The Eastern Desert (Archaically known as Arabia or the Arabian Desert) is the part of the Sahara desert that is located east of the Nile river. It spans 223,000 square kilometres (86,000 sq mi) of North-Eastern Africa and is bordered by the Nile River to the west and the Red Sea and Gulf of Suez to the east. It extends through Egypt, Eritrea, Sudan and Ethiopia. The Eastern Desert is also known as the Red Sea Hills. It consists of a mountain range which runs parallel to the coast, broad sedimentary plateaus extending from either side of the mountains and the Red Sea coast. The rainfall, climate, vegetation and animal life sustained in the Desert varies between these regions. The Eastern Desert has been a mining site for building materials and precious and semi-precious metals throughout history. Historically, it has contained many trade routes leading to and from the Red Sea, including the Suez Canal.
- Coastal vegetation
- Littoral salt marsh
Geography of Eastern Desert
Between 100 and 35 million years ago, the area now the Eastern Desert was underwater, covered by the Tethys Ocean. During the Oligocene period, around 34 million years ago, the land began to tilt, and the coastline was pushed back to the North and west. Concurrently, the basement complex to the east was uplifted, forming the mountain range of the Desert. In this same sequence of land movements, a rift, now the Red Sea, was opened up.
The mountain range of the Eastern Desert runs between 80 and 137 kilometres (50 and 85 mi) inland from and parallel to the Red Sea Coast. It has peaks around 1,500 metres (4,900 ft) above sea level. The southern mountains are predominantly igneous rock, while the mountains to the North are limestone. Separating the mountains are wide wadis which allow for the runoff of rainfall from the mountains to the Red Sea and the Nile River. The tallest peak of the mountain range is Gebel Shayeb EI-Banat, at 2,184 metres (7,165 ft) above sea level. Other significant peaks include Jebel Erba (2,217 metres (7,274 ft)) Jabal Oda (2,160 metres (7,090 ft)), Jabal Shaib al Banat (2,087 metres (6,847 ft)), Jebel Hamata (1,961 metres (6,434 ft)), Gebel Amm Anad (1,782 metres (5,846 ft)), South Galala (1,464 metres (4,803 ft)), and North Galala (1,274 metres (4,180 ft)).
Sedimentary plateaus run on either side of the mountains. Generally, the Northern sections of these plateaus have a limestone base, while the Southern areas are sandstone. The plateaus between the Nile River and the mountains are also known as the inland Eastern Desert. They are subdivided into the Cairo-Suez Desert, The Limestone Desert, The Sandstone (Edfu-Kom Ombo), and the Nubian Desert.
Red Sea coast
The Red Sea coastland is the easternmost part of the Eastern Desert, running between Eritrea and the Gulf of Suez. The coastline varies between 30 and 175 kilometres (19 and 109 mi) in width from the base of the mountain range.
The Eastern Desert has a semi-arid/arid/hyper-arid climate. On average, the region receives less than 25 millimetres (0.98 in) of rainfall per year in irregular patterns. Most of the precipitation occurs during the winter months around the mountains. The presence of the mountains can create a rain shadow for the rest of the Desert, contributing to the arid environment.
Average temperatures are between 14 and 21 °C (57 and 70 °F) in winter (November–March) and 23.1 and 23.1 °C (73.6 and 73.6 °F) in summer (May–September). The weather is typically sunny. However, sandstorms can occur, usually between March and June. The storms (khamsins) are caused by tropical air moving up from Sudan, accompanied by strong winds and an increased temperature. ‘Khamsin’ comes from the Arabic word meaning fifty, as the storms occur on an average of fifty days a year.
Carbon dating of samples of fossil tufas, a type of limestone deposited in the presence of high groundwater levels, had revealed that there have historically been two periods when the Eastern Desert was significantly wetter than it is today. These occurred in the late Pleistocene age, around 100,000 and the middle Holocene age, about 6000 years ago. The most recent wet period resulted from summer monsoonal rains that moved over the Desert from the Indian Ocean. During these times, some areas of the land were swamped. The mountains and desert plateaus could also sustain more vegetation and animals. In between these periods, the desert climate has remained mostly arid, as it is today.
The vegetation growing in the Eastern Desert is classified as either ephemeral or perennial. Ephemeral vegetation is plants which usually have a single-season lifespan due to their dependence on rain. Perennial plants live for two or more years.
There are three main ecosystems within the coastal region of the Eastern Desert: littoral salt marsh, coastal Desert and coastal mountains. The presence of sea spray, tidal movements and salt water seepage means that vegetation in these areas must be well adapted to living in a saline environment.
Littoral salt marsh
The salt marsh is created as mud builds up on tidal flats, and plants grow on the mud, making it a more stable and permanent ecosystem. This area’s two main types of vegetation are mangrove and salt marsh.
Avicennia marina or grey mangrove is the dominant mangrove plant in the Red Sea area. It grows consistently along a large stretch of the Red Sea coast but is rarely seen to the North of the Egyptian city, Hurghada. Rhizophora mucronata, or loop-root mangrove, also grows co-dominantly with A.Marina in some areas along the coast, but it is less prevalent. The loop-root mangrove is taller than the grey mangrove; thus, they form a two-tiered canopy of leaves in areas where they grow together. Small plants such as Cymodocea Ciliata and Halophila oualis typically initiate the undergrowth of the mangrove community.
The salt marsh vegetation comprises a mix of shrub, succulent and grass species. The growth of these plants often creates coastal dunes as the root systems hold the sand in place when other areas are left exposed to wind erosion.
