Lakhasly

.1.1. West Al-Zaiat area
West El Zaiat area is located at Latitude: 25˚21’21.163’’N and longitude: 29˚27’10.058’’E In the West El Zaiat area, there are two distinct units in the geological formation: The first unit is Lower Unit; This unit comprises lenses of shale and claystone containing minerals such as glauconite, iron, limonite, and gypsum. These minerals suggest a mix of marine and terrestrial influences in the environment of deposition. The second unit is the Upper Unit; The upper unit is predominantly made up of cross-bedded sandstone with a significant thickness of cross-bedded layers. The environment in which this unit formed is interpreted as a semi-continental, very shallow marine, or fluvial setting. The presence of cross bedding in the sandstone layers indicates current activity and potentially a high-energy environment of deposition. The coarse grains observed in the sandstone further support the interpretation of high-energy deposition processes. Cross bedding, as observed in the upper unit, can be generated by various processes such as water currents, wind (contributing to the formation of sand dunes or barkhans), or wave action. In this case, the presence of cross bedding in the sandstone layers of the upper unit in the West El Zaiat area points towards a dynamic environment with active sediment transport and deposition, likely influenced by currents, winds, or waves
.1.2. Qarn Jinnah (Dakhla basin)
Qarn Jinnah is located Between El Kharga and Paris road at Latitude: 25˚ 22’ 43.381”N and Longitude 30˚ 33’ 23.201”E. Qarn Jinnah Lithology is Nubian sandstone that consists of 5 units: Tarif (fluvial sandstone), Maghrabi

2.1.4. Duwi Formation
Balat – Manfalaut road (Darb El-Taweel Road ) at Latitude: 25.623˚ N and Longitude: 29.390˚ E. Quseir formation (forms the floor of Dakhla area), The largest thickness of the Quseir variegated shale is in the Dakhla region , which is divided into two members: The first member is Lower unite (mot member) “red color”, Environment consists of continental, and Fluvial deposits (lower fluvial member). The second member is Upper unite (Hendawy member) “ green color”. glauconite and some layers of phosphate exist in the upper part of layers. The environment consists of marine deposits. The beginning of scarp is Duwi formation, Lithology: black shale at the base then phosphate (shale intercalated with hard Phosphate). Duwi formation is characterized by black shale (oil). The thickness of the Duwi formation is less than where in the Abu Tartur plateau . Also, the phosphate layers are less thick than those found in Abu Tartur, Phosphate layers are characterized by; granular in size, ranges from 0.5 m to 1 m, vertebrae remains as well as marl or black shale layers. The environment consists of shallow marine deposits. There is a sharp contact between Duwi And Dakhla. Duwi formation age is upper Cretaceous ( Campanian _ Masstrichtian
2.2. Tertiary
2.2.1. Paleocene
2.2.1.1. Dakhla shale
Kharafesh plateau at Dakhla basin at Latitude: 25˚ 37’56.5’’N, Longitude : 29˚ 26’ 30.6’’ E. The Dakhla Shale is characterized by a very thick thickness of shale, reaching up to approximately 240 meters. The Kurkur Formation overlies the Dakhla Shale Formation Dakhla shale has a sharp contact with kurkur formation, Dakhla shale formation is classified into three units; The first unit is Upper member (Paleocene), The second unit is Middle member ( markered with Ostrea Overwegi – Upper Cretaceous), The third unit is Lower member (black shale, dark gray shale, and red shale – Maastrichtian). The Upper member of the Dakhla Shale, known as Kharga member, is further divided into two members: an Upper member (Paleocene) and a Lower member (Upper Cretaceous). The significant contact between these two members is referred to as the K/T boundary, marking a distinct geological transition. The middle part of the Dakhla Shale is identified as a marker bed due to the presence of Ostrea Overwegi, indicating the end of the Cretaceous period. The Lower member of the Dakhla Shale is characterized by a very thick thickness of shale(~90m) composed of black shale, dark gray shale, and red shale, with an age dating back to the Upper Cretaceous (Maastrichtian). The Dakhla Basin is noted for its large thickness of Dakhla Shale, which is described as open marine shale that serves as a potential source of oil. The Fossils content of Dakhla shale consist of; oyster, Rich with shark teeth ,Fossils (index to the paleo Marine environment). This is a typical section to Dakhla shale.
