The Moghra Oasis is an uninhabited oasis in the northeastern part of the Qattara Depression 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 marshes 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 exceeds recharge. If the floor of a dry lake is covered by deposits of alkaline c ...

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 salt marshes and some '' Phragmites'' 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 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 Nub ...

, 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. ...

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 fossils of vertebrates and plants; large mammals found here include hyaenodonts ''

Megistotherium ''Megistotherium'' ("greatest beast") is an extinct genus of hyainailourid hyaenodonts from paraphyletic subfamily Hyainailourinae that lived in Africa. Etymology The name of this genus comes and . The name of species ''Megistotherium osteo ...

'' and ''

Hyaenaelurus ''Hyainailouros'' ("hyena- cat") is an extinct polyphyletic genus of hyainailourid hyaenodont mammal of the polyphyletic tribe Hyainailourini within paraphyletic subfamily Hyainailourinae, that lived during the early to middle Miocene, of which ...

''. These

fluvial In geography and geology, fluvial processes are associated with rivers and streams and the deposits and landforms created by them. When the stream or rivers are associated with glaciers, ice sheets, or ice caps, the term glaciofluvial or fluviog ...

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 ''Tetraena alba'' (synonym ''Zygophyllum album'') 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 w ...

'', ''

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, camelthorn-bush, Caspian manna, and Persian mannaplant. This shrub is native to the region extending from the Mediterranean to Russia, but has been introduced ...

'' 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'', '' Juncus rigidus'', ''

Sporobolus spicatus ''Sporobolus spicatus'', also known as salt grass, is a halophyte. Distribution This bunchgrass is distributed: *in dryer parts of Africa such as Namibia, as a well known common plant in the western desert of Egypt *from the Mediterranean coas ...

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

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

s in the sandy areas.

References

{{coord, 30.255, 28.931, type:waterbody_region:EG, display=inline,title Oases of Egypt Western Desert (Egypt)