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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 Nubian Sandstone was deposited between the Lower Paleozoic and Upper Cretaceous, with marine beds dating from the Carboniferous to Lower Cretaceous. Formation The Nubian Sandstone ranges in age from the Cambrian to Upper Cretaceous eras. Positioning of the paleoequator and paleolatitude at 20° S was derived from paleomagnetic data showing the Nubian was originally deposited in the paleoequatorial to subequatorial zone. These paleomagnetic results corroborated previous studies suggesting that north Africa did not shift in latitude from 210 to 110 million years ago and extended this period to 85 million years. Nubian Sandstone was deposited under a tropical to subtropical climate and formed under a variety of continental conditions, incl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sedimentary Rock
Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles to settle in place. The particles that form a sedimentary rock are called sediment, and may be composed of geological detritus (minerals) or biological detritus (organic matter). The geological detritus originated from weathering and erosion of existing rocks, or from the solidification of molten lava blobs erupted by volcanoes. The geological detritus is transported to the place of deposition by water, wind, ice or mass movement, which are called agents of denudation. Biological detritus was formed by bodies and parts (mainly shells) of dead aquatic organisms, as well as their fecal mass, suspended in water and slowly piling up on the floor of water bodies (marine snow). Sedimentation may also occur as dissolved minerals precipitate from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aeolian Processes
Aeolian processes, also spelled eolian, pertain to wind activity in the study of geology and weather and specifically to the wind's ability to shape the surface of the Earth (or other planets). Winds may erode, transport, and deposit materials and are effective agents in regions with sparse vegetation, a lack of soil moisture and a large supply of unconsolidated sediments. Although water is a much more powerful eroding force than wind, aeolian processes are important in arid environments such as deserts. The term is derived from the name of the Greek god Aeolus, the keeper of the winds. Definition and setting ''Aeolian processes'' are those processes of erosion, transport, and deposition of sediments that are caused by wind at or near the surface of the earth. Sediment deposits produced by the action of wind and the sedimentary structures characteristic of these deposits are also described as ''aeolian''. Aeolian processes are most important in areas where there is little or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karst
Karst is a topography formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum. It is characterized by underground drainage systems with sinkholes and caves. It has also been documented for more weathering-resistant rocks, such as quartzite, given the right conditions. Subterranean drainage may limit surface water, with few to no rivers or lakes. However, in regions where the dissolved bedrock is covered (perhaps by debris) or confined by one or more superimposed non-soluble rock strata, distinctive karst features may occur only at subsurface levels and can be totally missing above ground. The study of ''paleokarst'' (buried karst in the stratigraphic column) is important in petroleum geology because as much as 50% of the world's hydrocarbon reserves are hosted in carbonate rock, and much of this is found in porous karst systems. Etymology The English word ''karst'' was borrowed from German in the late 19th century, which entered German much earlier ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbonate Rock
Carbonate rocks are a class of sedimentary rocks composed primarily of carbonate minerals. The two major types are limestone, which is composed of calcite or aragonite (different crystal forms of CaCO3), and dolomite rock (also known as dolostone), which is composed of mineral dolomite (CaMg(CO3)2). Calcite can be either dissolved by groundwater or precipitated by groundwater, depending on several factors including the water temperature, pH, and dissolved ion concentrations. Calcite exhibits an unusual characteristic called retrograde solubility in which it becomes less soluble in water as the temperature increases. When conditions are right for precipitation, calcite forms mineral coatings that cement the existing rock grains together or it can fill fractures. Karst topography and caves develop in carbonate rocks because of their solubility in dilute acidic groundwater. Cooling groundwater or mixing of different groundwaters will also create conditions suitable for cave ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quaternary
The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ago to the present. The Quaternary Period is divided into two epochs: the Pleistocene (2.58 million years ago to 11.7 thousand years ago) and the Holocene (11.7 thousand years ago to today, although a third epoch, the Anthropocene, has been proposed but is not yet officially recognised by the ICS). The Quaternary Period is typically defined by the cyclic growth and decay of continental ice sheets related to the Milankovitch cycles and the associated climate and environmental changes that they caused. Research history In 1759 Giovanni Arduino proposed that the geological strata of northern Italy could be divided into four successive formations or "orders" ( it, quattro ordini). The term "quaternary" was introduced by Jules Desnoye ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pluvial
In geology and climatology, a pluvial is either a modern climate characterized by relatively high precipitation or an interval of time of variable length, decades to thousands of years, during which a climate is characterized by relatively high precipitation or humidity, Subdivisions of a pluvial, which are characterized by relatively high precipitation, are known as a subpluvials. Formally, pluvials were equated with glacial stages of the Quaternary. However, pluvials, as in equatorial regions, can also occur during interglacial stages. Lower latitudes have even experienced major pluvials in early to mid-Holocene times. In geomorphology, a pluvial refers to a geologic episode, change, process, deposit, or feature that is the result of the action or effects of rain. Sometimes, it also refers to the fluvial action of rainwater flowing in a stream channel, including a flood, known as a pluvial flood, that is the direct result of excessive precipitation.Bradley, R.S. (2015) ''Paleoc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artesian Aquifer
