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 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 to the southeast, the Adamawa Plateau to the northeast and the Cameroon coastal plain to the south.

Topography and geology

The Western High Plateau lies along the Cameroon line, 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 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

es, including the Bamboutos Mountains, Mount Oku and Mount Kupe. 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 plateau gives way to the Adamawa Plateau 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. The base is

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 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 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 in the West Region is 20°C. Toward the north, rainfall levels are reduced as the Sudan climate becomes predominant. The Western High Plateau's relief and high rainfall make it a major watershed for Cameroon. Important rivers in the region include the Manyu, which rises in the Bamboutos Mountains and becomes the Cross River on its lower course, and the Nkam, which is known as the Wouri River on its lower course. The region gives rise to important tributaries to the Sanaga River. 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

. 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 in the West Region is 80 metres high. Crater lakes 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 ...

forms the dominant vegetation. This consists of grassfields—leading to the name ''Bamenda grassfields'' around the city of Bamenda—and short shrubs and trees that shed their foliage during the dry season as a defence against brush fires and dry weather. Raffia palms 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