extent

Today these rifts and faults are seen as distinct, although connected, but originally, the Great Rift Valley was thought to be a single feature that extended from

in the north to

in the south, where it constitutes one of two distinct physiographic provinces of the East African mountains. It included what today is called the Lebanese section of the Dead Sea Transform, the Jordan Rift Valley, Red Sea Rift and the

. These rifts and faults were formed 35 million years ago.

Asia

The northernmost part of the Rift corresponds to the central section of what is called today the Dead Sea Transform (DST) or Rift. This midsection of the DST forms the

Beqaa Valley The Beqaa Valley ( ar, links=no, وادي البقاع, ', Lebanese ), also transliterated as Bekaa, Biqâ, and Becaa and known in classical antiquity as Coele-Syria, is a fertile valley in eastern Lebanon. It is Lebanon's most important ...

in Lebanon, separating the Mount Lebanon range from the Anti-Lebanon Mountains. Further south it is known as the

Hula Valley The Hula Valley ( he, עמק החולה, translit. ''Emek Ha-Ḥula''; also transliterated as Huleh Valley, ar, سهل الحولة) is an agricultural region in northern Israel with abundant fresh water, which used to be Lake Hula, prior to ...

separating the

Galilee Galilee (; he, הַגָּלִיל, hagGālīl; ar, الجليل, al-jalīl) is a region located in northern Israel and southern Lebanon. Galilee traditionally refers to the mountainous part, divided into Upper Galilee (, ; , ) and Lower Gali ...

mountains and the

Golan Heights The Golan Heights ( ar, هَضْبَةُ الْجَوْلَانِ, Haḍbatu l-Jawlān or ; he, רמת הגולן, ), or simply the Golan, is a region in the Levant spanning about . The region defined as the Golan Heights differs between di ...

. The

Jordan River The Jordan River or River Jordan ( ar, نَهْر الْأُرْدُنّ, ''Nahr al-ʾUrdunn'', he, נְהַר הַיַּרְדֵּן, ''Nəhar hayYardēn''; syc, ܢܗܪܐ ܕܝܘܪܕܢܢ ''Nahrāʾ Yurdnan''), also known as ''Nahr Al-Shariea ...

begins here and flows southward through Lake Hula into the

Sea of Galilee The Sea of Galilee ( he, יָם כִּנֶּרֶת, Judeo-Aramaic: יַמּא דטבריא, גִּנֵּיסַר, ar, بحيرة طبريا), also called Lake Tiberias, Kinneret or Kinnereth, is a freshwater lake in Israel. It is the lowest ...

Israel Israel (; he, יִשְׂרָאֵל, ; ar, إِسْرَائِيل, ), officially the State of Israel ( he, מְדִינַת יִשְׂרָאֵל, label=none, translit=Medīnat Yīsrāʾēl; ), is a country in Western Asia. It is situated ...

. The Rift then continues south through the Jordan Rift Valley into the

Dead Sea The Dead Sea ( he, יַם הַמֶּלַח, ''Yam hamMelaḥ''; ar, اَلْبَحْرُ الْمَيْتُ, ''Āl-Baḥrū l-Maytū''), also known by other names, is a salt lake bordered by Jordan to the east and Israel and the West Ban ...

on the

Jordan Jordan ( ar, الأردن; tr. ' ), officially the Hashemite Kingdom of Jordan,; tr. ' is a country in Western Asia. It is situated at the crossroads of Asia, Africa, and Europe, within the Levant region, on the East Bank of the Jordan Rive ...

ian border. From the Dead Sea southwards, the Rift is occupied by the Wadi

Arabah The Arabah, Araba or Aravah ( he, הָעֲרָבָה, ''hāʿĂrāḇā''; ar, وادي عربة, ''Wādī ʿAraba''; lit. "desolate and dry area") is a loosely defined geographic area south of the Dead Sea basin, which forms part of the bord ...

, then the

Gulf of Aqaba The Gulf of Aqaba ( ar, خَلِيجُ ٱلْعَقَبَةِ, Khalīj al-ʿAqabah) or Gulf of Eilat ( he, מפרץ אילת, Mifrátz Eilát) is a large gulf at the northern tip of the Red Sea, east of the Sinai Peninsula and west of the Arabian ...

