The Western High Plateau, Western Highlands or Bamenda Grassfields is a region of
Cameroon
Cameroon, officially the Republic of Cameroon, is a country in Central Africa. It shares boundaries with Nigeria to the west and north, Chad to the northeast, the Central African Republic to the east, and Equatorial Guinea, Gabon, and the R ...
characterised by high relief, cool temperatures, heavy rainfall and
savanna
A savanna or savannah is a mixed woodland-grassland (i.e. grassy woodland) biome and ecosystem characterised by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach th ...
vegetation. The region lies along the
Cameroon line
The Cameroon line (, , ) is a long chain of volcanoes that includes islands in the Gulf of Guinea and mountains on the African mainland, from Mount Cameroon on the coast towards Lake Chad on the northeast. They form a natural border between ea ...
and consists of
mountain range
A mountain range or hill range is a series of mountains or hills arranged in a line and connected by high ground. A mountain system or mountain belt is a group of mountain ranges with similarity in form, structure, and alignment that have aris ...
s and
volcano
A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.
On Earth, volcanoes are most oft ...
es made of
crystalline
A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macrosc ...
and
igneous rock
Igneous rock ( ), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rocks are formed through the cooling and solidification of magma or lava.
The magma can be derived from partial ...
. The region borders the
South Cameroon Plateau
The South Cameroon Plateau or Southern Cameroon Plateau () is the dominant geographical feature of Cameroon. The plateau lies south of the Adamawa Plateau and southeast of the Cameroon Range. It slopes south and west until giving way to the Camer ...
to the southeast, the
Adamawa Plateau
The Adamawa Plateau () is a plateau region in west-central Africa stretching from south-eastern Nigeria through north-central Cameroon ( Adamawa and North Provinces) to the Central African Republic. The part of the plateau that lies in Nigeria i ...
to the northeast and the Cameroon coastal plain to the south.
Topography and geology
The Western High Plateau lies along the
Cameroon line
The Cameroon line (, , ) is a long chain of volcanoes that includes islands in the Gulf of Guinea and mountains on the African mainland, from Mount Cameroon on the coast towards Lake Chad on the northeast. They form a natural border between ea ...
, a series of volcanic swells running from the
Atlantic Ocean
The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...
in the southwestern part of the plateau to the
Adamawa Plateau
The Adamawa Plateau () is a plateau region in west-central Africa stretching from south-eastern Nigeria through north-central Cameroon ( Adamawa and North Provinces) to the Central African Republic. The part of the plateau that lies in Nigeria i ...
in the northeast. The region is characterised by accidented relief of
massif
A massif () is a principal mountain mass, such as a compact portion of a mountain range, containing one or more summits (e.g. France's Massif Central). In mountaineering literature, ''massif'' is frequently used to denote the main mass of an ...
s and mountains. The Western High Plateau features several dormant
volcano
A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.
On Earth, volcanoes are most oft ...
es, including the
Bamboutos Mountains
The Bambouto massif or Bamboutos Mountains is a group of volcanoes based on a swell in the Cameroon Volcanic Line, located in the Western High Plateau of Cameroon, merging in the north with the Oku Volcanic Field.
Geology
The large volcanic comp ...
,
Mount Oku
Mount Oku, or Kilum Mountain, is the largest volcano in the Oku Massif, in the Cameroon Volcanic Line, located in the Oku region of the Western High Plateau of Cameroon.
It is the second highest mountain in mainland Central Africa.
The stratovo ...
and
Mount Kupe
Mount Kupe or Mont Koupé is a plutonic mountain in the Western High Plateau of Cameroon, part of the Cameroon line of volcanoes. It is the highest of the Bakossi Mountains, rising to .
The mountain is revered by the local Bakossi people as the ...
. The plateau rises in steps from the west. To the east, it terminates in mountains that range from 1,000 metres to 2,500 metres in height, terminating in the
South Cameroon Plateau
The South Cameroon Plateau or Southern Cameroon Plateau () is the dominant geographical feature of Cameroon. The plateau lies south of the Adamawa Plateau and southeast of the Cameroon Range. It slopes south and west until giving way to the Camer ...
. The plateau gives way to the
Adamawa Plateau
The Adamawa Plateau () is a plateau region in west-central Africa stretching from south-eastern Nigeria through north-central Cameroon ( Adamawa and North Provinces) to the Central African Republic. The part of the plateau that lies in Nigeria i ...
to the northeast, which is a larger but less accidented region.
The core of the plateau is made up of
volcanic rock
Volcanic rocks (often shortened to volcanics in scientific contexts) are rocks formed from lava erupted from a volcano. Like all rock types, the concept of volcanic rock is artificial, and in nature volcanic rocks grade into hypabyssal and me ...
, which is ringed by
plutonic rock
Intrusive rock is formed when magma penetrates existing rock, crystallizes, and solidifies underground to form ''intrusions'', such as batholiths, dikes, sills, laccoliths, and volcanic necks.Intrusive RocksIntrusive rocks accessdate: March ...
. The base is
crystalline
A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macrosc ...
and
metamorphic rock
Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock ( protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, caus ...
. The base rock is primarily
gneiss
Gneiss (pronounced ) is a common and widely distributed type of metamorphic rock. It is formed by high-temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. This rock is formed under p ...
and
granite
Granite ( ) is a coarse-grained (phanerite, phaneritic) intrusive rock, intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly coo ...
that dates to the
Precambrian period. A layer of
basalt
Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...
covers this. Vulcanism has created fertile black and brown soils. Erosion played a large role.
