The Moghra Oasis is an uninhabited oasis in the northeastern part of the

Qattara Depression The Qattara Depression () is a depression (geology), depression in northwestern Egypt, specifically in the Matruh Governorate. The depression is part of the Western Desert (Egypt), Western Desert of Egypt. The Qattara Depression lies below sea ...

in the Western Desert of Egypt. It has a lake containing brackish water, salt marshes and a swamp with reeds.

Geography

The Qattara Depression is about below sea level and is shaped like a teardrop, with Moghra Oasis in its northeastern corner. The floor of the Depression consists of

salt marsh A salt marsh, saltmarsh or salting, also known as a coastal salt marsh or a tidal marsh, is a coastal ecosystem in the upper coastal intertidal zone between land and open saltwater or brackish water that is regularly flooded by the tides. I ...

es and

dry lake A dry lake bed, also known as a playa (), is a basin or depression that formerly contained a standing surface water body, which disappears when evaporation processes exceed recharge. If the floor of a dry lake is covered by deposits of alkalin ...

beds that flood occasionally and there are also large areas of windblown sand. Moghra Oasis consists of a lake containing brackish water some below sea level. Adjoining it are

es and some ''

Phragmites ''Phragmites'' () is a genus of four species of large perennial plant, perennial reed (plant), reed Poaceae, grasses found in wetlands throughout temperate and tropical regions of the world. Taxonomy The World Checklist of Selected Plant Famili ...

'' swamps. To the south and west there are sand dunes near the lake and extensive sheets of sand beyond.

Geology

The water rises to the surface from an

aquifer An aquifer is an underground layer of water-bearing material, consisting of permeability (Earth sciences), permeable or fractured rock, or of unconsolidated materials (gravel, sand, or silt). Aquifers vary greatly in their characteristics. The s ...

in the

Nubian sandstone The Nubian Sandstone is a variety of sedimentary rock deposited on the Precambrian basement in the eastern Sahara, north-east Africa and Arabian Peninsula. It consists of continental sandstone with thin beds of marine limestones, and marls. The N ...

, but its precise source is unclear as the

Nubian Sandstone Aquifer System The Nubian Sandstone Aquifer System (NSAS) is the world's largest known fossil water aquifer system. It is located underground in the Eastern end of the Sahara desert and spans the political boundaries of four countries in north-eastern Africa. N ...

is at great depths in this area. Just to the north of the oasis is a cliff which gives its name to the Moghra Formation, a thick layer of clastic sedimentary rocks with some minor carbonate interbeds. This formation contains

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

s of

vertebrate Vertebrates () are animals with a vertebral column (backbone or spine), and a cranium, or skull. The vertebral column surrounds and protects the spinal cord, while the cranium protects the brain. The vertebrates make up the subphylum Vertebra ...

s and plants; large mammals found here include

hyaenodonts Hyaenodontidae ("hyena teeth") is a family of placental mammals in the extinct superfamily Hyaenodontoidea. Hyaenodontids arose during the early Eocene and persisted well into the early Miocene. Fossils of this group have been found in Asia, Nor ...

Megistotherium ''Megistotherium'' is an extinct genus of hyaenodont belonging to the family Hyainailouridae that lived in Africa and possibly Asia as well. It first appeared in Early Miocene to late Middle Miocene from 22.5 to 12.0 million years ago, existing ...

'' and '' Hyaenaelurus''. These

fluvial A river is a natural stream of fresh water that flows on land or inside caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of its course if it ru ...

deposits are likely to have come from a river system which opened into the Nile Delta at the Moghra Oasis.

Ecology

To the south of the lake, the saltmarsh gradually merges into saline flats largely devoid of vegetation. There are three main species in this plant community, each dominating its own concentric zone; ''

Zygophyllum album ''Zygophyllum album'' (synonym ''Tetraena alba'') is a species of plant in the family Zygophyllaceae which is found in arid regions of Africa and the Arabian Peninsula. It is a salt tolerant plant and dominates many of the plant communities in wh ...

'', ''

Nitraria retusa ''Nitraria retusa'', commonly known as Nitre bush, is a salt-tolerant and drought-resistant shrub in the family Nitrariaceae. It can grow to heights of , although it seldom exceeds more than 1 m in height. It produces small white/green colou ...

'' and ''

Tamarix nilotica ''Tamarix nilotica'', the Nile tamarisk is a species of shrub or small tree in the tamarisk family. It is found in arid parts of North Africa and the Middle East, particularly areas with high salinity. It forms part of the dune stabilisation pro ...

''. The most important variables affecting the distribution and structure of the communities are the moisture content of the soil and the salinity. In the outer zone, where the salinity is low and the surface is friable, small scattered plants of ''Zygophyllum album'' occur. In the innermost part of this zone the plants are larger and more crowded and they sometimes form hummocks. Here they are associated with ''T. nilotica'', ''

Alhagi maurorum ''Alhagi maurorum'' is a species of legume commonly known, variously, as camelthorn, Caspian manna,The name ''Alhagi maurorum'', replacing Linnaeus' ''Hedysarum alhagi'', was first published in ''Vorlesungen der Churpfälzischen physicalisch-ö ...

'' and ''N. retusa''. The next zone is dominated by ''N. retusa'' which shows a wide range of tolerances to moisture and salinity conditions. Among sand dunes it forms hummocks and plays an important role in stabilising dunes. In the outer fringes of the zone it is associated with ''Z. album'' and ''T. nilotica'' while on the inner fringes, where the water table is high but the soil has a low salinity level, the community includes ''

Phragmites australis ''Phragmites australis'', known as the common reed, is a species of flowering plant in the grass family Poaceae. It is a wetland grass that can grow up to tall and has a cosmopolitan distribution worldwide. Description ''Phragmites australis' ...

'', '' Juncus rigidus'', '' Sporobolus spicatus'' and ''Z. album''. The ''T. nilotica'' dominated area forms a scrub community on the outer fringes of the dune zone surrounding the salt flats, where it is associated with ''A. maurorum'', ''

Cressa cretica ''Cressa cretica'' is a species of flowering plant in the morning glory family. It is found in northern and central Africa, southern Europe and western Asia, as well as parts of southeastern Asia and Australia. It has long been used in tradition ...

'', ''N. retusa'' and ''Z album''. There are a few abandoned groves of

date palm ''Phoenix dactylifera'', commonly known as the date palm, is a flowering-plant species in the palm family Arecaceae, cultivated for its edible sweet #Fruits, fruit called dates. The species is widely cultivated across North Africa, northern A ...

s in the sandy areas.

References

{{Egypt oasis areas Oases of Egypt Western Desert (Egypt)