, and then the

. Off the southern tip of Sinai in the Red Sea, the Dead Sea Transform meets the Red Sea Rift which runs the length of the Red Sea. The Red Sea Rift comes ashore to meet the

and the

Aden Ridge The Aden Ridge is a part of an active oblique rift system located in the Gulf of Aden, between Somalia and the Arabian Peninsula to the north. The rift system marks the divergent boundary between the Somali and Arabian tectonic plates, extending ...

in the

Afar Depression The Afar Triangle (also called the Afar Depression) is a geological depression caused by the Afar Triple Junction, which is part of the Great Rift Valley in East Africa. The region has disclosed fossil specimens of the very earliest hominins; ...

of East Africa. The junction of these three rifts is called the

Africa

The East African Rift follows the Red Sea to the end before turning inland into the

Ethiopian highlands The Ethiopian Highlands is a rugged mass of mountains in Ethiopia in Northeast Africa. It forms the largest continuous area of its elevation in the continent, with little of its surface falling below , while the summits reach heights of up to . ...

, dividing the country into two large and adjacent but separate mountainous regions. In Kenya, Uganda, and the fringes of South Sudan, the Great Rift runs along two separate branches that are joined to each other only at their southern end, in Southern

Tanzania Tanzania (; ), officially the United Republic of Tanzania ( sw, Jamhuri ya Muungano wa Tanzania), is a country in East Africa within the African Great Lakes region. It borders Uganda to the north; Kenya to the northeast; Comoro Islands ...

along its border with

Zambia Zambia (), officially the Republic of Zambia, is a landlocked country at the crossroads of Central, Southern and East Africa, although it is typically referred to as being in Southern Africa at its most central point. Its neighbours are t ...

. The two branches are called the

Western Rift Valley The Albertine Rift is the western branch of the East African Rift, covering parts of Uganda, the Democratic Republic of the Congo (DRC), Rwanda, Burundi and Tanzania. It extends from the northern end of Lake Albert to the southern end of Lake Tan ...

and the Eastern Rift Valley. The Western Rift, also called the Albertine Rift, is bordered by some of the highest mountains in Africa, including the Virunga Mountains, Mitumba Mountains, and

Ruwenzori Range The Ruwenzori, also spelled Rwenzori and Rwenjura, are a range of mountains in eastern equatorial Africa, located on the border between Uganda and the Democratic Republic of the Congo. The highest peak of the Ruwenzori reaches , and the range' ...

. It contains the

Rift Valley lakes The Rift Valley lakes are a series of lakes in the East African Rift valley that runs through eastern Africa from Ethiopia in the north to Malawi in the south, and includes the African Great Lakes in the south. These include some of the world's ...

, which include some of the deepest lakes in the world (up to deep at

Lake Tanganyika Lake Tanganyika () is an African Great Lake. It is the second-oldest freshwater lake in the world, the second-largest by volume, and the second-deepest, in all cases after Lake Baikal in Siberia. It is the world's longest freshwater lake. T ...

). Much of this area lies within the boundaries of national parks such as Virunga National Park in the

Democratic Republic of Congo The Democratic Republic of the Congo (french: République démocratique du Congo (RDC), colloquially "La RDC" ), informally Congo-Kinshasa, DR Congo, the DRC, the DROC, or the Congo, and formerly and also colloquially Zaire, is a country in ...

Rwenzori National Park Rwenzori Mountains National Park is a Ugandan national park and UNESCO World Heritage Site located in the Rwenzori Mountains. Almost in size, the park has Africa's third highest mountain peak and many waterfalls, lakes, and glaciers. The ...

and

Queen Elizabeth National Park Queen Elizabeth National Park is a national park in Uganda. Location Queen Elizabeth National Park (QENP) is in the Western Region of Uganda, spanning the districts of Kasese, Kamwenge, Rubirizi, and Rukungiri. The park is approximately by ...

in Uganda, and Volcanoes National Park in

Rwanda Rwanda (; rw, u Rwanda ), officially the Republic of Rwanda, is a landlocked country in the Great Rift Valley of Central Africa, where the African Great Lakes region and Southeast Africa converge. Located a few degrees south of the Equator ...

