Wadi El-Natrun rocks are not well exposed and relatively show lack in fossils. Various lithostratigraphic units forms the surface of Wadi El-Natrun and its aquifer systems. The bottom of Wadi El-Natrun is occupied by eleven saline lakes, representing a discharge area. The flow of groundwater is observed from both the east (Nile Delta) and the west (Western Desert) towards the depression (Attia et al., 2007 and RIGW, 1992). Localized flow fields has been developed due to the excessive pumping of groundwater used for irrigation (El-Sheikh, 2000 and Masoud and Atwia, 2010). Wadi El-Natrun is covered by lake deposits and old alluvial deposits of sand and gravel deposited during sea encroachment and the Nile intersect it (Philip et al., 1975). They belong to Quaternary Period. Wadi El-Natrun area is dominated by a sedimentary section which is represented by the oldest Triassic Age to the youngest Pliocene Age with thickness greater than 4 km.
The area west of Nile Delta is distinguished by its mild topography and low relief. It is represented by the Quaternary and Neogene deposits. Quaternary deposits belong to Pleistocene and Recent whereas Neogene deposits are Miocene (subsurface) in age (Said, 1961; Said, 1993).
Wadi El-Natrun is is basically composed of shallow marine, brackish water deposits, and clayey facies at the base and fluviomarine and shallow marine deposits at the top. Pliocene deposits reach up to 150 m. In general, Wadi El-Natrun is covered by sedimentary succession of Oligocene, Miocene, Pliocene and Pleistocene epoch. Oligocene rocks outcrop in area of southwest corner of Nile Delta. Miocene and Pliocene are generally distributed in west and south of Wadi El-Natrun whereas Quaternary sediments dominate towards north.
The surface of Wadi El-Natrun is mainly covered by Pleistocene sands and gravels in addition to, sabkhas and salty crusts along the scattered lakes along its axis. The surface is underlain by Pliocene epoch which is represented by sands, clays, sandy clays, and limestone intercalations and is unconformably underlain by 150 m thick early Miocene rocks (El Hinnawi and Atwa, 1973).
Blanckenhorn (1921) assigned a Late Pliocene age to the beds exposed in Wadi El- Natrun depression. Ball (1939) described the Pliocene rocks of Wadi El-Natrun as of a fluviatile or estuarine origin. These rocks consist of sand and gypseous clay, containing remains of elephants, giraffs and other land animals together with crocodiles and fish. Sandford and Arkell (1939) assigned Plio-Pleistocene to Early Pleistocene times to the gravel terraces of the west Nile Delta.
Shata (1955) has recognized two series belong to the Pliocene in Wadi El-Natrun area. The upper series is composed of porcellaneous limestone with flint, while the lower series is composed of thick shale beds alternating with argillaceous sandstone. The exposed Pliocene rocks at Wadi El-Natrun are divided into the Mikheimin formation (Lower Pliocene) and the Muluk formation (Upper Pliocene) (Abu Zeid, 1984).
The subsurface thickness of sedimentary marine and continental rocks overlying the basement reaches up to (4000 m) (Figure 2.1) according to oil drilling test well No.1 (Phillips, 1970).
Figure 2.1: Lithostratigraphic section of Wadi El-Natrun (Philips, 1970).
Depth
(m) Age Stage Log Lithological Description
Loose quartz sand & green pyritic clay Loose coarse sand with lenses of dark clay
Basalt
Sticky grey clay with occassionally lenses of of quartz sand
Clay and shale, grey stiky dolomitic to very calcareous
Sand
Argiliaceous and chalky limestone with thin bands of chalk
Limestone, greyish green Dolomite
Dolomitic shale and limestone sandy at base
Loose sands with thin lenses of shale
Limestone, grey fine grained microcrystalline oolitic and detrital inclosion
Alternating fine grained limestone and shale with carbonaceous material and coal
Sand and limestone strings grads into argilleous limestone
Basement 100
200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 2400 2500 2600 2700 2800 2900 3000 3100 3200 3300 3400 3500 3600 3700 3800 3900 4000
Plio. Mio.
OligoceneEocene Upper EoceneM. Eo.Lower Eocene
Cretaceous
U.