- Halocnemum strobilaceum is a woody sub-shrub which grows in the mud flats and on the sandy shoreline. It is most common on the northern section of the coast, near the Gulf of Suez.
- Arthrocaulon macrostachyum (syn. Arthrocnemum glaucum) is a flowering shrub which grows in similar areas to H. strobilaceum but is less prevalent in the North.
- Limonium pruinosum, also known as a species of sea lavender, grows commonly around the Gulf of Suez. Also, from this family, the species of Limonium axillare contributes to up to 50% of vegetation cover on the South coast.
- Tamarix nilotica is a bush that grows in various conditions along the Red Sea coast. The roots stabilise the sand to form dunes.
- Zygophyllum album is a frequently occurring succulent community which is tolerant to different soil conditions and thus, is found all along the coast.
- Halopeplis perfoliata is a succulent species which commonly grows in the southern region of the Red Sea coast.
- Nitraria retusa and Suaeda monoica are succulent shrubs commonly located within the northern 700 km of the coast. They are separate communities but grow together in the same area and extend inland to the coastal desert plain area.
- Suaeda monoica grows in similar areas to N.retusa. However, it is also found further south and is a common feature of the Eritrean and Sudanese coastal regions.
- Aeluropus brevifolius and Aeluropus lagopoides are two species of creeping grasses that usually grow in dense patches along the coast but are also known to form tall masses of interwoven roots and sand.
- Sporobolus spicatus, also known as salt grass, grows inland from A.brevifolius and A.lagopoides, where sand deposits are more profound, and the soil is less saline.
- Halopyrum mucronatum grows on hills and dunes. It is rare and is only found in a few locations along the coast.
Coastal desert vegetation grew in the band between the littoral salt marsh and the base of the coastal mountains. Compared to the littoral salt marsh area, the soil is non-saline and arid. The growing vegetation relies on the drainage of water from the mountains via wadis. As a result, the growth of plants is seasonal, unlike in the littoral salt marsh. A greater variety of vegetation also grows in the area compared to the salt marsh area. Perennial vegetation is made up of succulents, grasses and woody shrub species. The ephemeral vegetation includes a mix of grasses, succulents and herbaceous plants.
The vegetation cover on the coastal mountains is denser than in the coastal desert. There are over 400 plant species within the coastal mountain’s ecosystem, including shrubs, herbs and ferns. The distribution of these species varies subtly as the altitude changes.
The plants which grow on the inland plateaus vary significantly in their distribution and species due to the difference in sandstone and limestone rock bases and the varying amount of rain and runoff water from the wadis.
The wildlife of the Eastern Desert is quite different from that of the Western Desert, as the presence of the Nile River and the Red Sea Mountains provide variable eco-regions. Small mammals such as the fennec fox, golden spiny mouse, bushy-tailed jird, jerboa and other rodents live on the desert’s plateaus. Other larger mammals include the hyrax, Egyptian mongoose and the Egyptian wolf. The Red Sea Hills provide a unique mountainous habitat which increases the diversity of fauna in the Eastern Desert. Species in the mountains include the aoudad, a mountain-dwelling species of sheep, the Nubian ibex and the Dorcus gazelle. The mountain range also provides a habitat for various birdlife, including the golden eagle and the bearded vulture, which are rarely found in other Sahara areas. The Nile Valley is a central location for bird migration, and there are more than 200 species of birds pass through the western side of the Eastern desert during the migration seasons.
Natural resources and mining
The mining of precious metals dates back to Ancient Egyptian times and has carried on in the Eastern Desert until the present day. From the early Pharaonic era (3000 BC), copper and gold were mined from the Desert and used to make tools, jewellery, and embellishment. It was not until much later, around 1000 BC, that iron was discovered and began to be mined. Wadis were used as routes to cart the mined materials back to the civilisation. There were also mines for precious rocks such as emeralds and amethysts discovered by the Ancient Egyptians and used during the Roman and Islamic periods. As well as precious materials, valuable building and sculpting materials have been mined from the Eastern desert, such as limestone, granite and marble. Today, most mining in and around the Eastern Desert is for crude oil and natural gas.
Around 25,000 BC, the land underwent a significant climatic change, transforming the grassy plains into a desert. This made the land much less habitable, and as a result of this change, nomads who had inhabited the land that is now the Eastern Desert were driven towards the Nile River.
Pharaonic Egypt (3000–30 BC)
The Desert established trade routes from the Nile to the Red Sea. Notably, there was a route between the Nile River and Mersa Gawasis, an Ancient Egyptian port. There were also many mines and quarries along this route. Boats were carried in pieces across the desert through the wadis and then set up once they reached the port to embark on expeditions. The Ancient Egyptians exploited the desert resources of copper, gold, iron and precious stones. As well as for trade, they used these resources to improve their society and burials.
Roman Period (30 BC – 395 CE)
Commercial trade increased further during this time, and more trade routes were established across the desert. Red Sea ports were points of embarkation for trade with India. During the Ptolemaic and Roman periods, the chief port was Berenice Troglodytica, and the Via Hadriana led from Berenice to Antinoöpolis on the Nile. Items traded diversified during this period to include goods such as fabrics and pearls. “Imperial Porphyry” was quarried at Mons Claudianus into the Byzantine era. The Romans set up multiple ports along the red sea coast to transport materials. Roman soldiers lived and worked at these ports. Their primary sources of food were pigs, donkeys and camels.
The Eastern Desert is a popular site for tours, safaris and other expeditions. Mining also still occurs in the Desert.