The Great Escarpment: Angola's Natural Wonder And Guardian

The Great Escarpment is a significant geological formation in Southern Africa, extending into Angola in the west. It is a vast geographical feature, with its northernmost reaches extending into Angola, forming a boundary between the country's central plateau and its coastal regions. The Escarpment's formation dates back approximately 160 to 180 million years, shaped by tectonic activity, erosion, and the gradual rising of the central Southern African plateau. In Angola, the Great Escarpment consists of two primary mountain ranges, the Serra da Leba and the Serra de Chela, with the latter being one of the steepest stretches of the African Great Escarpment.

Formation and history

The Great Escarpment is a major geological formation in Southern Africa. It is an enormous geographic feature that ranges southwards through Namibia, cuts through South Africa, and extends north along the border of Mozambique and Zimbabwe. In the west, it extends northward into Angola.

The Great Escarpment is old, having formed along with the formation of the Atlantic Ocean some 160 to 180 million years ago. At the time, the area was part of the South Gondwana continent. A mantle plume caused bulging of the continental crust, resulting in the topography of Southern Africa that we see today. Within 10 to 20 million years, rift valleys formed on either side of the central bulge and flooded to become the proto-Atlantic and proto-Indian Oceans. The steep walls of these rift valleys formed escarpments that surrounded the newly formed Southern African subcontinent.

Over the past 20 million years, Southern Africa has experienced massive uplifting, with most of the plateau rising above 1,000 meters. The Great Escarpment has also moved inland through erosion processes. The history of the Great Escarpment signifies two tectonic episodes: the rifted margin and the basin and swells formation.

The Great Escarpment in Angola consists of two primary mountain ranges: the Serra da Leba and the Serra de Chela. The Serra da Chela mountains are the country's steepest and most dramatic. The immediate mountainous drop from the plateau is steepest in this region. The highest point in Angola, however, is Mount Moco in the Huambo Province.

Geological features

The Great Escarpment is a significant geological formation in Southern Africa, with a large portion of it falling within South Africa's borders. It extends northward to form the border between Mozambique and Zimbabwe in the east and continues in the same direction into Namibia and Angola in the west. The Great Escarpment is an enormous geographical feature that spans Southern Africa, with its northernmost reaches extending into Angola.

The Great Escarpment is a topographical feature that consists of steep slopes descending from the high central Southern African plateau towards the oceans surrounding Southern Africa on three sides. The escarpment separates the region's highland interior plateau from the relatively narrow coastal strip. The immediate mountainous drop from the plateau is most pronounced in Angola, with the Serra da Chela mountains being the steepest and most dramatic in the country. The highest point in Angola is Mount Moco, located in the Huambo Province, which is outside of the Great Escarpment.

The Great Escarpment's formation is estimated to have occurred around 160-180 million years ago, coinciding with the formation of the Atlantic Ocean and the bulging of the continental crust in the area that became Southern Africa. The steep mountains of the Great Escarpment are the result of the gradual rising of the plateau over the past 20 million years, shaped by the slow process of erosion from coastal winds. The escarpment is defined by the hardness of the plateau edge rocks, with distinct and sharp definitions where hard rocks overlie soft rocks and more gradual, indistinct definitions where rocks are of undifferentiated hardness.

The Great Escarpment has a unique valley landscape with parallel ridges that separate long valleys. The Drakensberg area of the escarpment, which is the most well-known section, features basalt lava overlaying softer sandstone. The Serra da Chela in Angola, the Schwarzrand in Namibia, and the Khomas Highlands in Namibia are also notable stretches of the Great Escarpment with distinct geological features.

Flora and fauna

The Angolan Escarpment Zone is a physical feature that forms part of the Great Escarpment of Southern Africa. The zone includes elements of all the major biomes of Angola, with vegetation ranging from tropical rainforests to desert landscapes. The Escarpment Zone is of biogeographical importance as it reflects the diverse environments of the habitats and biota of the Escarpment.

The Angolan Escarpment Zone extends across 1,400 km from northern Cabinda to the Cunene River. The climate of the zone varies from humid in the north, with up to 1,600 mm of precipitation per year, to arid in the south, where it forms the interior margin of the Namib Desert, receiving less than 250 mm of rainfall. The geology of the zone is varied, but mostly comprises crystalline Precambrian rocks such as gneisses, quartzites, schists, granites, gabbros, amphibolites, and migmatites.

The Escarpment Zone includes several prominent scarps, where the landscape is broken by abrupt increases in altitude over a few kilometres. It is also characterised by the presence of many inselbergs – isolated geomorphological features that rise as steep-sided hills or mountains formed of resistant bedrock, surrounded by lower-elevation lowlands.