Cr.
TuronianCenomanianLower Cretaceous
Jurassic MalmDogger
Triassic
Fig. (3-2): Wadi El Natrun Test Well No. 1 (Compiled after Phillips, 1970)
232 1152 567 840 533 390 190 130
Thick.
Loose quartz sand and green pyritic clay
Lithostartigraphic Descritption
Loose coarse sand with lenses of dark clay
Sticky grey clay with occasionally lenses of quartz sand
Grey sticky dolomitic to very calcareous clay and shale
Argillaceous and chalky limestone with thin bands of chalk
Greyish green limestone Sand
Basalt Basalt
Sand
Dolomite
Grey oolitic limestone
Dolomite shale and sandy limestone at base
Loose sand with thin shale lenses
Alternating fine grained limestone and shale with coal
Basement
Sand and limestone strings grads into argillaceous limestone
The oldest exposed rocks in Wadi El-Natrun area is Miocene rocks, occupying most of the area to south of the wadi (depression) whereas within Wadi El-Natrun depression the surface exposures are dominated by Pliocene shallow marine and continental formations and post Pliocene fluvio-marine deposits. The study of Wadi El-Natrun exposed rocks in addition to drilled wells (surface and subsurface) Shata (1962) divided rocks into three units from exploratory core base 200 m of Miocene shallow marine lacustrine deposits composed of coarse and fine-grained sand followed by Pliocene strata measuring around (200 m) and are divided into two units. Upper calcareous grit and impervious clay whereas the lower unit is dominated by green clays. These two rock units are topped by widely distributed Quaternary and Recent strata. The Quaternary rocks are differentiated into Pleistocene and Recent. Recent rocks are represented from top to base by windblown sands and downwash deposits and silt deposits of the Nile Delta (25 m).
Tertiary rocks are represented by (Oligocene, Miocene and Pliocene) rocks (Abu Zeid, 1984).
The Triassic succession is made up of shale and limestone intercalations whereas the Jurassic strata are mainly composed of limestone and shale with sandstone lenses. The Cretaceous rocks unconformably underlie the Eocene deposits. Cretaceous rocks are divided into lower and upper Cretaceous rocks. The Upper Cretaceous strata are mainly represented by carbonate rocks with shaly facies whereas the Lower Cretaceous strata are dominated by sandy rocks intercalated with clay and cemented by calcite. The Eocene rocks are made up of limestone at the base and topped by clay and shale (El Shazly et al., 1975). Pliocene rocks are differentiated into Wadi El-Natrun Formation (70 m) of brackish water deposits and Lower El Mekhimien Formation (100 m) marine deposits.
The Miocene El Raml Formation (200 m) is represented by poorly fossiliferous deltaic sand and sandstone (Abou-Khadrah, 1973). Said (1962) assigned fluvio-marine environments for Lower Miocene Moghra formation. Sanad (1973) and Omara and Sanad (1975) classified the area
lying between Wadi El-Natrun and El Moghra depression into: Early Miocene (El Moghra Formation), Early Pliocene Formation (Wadi El-Natrun Formation), Late Pliocene (El Hagif Formation), Early Pleistocene include old gravel and Late Pleistocene-Recent represented by young gravel, loam deposits, sand dune chains and sand dunes (Omara and Sanad, 1975).
BIBLIOGRAPHY
Abdel Baki, A. M. A. (1983). Hydrogeological and hydrogeochemical studies in the area west of Rosetta branch and south El Nasr canal, Ph. D. Thesis, Fac. Sci., Ain Shams University, 156 p Abu Khadrah, A. (1973). Geological and sedimentological studies of Wadi E1-Natrun district,
Western Desert, Egypt. Ph. D. Thesis, Fac. Sci., Cairo University
Abu Zeid, K.A. (1984). Contribution to the geology of Wadi El-Natrun area and its surroundings.