Lake Victoria Lake Victoria is one of the African Great Lakes. With a surface area of approximately , Lake Victoria is Africa's largest lake by area, the world's largest tropical lake, and the world's second-largest fresh water lake by surface area after ...

is considered to be part of the rift valley system although it actually lies between the two branches. All of the

African Great Lakes The African Great Lakes ( sw, Maziwa Makuu; rw, Ibiyaga bigari) are a series of lakes constituting the part of the Rift Valley lakes in and around the East African Rift. They include Lake Victoria, the second-largest fresh water lake in th ...

were formed as the result of the rift, and most lie in territories within the rift. In

Kenya ) , national_anthem = " Ee Mungu Nguvu Yetu"() , image_map = , map_caption = , image_map2 = , capital = Nairobi , coordinates = , largest_city = Nairobi , ...

, the valley is deepest to the north of

Nairobi Nairobi ( ) is the capital and largest city of Kenya. The name is derived from the Maasai phrase ''Enkare Nairobi'', which translates to "place of cool waters", a reference to the Nairobi River which flows through the city. The city proper ...

. As the lakes in the Eastern Rift have no outlet to the sea and tend to be shallow, they have a high

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2 ...

content as the evaporation of water leaves the salts behind. For example,

Lake Magadi Lake Magadi is the southernmost lake in the Kenyan Rift Valley, lying in a catchment of faulted volcanic rocks, north of Tanzania's Lake Natron. During the dry season, it is 80% covered by soda and is well known for its wading birds, including ...

has high concentrations of soda (

sodium carbonate Sodium carbonate, , (also known as washing soda, soda ash and soda crystals) is the inorganic compound with the formula Na2CO3 and its various hydrates. All forms are white, odourless, water-soluble salts that yield moderately alkaline solutions ...

) and

Lake Elmenteita Lake Elmenteita is a soda lake, in the Great Rift Valley, about 120 km northwest of Nairobi, Kenya. Geography Elmenteita is derived from the Maasai word , meaning "dust place", a reference to the dryness and dustiness of the area, espe ...

Lake Bogoria Lake Bogoria (formerly Lake Hannington) is a saline, alkaline lake that lies in a volcanic region in a half-graben basin south of Lake Baringo, Kenya, a little north of the equator. Lake Bogoria, like Lake Nakuru, Lake Elementeita, and Lake Ma ...

, and

Lake Nakuru Lake Nakuru is one of the Rift Valley lakes at an elevation of above sea level. It lies to the south of Nakuru, in the rift valley of Kenya and is protected by Lake Nakuru National Park. The lake's abundance of algae used to attract a vast qu ...

are all strongly

alkaline In chemistry, an alkali (; from ar, القلوي, al-qaly, lit=ashes of the saltwort) is a basic, ionic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a ...

, while the freshwater springs supplying

Lake Naivasha Lake Naivasha is a freshwater lake in Kenya, outside the town of Naivasha in Nakuru County, which lies north west of Nairobi. It is part of the Great Rift Valley. The name derives from the local Maasai name ''Nai'posha'', meaning "rough wate ...

are essential to support its current biological variety. The southern section of the Rift Valley includes

Lake Malawi Lake Malawi, also known as Lake Nyasa in Tanzania and Lago Niassa in Mozambique, is an African Great Lake and the southernmost lake in the East African Rift system, located between Malawi, Mozambique and Tanzania. It is the fifth largest f ...

, the third-deepest freshwater body in the world, which reaches in depth and separates the Nyassa plateau of Northern Mozambique from Malawi; it ends in the

Zambezi The Zambezi River (also spelled Zambeze and Zambesi) is the fourth-longest river in Africa, the longest east-flowing river in Africa and the largest flowing into the Indian Ocean from Africa. Its drainage basin covers , slightly less than ha ...

valley.

References

External links

Article on geology.com
* {{Authority control Great Rift Valley, * Rifts and grabens Landforms of Africa Landforms of the Middle East Landforms of Israel Landforms of Syria Landforms of Egypt Landforms of Lebanon Landforms of Ethiopia Landforms of Kenya Landforms of Saudi Arabia Landforms of Yemen Landforms of Tanzania Landforms of the Democratic Republic of the Congo Landforms of Uganda Landforms of Burundi Geology of Israel Geology of Syria Geology of Egypt Geology of Lebanon Geology of Ethiopia Geology of Kenya Geology of Saudi Arabia Geology of Yemen Geology of Tanzania Geology of the Democratic Republic of the Congo Geology of Uganda Geology of Burundi Geology of Africa Physiographic provinces

Theoretical extent

Asia

Africa

See also

References

Further reading

External links