The flora of the Escarpment Zone is diverse, ranging from tropical rainforests to arid savannas and woodlands. The zone is estimated to host over 8,500 plant species, including 1,460 endemic species. The flora is predominantly Guineo-Congolian and Zambezian, with some Afromontane elements. The Central Escarpment features arid savannas, woodlands, thickets, and dry forests, with Acacia, Annona, Cochlospermum, Erythrina, and Piliostigma savannas, and Brachystegia, Julbernardia, Combretum, and Terminalia woodlands. The Northern Escarpment features semi-deciduous Guineo-Congolian forests, with tallgrass savannas of Western Congolian Forest/Savanna Mosaic communities. The Southern Escarpment features arid woodlands and thickets, including Acacia, Adansonia, and Colophospermum, with Albizia, Brachylaena, Combretum, Commiphora, and Tarchonanthus woodlands and thickets at higher elevations.

The fauna of the Escarpment Zone is also diverse, with at least 126 endemic vertebrate species. The bird fauna is particularly notable, with the zone providing important insights into the evolution of African forests. The zone is home to several endemic bird species, including the red-crested turaco, the national bird of Angola, which is common in the region. Other endemic bird species include the Gabela Akalat, Pulitzer's Longbill, Gabela Bushshrike, Gabela Helmetshrike, Monteiro's Bushshrike, Grey-striped Francolin, and White-fronted Wattle-eye. The Central Escarpment is also home to small antelope species known as duikers and nocturnal tree pangolins. Historically, the low forests of the Escarpment Zone were home to larger mammals such as elephants, lions, and cheetahs, but these were sadly hunted and poached to extinction during Angola's 30-year civil war.

Climate

The climate of the Angolan Escarpment Zone varies from humid in the north, with up to 1600 mm of precipitation per year, to arid in the south, where it borders the Namib Desert. The Escarpment Zone's annual rainfall averages about 1,200 mm in northern Angola and on the Angolan Planalto, dropping to less than 100 mm in far southern Namibia. Rainfall is highest in northern Angola, with two rainy seasons: November and December, and March and April. The southern areas are much drier than the north due to the combined effects of high evapotranspiration and low rainfall.

The Angolan Escarpment is part of the Great Escarpment of Southern Africa, which stretches for 5,000 km and has climates ranging from tropical summer rainfall to warm temperate winter rainfall, with annual rainfall between 250 and 1600 mm. The Escarpment rises from 500 to 2000 m above sea level over most of its range, with the highest peaks in Angola reaching 2620 m.

The Great Escarpment separates the highland interior plateau of Southern Africa from the narrow coastal strip. In Angola, it divides the country's central plateau, home to savanna landscapes, from the mountains and hills that descend towards the coastal regions. The Escarpment's steep mountains were shaped by the gradual rising of the plateau and erosion by coastal winds over millions of years.

Threats to the environment

The Great Escarpment, a major geological formation in Southern Africa, is a significant topographical feature in Angola. The Angolan section of the Great Escarpment consists of two primary mountain ranges, the Serra da Leba and the Serra de Chela. The Great Escarpment has been shaped by geological processes over millions of years, and it is a result of the combination of this escarpment and the aridity of Southern Africa that there are no navigable rivers in South Africa.

The Great Escarpment of Southern Africa faces several man-made threats, which are impacting the environment. One of the main threats is the construction of dams to meet the increasing demand for water and electricity due to the growing human population in and around the area. This has led to the loss of natural habitats and disturbances in the climate. The need for economic development and water for irrigation and agriculture has also put pressure on the environment.

Freshwater areas are being exploited for commercial fishing and industrial waste dumping, with many wastes containing radioactive materials. This has led to the degradation of water quality and further loss of natural habitats.

Climate change is another significant threat to the environment in Angola. The country is vulnerable to natural hazards such as flooding, erosion, droughts, and epidemics, which are expected to worsen with changing climatic conditions. Angola's coastline, home to over 50% of the country's population, is particularly at risk due to rising sea levels. The current and future effects of climate change include erratic rainfall, droughts, and increased storm frequency, all of which threaten the livelihoods of coastal communities.

To address these challenges, organizations like the UN Environment Programme, the United Nations Development Programme, and the Angolan Ministry of Environment are working to help coastal communities adapt to climate change. Their efforts include restoring ecological habitats, promoting climate-resilient land management, and establishing early warning climate forecasting systems.

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