M.Sc. Thesis, Fac. Sci., Cairo University
Attia, F.A.R., Fahmy, H., Eid, M. and Slootweg, R. (eds.) (2007). The west Delta water conservation, irrigation rehabilitation project (WDWCIRP) environmental and social impacts, and a framework management-plan part 1: Environmental and social impact assessment, part 2: environmental and social management plan-final draft. Arab Republic of Egypt Ministry of Water Resources and Irrigation and World Bank
Attia, S. H. (1975). Pedology and soil genesis of the Quaternary deposits in the region west of the Nile Delta (north and east of Wadi El-Natrun) Ph. D. Thesis, Fac. Sci., Ain Shams University, Cairo, Egypt, 288 p
Ball, J. (1939). Contributions to the geography of Egypt. Egypt Survey and Mines Dept. Cairo:
1-105
Blankenhorn, M. (1921). Handbuch der regionalen Geologie Aegypten”. Bd. Abt. 9, Hebt 23, Aegypten. Heidelberg, 2, 244 p
El Shazly, E.M. Abdel Hady, M. A., El Ghawaby, M.A., El Kassas, I.A., El Khawasik, S.M., El Shazly, M.M., and Sanad, S. (1975). Geological interpretation of Landsat. images for west Nile Delta area, Egypt. Remote sensing Research Project, Academic of Scientific Research and Technology, Egypt
El-Fayoumy, I.F. (1964). Geology of groundwater supplies in Wadi El-Natrun area. M.Sc., Thesis, Fac. Sci., Cairo University, Egypt, 200 p
El-Hinnawi, E. E. and Atwa, S. M. (1973). Geochemistry of ground waters from some localities west of the Nile Delta. Geologische Rundschau, 62: 225-245
El-Shahat, A., Ayyad, S. N. and Abdalla, M. A. (1997). Pliocene Facies and Fossil Contents of Qaret El-Muluk Formation at Wadi El-Natrun Depression, Western Desert, Egypt
El-Sheikh, A. (2000): Hydrogeology of the area north and west of Wadi El Natrun, Fac. Sci., Menoufia University, Egypt, 151 p
General Petroleum Company “GPC” (1977). The groundwater resources of Wadi El-Natrun area, Western Desert, Egypt. Internal report, Cairo, Egypt, 82 p
Omara, S. and Sanad, S. (1975). Rock stratigraphy and structural features of the area between Wadi El-Natrun and the Moghra Depression (Western Desert, Egypt). Geol. Jb., 16: 45-73 Phillip, G; Barakat, M. G.; Abu Khadrah, A. (1975). Stratigraphy and mechanical analysis of
Neogene sediments in Wadi El Natrun area, Egypt. Fac. Sci., Cairo University, Bull. No. 48 Phillips Petroleum Company (1970). “Geological report of Tiba well-1, Western Desert Egypt”.
Internal report, 15 p
RIGW (1992). Groundwater resources and projection of groundwater development, water security project. National Water Research Center, Egypt, 37 p
Said, R. (1962). The geology of Egypt. Elsevier, Amsterdam, 377 p
Said, R. (1990). The geology of Egypt. (ed. By Said, R.) A. A. Balkema/Rotterdam/Brookfiled, 722 p
Said, R. (1993). The Nile River: Geology, Hydrology, and Utilization. Pergamon, New York, USA Sanad, S. (1973). Geology of the area between Wadi El-Natrun and the Moghra depression. Ph.D.
Thesis, Fac. Sci. Assuit University, Assuit, Egypt, 184 p
Sandford, K.S. and Arkell, W.J. (1939). Paleolithic man and the Nile Valley in Lower Egypt.
Chicago University, Oriental Inst. Publ., 36: 1-105
Shata, A. A. (1953). New light on structural development of the Western Desert of Egypt. Bull.
Inst. Desert d'Egypt, T. 3, No. l: 101-106
Shata, A. A. (1955). An introduction note on the geology of the northern portion of the Western Desert of Egypt. Bull. Inst. Desert, Egypt, 5, No.3
Shata, A. A. and El Fayoumy, I. F. (1970). Remarks on the hydrogeology of the Nile Delta.
Proceedings of the Bucharest Symposium on Delta 6-14 May 1969
Shata, A.A. (1962). Geology, In: Preliminary report on the geology, hydrology and groundwater hydrology of Wadi El-Natrun and adjacent areas. Part. 1, Desert Inst., Cairo, U.A.R., 39 p