Climate and drainage
The plateau experiences an
equatorial climate
A tropical rainforest climate or equatorial climate is a tropical climate sub-type usually found within 10 to 15 degrees latitude of the equator. There are some other areas at higher latitudes, such as the coast of southeast Florida, United States ...
of the Cameroon type. The area experiences two major seasons: A long,
wet season
The wet season (sometimes called the rainy season or monsoon season) is the time of year when most of a region's average annual rainfall occurs. Generally, the season lasts at least one month. The term ''green season'' is also sometimes used a ...
of nine months, and a short,
dry season
The dry season is a yearly period of low rainfall, especially in the tropics. The weather in the tropics is dominated by the tropical rain belt, which moves from the northern to the southern tropics and back over the course of the year. The t ...
of three months. During the wet season, humid, prevailing
monsoon
A monsoon () is traditionally a seasonal reversing wind accompanied by corresponding changes in precipitation but is now used to describe seasonal changes in Atmosphere of Earth, atmospheric circulation and precipitation associated with annu ...
winds blow in from the west and lose their moisture upon hitting the region's mountains. Average rainfall per year ranges from 1,000 mm to 2,000 mm. High elevations give the region a cooler climate than the rest of Cameroon. For example, the average temperature at
Dschang
Dschang is a city located in the West (Ouest) Province of Cameroon, with an estimated population of 87,000 (est) in 2001, growing dramatically from 21,705 recorded in 1981. The 2006 Population is estimated to be 200,000 inhabitants.
Dschang is th ...
in the
West Region is 20°C. Toward the north, rainfall levels are reduced as the
Sudan climate
Sudan, officially the Republic of the Sudan, is a country in Northeast Africa. It borders the Central African Republic to the southwest, Chad to the west, Libya to the northwest, Egypt to the north, the Red Sea to the east, Eritrea and Ethiopi ...
becomes predominant.
The Western High Plateau's relief and high rainfall make it a major
watershed
Watershed may refer to:
Hydrology
* Drainage divide, the line that separates neighbouring drainage basins
* Drainage basin, an area of land where surface water converges (North American usage)
Music
* Watershed Music Festival, an annual country ...
for Cameroon. Important rivers in the region include the
Manyu, which rises in the
Bamboutos Mountains
The Bambouto massif or Bamboutos Mountains is a group of volcanoes based on a swell in the Cameroon Volcanic Line, located in the Western High Plateau of Cameroon, merging in the north with the Oku Volcanic Field.
Geology
The large volcanic comp ...
and becomes the
Cross River on its lower course, and the
Nkam
Nkam is a department of Littoral Province in Cameroon. The department covers an area of 6,291 km and as of 2001 had a total population of 66,979. The capital of the department lies at Yabassi.
Subdivisions
The department is divided admini ...
, which is known as the
Wouri River
The Wouri (also Vouri or Vuri) is a river in Cameroon. The Wouri forms at the confluence of the rivers Nkam River, Nkam and Makombé River, Makombé, northeast of the city of Yabassi. It then flows about southeast to the Wouri estuary at Douala ...
on its lower course. The region gives rise to important tributaries to the
Sanaga River
The Sanaga River (formerly ) is the largest river in Cameroon located in East Region (Cameroon), East Region, Centre Region (Cameroon), Centre Region and Littoral Region (Cameroon), Littoral Region. Its length is about from the confluence of Dj ...
. These rivers follow a Cameroon regime, a subtype of the equatorial regime of other southern
Cameroonian rivers. This means that the rivers experience a long, high-water period during the wet season and a short, low-water period during the dry season. The region's rivers ultimately empty into the
Atlantic Ocean
The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...
. The area's accidented geography gives rise to several
waterfall
A waterfall is any point in a river or stream where water flows over a vertical drop or a series of steep drops. Waterfalls also occur where meltwater drops over the edge
of a tabular iceberg or ice shelf.
Waterfalls can be formed in seve ...
s along these waterways.
Ekon Falls near
Nkongsamba
Nkongsamba is a city in western Cameroon. It is in the Moungo department, which is in the Littoral. As of the 2005 Census, the city had a population of 104,050. It is a centre for the farming of palm oil, bananas and coffee, and is between two ...
in the West Region is 80 metres high.
Crater lake
Crater Lake ( Klamath: ) is a volcanic crater lake in south-central Oregon in the Western United States. It is the main feature of Crater Lake National Park and is a tourist attraction for its deep blue color and water clarity. T ...
s dot the plateau, the result of dead volcanoes filling with water.
Flora
The Western High Plateau was once heavily forested. However, repeated cutting and burning by human beings has forced the forest back to areas along the waterways and has allowed grasslands to expand into the area.
Sudan
Sudan, officially the Republic of the Sudan, is a country in Northeast Africa. It borders the Central African Republic to the southwest, Chad to the west, Libya to the northwest, Egypt to the north, the Red Sea to the east, Eritrea and Ethiopi ...
savanna
A savanna or savannah is a mixed woodland-grassland (i.e. grassy woodland) biome and ecosystem characterised by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach th ...
forms the dominant vegetation. This consists of grassfields—leading to the name ''Bamenda grassfields'' around the city of
Bamenda
Bamenda, also known as Abakwa and Mankon Town, is a city in northwestern Cameroon and capital of the Northwest Region (Cameroon), Northwest Region. The city has a population of about six hundred thousand people and is located north-west of the C ...
—and short shrubs and trees that shed their foliage during the dry season as a defence against brush fires and dry weather.
Raffia palm
Raffia palms are members of the genus ''Raphia''. The Malagasy name is derived from ' "to squeeze juice". The genus contains about twenty species of palms native to tropical regions of Africa, and especially Madagascar, with one species ('' R ...
s grow in the valleys and depressions.
References
Sources
*
*
{{coord, 6, 30, N, 10, 30, E, dim:100000_region:CM-NW/CM-OU_type:landmark_source:dewiki, display=title
Plateaus of Cameroon
Highlands