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Emi Koussi
Emi Koussi (also known as Emi Koussou) is a high pyroclastic shield volcano that lies at the southeast end of the Tibesti Mountains in the central Sahara, in the northern Borkou Region of northern Chad. The highest mountain of the Sahara, the volcano is one of several in the Tibesti range, and reaches an elevation of , rising above the surrounding sandstone plains. The volcano is wide and has a volume of . Two nested calderas cap the volcano, the outer one being about in size. Within it on the southeast side is a smaller caldera known as Era Kohor, about wide and deep. Numerous lava domes, cinder cones, maars, and lava flows are found within the calderas and along the outer flanks of the shield. Era Kohor contains trona deposits, and Emi Koussi has been studied as an analogue of the Martian volcano Elysium Mons. Emi Koussi was active more than one million years ago, but some eruptions may be more recent, and there is ongoing fumarolic and hot spring activity. Geography ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chad
Chad, officially the Republic of Chad, is a landlocked country at the crossroads of North Africa, North and Central Africa. It is bordered by Libya to Chad–Libya border, the north, Sudan to Chad–Sudan border, the east, the Central African Republic to Central African Republic–Chad border, the south, Cameroon to Cameroon–Chad border, the southwest, Nigeria to Chad–Nigeria border, the southwest (at Lake Chad), and Niger to Chad–Niger border, the west. Chad has a population of 19 million, of which 1.6 million live in the Capital city, capital and largest city of N'Djamena. With a total area of around , Chad is the fifth-largest country in Africa and the List of countries and dependencies by area, twentieth largest nation by area. Chad has several regions: the Sahara desert in the north, an arid zone in the centre known as the Sahel, and a more fertile Sudanian Savanna zone in the south. Lake Chad, after which the country is named, is the second-largest wetl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mars
Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmospheric pressure is a few thousandths of Earth's, atmospheric temperature ranges from and cosmic radiation is high. Mars retains some water, in the ground as well as thinly in the atmosphere, forming cirrus clouds, frost, larger polar regions of permafrost and ice caps (with seasonal snow), but no liquid surface water. Its surface gravity is roughly a third of Earth's or double that of the Moon. It is half as wide as Earth or twice the Moon, with a diameter of , and has a surface area the size of all the dry land of Earth. Fine dust is prevalent across the surface and the atmosphere, being picked up and spread at the low Martian gravity even by the weak wind of the tenuous atmosphere. The terrain of Mars roughly follows a north-south ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Escarpment
An escarpment is a steep slope or long cliff that forms as a result of faulting or erosion and separates two relatively level areas having different elevations. Due to the similarity, the term '' scarp'' may mistakenly be incorrectly used interchangeably with ''escarpment.'' ''Escarpment'' referring to the margin between two landforms, and ''scarp'' referring to a cliff or a steep slope. In this usage an escarpment is a ridge which has a gentle slope on one side and a steep scarp on the other side. More loosely, the term ''scarp'' also describes a zone between a coastal lowland and a continental plateau which shows a marked, abrupt change in elevation caused by coastal erosion at the base of the plateau. Formation and description Scarps are generally formed by one of two processes: either by differential erosion of sedimentary rocks, or by movement of the Earth's crust at a geologic fault. The first process is the more common type: the escarpment is a transition from one seri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shield Volcano
A shield volcano is a type of volcano named for its low profile, resembling a shield lying on the ground. It is formed by the eruption of highly fluid (low viscosity) lava, which travels farther and forms thinner flows than the more viscous lava erupted from a stratovolcano. Repeated eruptions result in the steady accumulation of broad sheets of lava, building up the shield volcano's distinctive form. Shield volcanoes are found wherever fluid, low-silica lava reaches the surface of a rocky planet. However, they are most characteristic of ocean Volcanic island, island volcanism associated with Hotspot (geology), hot spots or with Rift, continental rift volcanism. They include the largest active volcanoes on Earth, such as Mauna Loa. Giant shield volcanoes are found on other planets of the Solar System, including Olympus Mons on Mars and Sapas Mons on Venus. Etymology The term 'shield volcano' is taken from the German term ''Schildvulkan'', coined by the Austrian geologist Eduar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbit
In celestial mechanics, an orbit (also known as orbital revolution) is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as a planet, moon, asteroid, or Lagrange point. Normally, orbit refers to a regularly repeating trajectory, although it may also refer to a non-repeating trajectory. To a close approximation, planets and satellites follow elliptic orbits, with the center of mass being orbited at a focal point of the ellipse, as described by Kepler's laws of planetary motion. For most situations, orbital motion is adequately approximated by Newtonian mechanics, which explains gravity as a force obeying an inverse-square law. However, Albert Einstein's general theory of relativity, which accounts for gravity as due to curvature of spacetime, with orbits following geodesics, provides a more accurate calculation and u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Massif