2.2.1.2. Gabel Tarawan
Located north of El-kharga town at Latitude 25 299.26 N and Longitude 30 3339.27 E .Meanly composed from Tarawan formation, Dakhla formation . Gabel Tarawan stratigraphic consist of Tarawan formation; it`s Paleocene sediments, shallow marine environment, consist of carbonates limestone rocks. It meanly consist of two units, The first unit is Argillaceous limestone (greenish grey limestone),around 7-8 m in thickness. The second unit is pure limestone ,around 100 m in thickness. Tarawan Formation is known as a fossiliferous formation, with two zone; The first zone is Dwarf funa, The second zone is Echinocorys. Fossils like (Gastropoda ,Bivalvia ,Echinodermata ,Echinolamps, Echinochorys ovata)

Dakhla shale formation: It's dark, greenish shale with thin layer of gypsum, contains of Osteria overwegi fossil which belongs to upper Maastrichtian (here there are K/T boundary). Dakhla shale stracture, Passing by Gabal Tarawan ,some evidence was observed(which we will refer to later), which express the presence of a huge normal fault with a N-S direction. This fault exists between Taref and upper Dakhla.
2.2.1.3. Kilo 175 towards Assiut
Kilo 175 is located at Latitude: 25˚ 37’ 3.5263’’N, Longitude: 30˚ 39’6.5022”E. the thickness of Tarawan formation in Gabel Tarawan was ~ 90 m but its thickness in this area was 2:3 m ,This is an indication that the center of the basin was at Gabel Tarawan, and by moving away from it we reach the edges of the basin. Tufa is found on the scarp or on plateau , we had an example of it on the scarp. Tufa is a fresh water limestone. There are channels in the tufa that express the presence of creatures that used to live in it, such as crabs. These are considered as trace fossils that indicate that the ancient environment in which they lived was a shallow marine environment. There are also Y-shaped channels in which crabs lived. The lateral succession of layers indicating the presence of geological structures such as faults is significant. The Esna Shale serves as a marker bed that can provide information about the type of faults present in the area. By following the Esna Shale, it has been determined that natural faults are prevalent in the region. The fault direction is noted as being Northeast to Southwest NE – SW. Observations show that the layers were inclined on the scarp in an eastward direction. Additionally, a major normal fault with a North to South (N-S) direction has been identified, This fault runs parallel to the Tarawan – Dakhla fault, suggesting a significant tectonic activity in the region. The layers were inclined to each other and also to the fault, forming fault drag. When the hugging wall is inclined to the fault, forming a monocline fold.
2.2.1.4. Kurkur formation
Karstification phenomenon formation is formed by the presence of acidic rainfall , carbonate rock such as highly fracture limestone, and groundwater level. The process of karst formation typically begins with rainwater absorbing carbon dioxide from the atmosphere and soil, creating a weak carbonic acid. This mildly acidic water then percolates through the soil and limestone (which contains calcite) dissolving the mineral and widening fractures within the rock. The dissolution of calcite by carbonic acid is a key process in the development of karst topography, and it is what creates the characteristic features of karst landscapes such as underground caves and sinkholes. The karst feature occurs at the water table due to the presence of a continuous supply of carbon dioxide. the level of the water table can influence the formation of speleothems in caves and karst landscapes. When there is continuous presence of acid rain, the acidity of the water can affect the dissolution and deposition of minerals in caves, leading to the formation of these structures. Speleothems, such as stalactites and stalagmites, are formed when mineral-rich water flows through caves, depositing the minerals as it moves.
The water table plays a role in this process as it determines the level at which water can percolate through the rock and flow into the cave system. These speleothems are a result of the slow and continuous deposition of minerals over long periods of time. The presence of coarse-grained or recrystalline limestone indicates that there was enough space for the grains to grow in size. This can happen when there is enough space within the rock for the individual mineral grains to grow and rearrange themselves. This typically occurs when the original sedimentary grains are subjected to high temperatures and pressures, allowing them to recrystallize and form larger grains. The sources of carbon dioxide are Atmospheric air, Biological source (vegetation cover ), Deep reducing environment that reduces sulfate and nitrogen and produces carbon dioxide. Marine environment deposits: Fresh limestone “deep marine “ , Meteoric water environment deposits: Tufa , travertine ,playa , recrystalline limestone , speleothems. Tufa and travertine are both types of limestone rock formations that are formed by the precipitation of calcium carbonate, often associated with water bodies such as hot springs, rivers, and lakes. While they share some similarities, there are distinct differences between tufa and travertine: Tufa: Formation: Tufa is formed by the precipitation of calcium carbonate from ambient temperature water bodies, such as freshwater springs, streams, and lakes. Texture: Tufa is typically porous and spongy in texture, with a coarser and more porous structure compared to travertine. Conditions: Tufa formation is often associated with carbonate-rich groundwater that emerges at the surface, leading to the development of tufa mounds and deposits. Travertine: Formation: Travertine is formed by the precipitation of calcium carbonate from hot springs or geothermally heated water bodies.