An artesian aquifer is a confined aquifer containing groundwater under positive pressure. An artesian aquifer has trapped water, surrounded by layers of impermeable rock or clay, which apply positive pressure to the water contained within the aquifer. If a well were to be sunk into an artesian aquifer, water in the well-pipe would rise to a height corresponding to the point where hydrostatic equilibrium is reached. A well drilled into such an aquifer is called an ''artesian well''. If water reaches the ground surface under the natural pressure of the aquifer, the well is termed a ''flowing artesian well''. Fossil water aquifers can also be artesian if they are under sufficient pressure from the surrounding rocks, similar to how many newly tapped oil wells are pressurized. From the previous statement, it can be inferred that not all aquifers are artesian (i.e., water table aquifers occur where the groundwater level at the top of the aquifer is at equilibrium with atmospher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sudan
Sudan ( or ; ar, السودان, as-Sūdān, officially the Republic of the Sudan ( ar, جمهورية السودان, link=no, Jumhūriyyat as-Sūdān), is a country in Northeast Africa. It shares borders with the Central African Republic to the southwest, Chad to the west, Egypt to the north, Eritrea to the northeast, Ethiopia to the southeast, Libya to the northwest, South Sudan to the south and the Red Sea. It has a population of 45.70 million people as of 2022 and occupies 1,886,068 square kilometres (728,215 square miles), making it Africa's List of African countries by area, third-largest country by area, and the third-largest by area in the Arab League. It was the largest country by area in Africa and the Arab League until the 2011 South Sudanese independence referendum, secession of South Sudan in 2011, since which both titles have been held by Algeria. Its Capital city, capital is Khartoum and its most populated city is Omdurman (part of the metropolitan area of Khar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Libya
Libya (; ar, ليبيا, Lībiyā), officially the State of Libya ( ar, دولة ليبيا, Dawlat Lībiyā), is a country in the Maghreb region in North Africa. It is bordered by the Mediterranean Sea to the north, Egypt to Egypt–Libya border, the east, Sudan to Libya–Sudan border, the southeast, Chad to Chad–Libya border, the south, Niger to Libya–Niger border, the southwest, Algeria to Algeria–Libya border, the west, and Tunisia to Libya–Tunisia border, the northwest. Libya is made of three historical regions: Tripolitania, Fezzan, and Cyrenaica. With an area of almost 700,000 square miles (1.8 million km2), it is the fourth-largest country in Africa and the Arab world, and the List of countries and outlying territories by total area, 16th-largest in the world. Libya has the List of countries by proven oil reserves, 10th-largest proven oil reserves in the world. The largest city and capital, Tripoli, Libya, Tripoli, is located in western Libya and contains over ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sinai Peninsula
The Sinai Peninsula, or simply Sinai (now usually ) (, , cop, Ⲥⲓⲛⲁ), is a peninsula in Egypt, and the only part of the country located in Asia. It is between the Mediterranean Sea to the north and the Red Sea to the south, and is a land bridge between Asia and Africa. Sinai has a land area of about (6 percent of Egypt's total area) and a population of approximately 600,000 people. Administratively, the vast majority of the area of the Sinai Peninsula is divided into two Governorates of Egypt, governorates: the South Sinai Governorate and the North Sinai Governorate. Three other governorates span the Suez Canal, crossing into African Egypt: Suez Governorate on the southern end of the Suez Canal, Ismailia Governorate in the center, and Port Said Governorate in the north. In the classical era the region was known as Arabia Petraea. The peninsula acquired the name Sinai in modern times due to the assumption that a mountain near Saint Catherine's Monastery is the Biblical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gulf Of Suez
The Gulf of Suez ( ar, خليج السويس, khalīǧ as-suwais; formerly , ', "Sea of Calm") is a gulf at the northern end of the Red Sea, to the west of the Sinai Peninsula. Situated to the east of the Sinai Peninsula is the smaller Gulf of Aqaba. The gulf was formed within a relatively young but now inactive Gulf of Suez Rift rift basin, dating back about 26 million years. It stretches some north by northwest, terminating at the Egyptian city of Suez and the entrance to the Suez Canal. Along the mid-line of the gulf is the boundary between Africa and Asia. The entrance of the gulf lies atop the mature Gemsa oil and gas field. The gulf is considered one of the world's important maritime zones due to being an entrance to the Suez Canal. Geography The gulf occupies the northwestern arm of the Red Sea between Africa and the Sinai Peninsula. It is the third arm of the triple junction rift system, the second arm being the Gulf of Aqaba. The length of the gulf, from its mouth at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bahariya
El-Wahat el-Bahariya or el-Bahariya ( ar, الواحات البحرية "''El-Wāḥāt El-Baḥrīya''", "the Northern Oases"); is a depression and a naturally rich oasis in the Western Desert of Egypt. It is approximately 370 km away from Cairo. The roughly oval valley extends from northeast to southwest, has a length of 94 km, a maximum width of 42 km and covers an area of about 2000 km². The valley is surrounded by mountains and has numerous springs. Located in Giza Governorate, the main economic sectors are agriculture, iron ore mining, and tourism. The main agricultural products are guavas, mangos, dates, and olives. Etymology The Western Oasis was known as ''Diwah Ēmbemdje'', "Oasis of Bemdje", Old Coptic: ⲧⲁⲥⲧ(ⲥ), from Egyptian ''ḏsḏs''. Towns Bahariya consists of many villages, of which El Bawiti is the largest and the administrative center. Qasr is el-Bawiti's neighboring/twin village. To the east, about ten kilometers away are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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