A massif () is a principal mountain mass, such as a compact portion of a mountain range, containing one or more summits (e.g. France's Massif Central). In mountaineering literature, ''massif'' is frequently used to denote the main mass of an individual mountain. As a purely scientific term in geology, however, a "massif" is separately and more specifically defined as a section of a planet's crust (geology), crust that is demarcated by geologic fault, faults or lithospheric flexure, flexures. In the plate tectonics, movement of the crust, a massif tends to retain its internal structure while being displaced as a whole. A massif is a smaller structural unit than a tectonic plate and is considered the fourth-largest driving force in geomorphology. The word "massif" originates from French (in which the word also means "massive"), where it is used to refer to a large mountain mass or compact group of connected mountains forming an independent portion of a range. The Cydonia (regi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tedaga
The Teda language, also known as Tedaga, Todaga, Todga, or Tudaga is a Nilo-Saharan language spoken by the Teda, a northern subgroup of the Toubou people who inhabit southern Libya, northern Chad and eastern Niger. A small number also inhabit northeastern Nigeria Nigeria, officially the Federal Republic of Nigeria, is a country in West Africa. It is situated between the Sahel to the north and the Gulf of Guinea in the Atlantic Ocean to the south. It covers an area of . With Demographics of Nigeria, .... Along with the more populous southern dialect of Daza, the northern Teda dialect constitutes one of the two varieties of Tebu. However, Teda is also sometimes used for Tebu in general. Phonology Consonants Vowels References * * * * * * * * * Tebu languages Saharan languages Languages of Chad Languages of Niger Languages of Nigeria Languages of Libya Toubou people {{ns-lang-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toubou
The Toubou or Tubu (from Old Tebu, meaning "rock people") are an ethnic group native to the Tibesti Mountains that inhabit the central Sahara in northern Chad, southern Libya, northeastern Niger, and northwestern Sudan. They live either as herders and nomads or as farmers near oases. Their society is clan-based, with each clan having certain oases, pastures and wells. The Toubou are generally divided into two closely related groups: the Teda (or Tuda, Téda, Toda, Tira) and the Daza (or Dazzaga, Dazagara, Dazagada). They are believed to share a common origin and speak the Tebu languages, which are from the Saharan branch of the Nilo-Saharan language family. Tebu is divided further into two closely related languages, called '' Tedaga'' (Téda Toubou) and ''Dazaga'' (Daza Toubou). Of the two groups, the Daza, found to the south of the Teda, are more numerous. The Toubou people are also referred to as the Tabu, Tebu, Tebou, Tibu, 'Tibbu, Toda, Todga, Todaga, Tubu, Tuda, Tudaga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dirt Road
A dirt road or track is a type of unpaved road not paved with asphalt, concrete, brick, or stone; made from the native material of the land surface through which it passes, known to highway engineers as subgrade material. Terminology Similar terms Terms similar to dirt road are ''dry-weather road'', ''earth road'', or the "Class Four Highway" designation used in China. A ''track'', ''dirt track'', or ''earth track'' would normally be similar but less suitable for larger vehicles—the distinction is not well-defined. Laterite and murram roads, depending on material used, may be dirt roads or improved roads. Improved road Unpaved roads with a harder surface made by the addition of material such as gravel and aggregate (stones), might be referred to as dirt roads in common usage but are distinguished as improved roads by highway engineers. Improved unpaved roads include gravel roads and macadamized roads. Characteristics Compared to a gravel road, a dirt road is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dome
A dome () is an architectural element similar to the hollow upper half of a sphere. There is significant overlap with the term cupola, which may also refer to a dome or a structure on top of a dome. The precise definition of a dome has been a matter of controversy and there are a wide variety of forms and specialized terms to describe them. A dome can rest directly upon a Rotunda (architecture), rotunda wall, a Tholobate, drum, or a system of squinches or pendentives used to accommodate the transition in shape from a rectangular or square space to the round or polygonal base of the dome. The dome's apex may be closed or may be open in the form of an Oculus (architecture), oculus, which may itself be covered with a roof lantern and cupola. Domes have a long architectural lineage that extends back into prehistory. Domes were built in ancient Mesopotamia, and they have been found in Persian architecture, Persian, Ancient Greek architecture, Hellenistic, Ancient Roman architecture, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Africa
Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surface area.Sayre, April Pulley (1999), ''Africa'', Twenty-First Century Books. . With nearly billion people as of , it accounts for about of the world's human population. Demographics of Africa, Africa's population is the youngest among all the continents; the median age in 2012 was 19.7, when the worldwide median age was 30.4. Based on 2024 projections, Africa's population will exceed 3.8 billion people by 2100. Africa is the least wealthy inhabited continent per capita and second-least wealthy by total wealth, ahead of Oceania. Scholars have attributed this to different factors including Geography of Africa, geography, Climate of Africa, climate, corruption, Scramble for Africa, colonialism, the Cold War, and neocolonialism. Despite this lo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