The high temperatures and circulation of mineral-laden water play a key role in travertine formation. Texture: Travertine is known for its compact and dense nature, with finer crystalline structures and a smoother appearance compared to tufa. Conditions: Travertine formation is often associated with geothermal regions where the interaction of heated mineral-rich water with the atmosphere leads to the deposition of travertine coatings and terraces. In summary, tufa is formed from ambient-temperature water bodies and has a porous, spongy texture, while travertine is formed from hot springs or geothermally heated water and has a denser, compact texture
2.2.1.5. Naqb Assuit
Naqb Assiut area features a visible scarp where two rock units are exposed. These units are identified as Lower Eocene (Thebes), and Paleocene – Lower Eocene (Esna Shale). The contact between these two units is identified as Paleocene – Eocene. In Naqb Assiut area, the contact between the Esna Shale and Thebes is characterized by an irregular surface that is gravel and contains phosphate deposits. The Esna Shale is described as calcareous shale. Below the Esna Shale, there are spring deposits known as tufa, and underneath that layer lies the Tarawan formation. In Naqb Assiut, the rock unit composition can consist of shale, marl, or limestone due to the peculiar paleotopography of the area. The presence of limestone in the base of Naqb Assiut contrasts with the deeper Qarara basin, suggesting variations in rock composition within sub-basins. The unique composition of Naqb Assiut includes calcareous shale, which can transition to marl under certain conditions. In other neighboring areas such as Qarrara and Ain Dala in Farafra, the rock composition may consist of marl or chalk. There are two types of carbonate rocks in the region – marine carbonate represented by Eocene limestone (Thebes formation) and freshwater carbonate represented by tufa deposits. Tufa deposits form as a result of fluctuations in the groundwater table during heavy rainfall or wet climate periods. Groundwater interacts with bacteria, tree leaves, and other organisms in ponds or swamps, leading to the dissolution of limestone in water saturated with carbonates. The high-pressure, carbonate-oversaturated water precipitates tufa deposits in various shapes when it exits through fractures and joints in the rock layer.
Esna Formation:
Esna shale is a calcareous shale means that it contains a high percentage of CaCO₃ because it is an open marine environment and contains a large percentage of oxygen even if it have an organic matter , all of them will be oxidized, but Dakhla is not oxidized because it is formed in a reducing environment And the organic matter is preserved, not oxidized . Esna shale is a papery shale, its color could be : Light gray shale. Creamy with light brownish color. Greenish gray shale. These colors are different from the color of the Dakhla shale. shale intercalated with thick bands of marl and limestone near the top. between the Tarawan Formation and the Thebes Formation. A change in facies from shale/marl to carbonate is observed in the eastern part of the area under consideration where the term Gara Formation. This place is considered as one of the best places for the presence of the Esna Shale, and there are layers of carbonates within the layers of shale, these layers will form a new formation on the top of Esna shale which is called Thebes or Kurkur, Garra, This is due to their constant presence with each other , presence of limestone layers in the Esna shale and then form a complete formation of Thebes limestone , this is actually what we called gradual change Esna shale is surrounded by “ wash “ which is a fragments from the uppermost rocks ( younger rocks of Thebes ) , falling by the action of mass wasting forming sediments called “ wadi deposits .“. There are some fossils such as fossiliferous at the upper part, and there are Ecynolambs, Esters, Ecynoids at lower Eocene.
. Eocene
2.2.2.1. Thebes Formation
Karst Thebes Is a topography formed from the dissolution of soluble Rock such as Limestone. Dolomite and gypsum. Karst landscapes are characterized by number of features, including springs, sinkholes, caves, poljes. They are important FOR a variety of reasons, including; water resources of water for drinking, irrigation, and industrial use. Minerals karst landscapes are often home to valuable mineral deposits, such as lead, zinc, and copper. Most petroleum is produced from the karst. The iron ore of Bahariya and manganese ore of um Bogma formed by karstification. Lat: 24.977 N. Long: 31.091 E. Age Lower Eocene. Composition: snow white chalky limestone with chert. Environment: open marine to shallow marine. The primary reaction sequence in limestone dissolution is the following: H2O + CO2 → H2CO3 CaCO3 + H2CO3 → Ca2+ + 2HCO−3N. Conditions for karst formation. The Rock is soluble in mature Rain water, The presence of water inside Rocks for a period of time. Exist condous that receives and drops it into the rock, Exist supply and continuous supply for loud carbon dioxide, Exist plants or savana to increase the amount of CO2. So that During Quaternary age, Egypt was arid, but it also experienced significant rainfall. And Egypt full off savana. And there are carbon dioxide that came from the atmosphere during this period therefor the formation of karst in this period is very much. Karst formation occurs at the water table because the water table is receiving rainwater.