|
Dome (geology)
A dome is a feature in structural geology consisting of symmetrical anticlines that intersect each other at their respective apices. Intact, domes are distinct, rounded, spherical-to- ellipsoidal-shaped protrusions on the Earth's surface. However, a transect parallel to Earth's surface of a dome features concentric rings of strata. Consequently, if the top of a dome has been eroded flat, the resulting structure in plan view appears as a bullseye, with the youngest rock layers at the outside, and each ring growing progressively older moving inwards. These strata would have been horizontal at the time of deposition, then later deformed by the uplift associated with dome formation. Formation mechanisms There are many possible mechanisms responsible for the formation of domes, the foremost of which are post-impact uplift, refolding, and diapirism. Post-impact uplift A complex crater, caused by collision of a hypervelocity body with another larger than itself, is typified by th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ASTER Richat
Aster or ASTER may refer to: Biology * ''Aster'' (genus), a genus of flowering plants ** List of ''Aster'' synonyms, other genera formerly included in ''Aster'' and still called asters in English * Aster (cell biology), a cellular structure shaped like a star, formed around each centrosome during mitosis * Aster, a star-shaped sponge spicule Automobiles * Ateliers de Construction Mecanique l'Aster, a French automobile and engine manufacturer from 1900 to 1910 * Aster Società Italiana Motori, an Italian automobile manufacturer from 1906 to 1908 * Aster (automobile), a British automobile manufactured between 1922 and 1930 Military * Aster (missile family), a family of Surface to Air Missiles, produced jointly by France, Great Britain, and Italy * USS ''Aster'', a Civil War Union Navy tugboat * , two Royal Navy ships * Belgian minehunter ''Aster'' (M915), ship * Operation Aster, by the Soviet Army in 1944 in Estonia Businesses * Aster (venture capital company) * Aster Data Sy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fold (geology)
In structural geology, a fold is a stack of originally planar surfaces, such as sedimentary strata, that are bent or curved during permanent deformation. Folds in rocks vary in size from microscopic crinkles to mountain-sized folds. They occur as single isolated folds or in periodic sets (known as ''fold trains''). Synsedimentary folds are those formed during sedimentary deposition. Folds form under varied conditions of stress, pore pressure, and temperature gradient, as evidenced by their presence in soft sediments, the full spectrum of metamorphic rocks, and even as primary flow structures in some igneous rocks. A set of folds distributed on a regional scale constitutes a fold belt, a common feature of orogenic zones. Folds are commonly formed by shortening of existing layers, but may also be formed as a result of displacement on a non-planar fault (''fault bend fold''), at the tip of a propagating fault (''fault propagation fold''), by differential compaction or due to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Himachal Pradesh
Himachal Pradesh (; ; "Snow-laden Mountain Province") is a state in the northern part of India. Situated in the Western Himalayas, it is one of the thirteen mountain states and is characterized by an extreme landscape featuring several peaks and extensive river systems. Himachal Pradesh is the northernmost state of India and shares borders with the union territories of Jammu and Kashmir and Ladakh to the north, and the states of Punjab to the west, Haryana to the southwest, Uttarakhand to the southeast and a very narrow border with Uttar Pradesh to the south. The state also shares an international border to the east with the Tibet Autonomous Region in China. Himachal Pradesh is also known as , meaning 'Land of Gods' and which means 'Land of the Brave'. The predominantly mountainous region comprising the present-day Himachal Pradesh has been inhabited since pre-historic times, having witnessed multiple waves of human migrations from other areas. Through its history, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reo Purgyil
Reo Purgyil, sometimes known as Leo Pargial and Leo Pargil, is a mountain peak at the southern end of the Zanskar Range in the Western Himalaya. It is located the border between Himachal Pradesh, India and Tibet. At 6,816 m, Reo Purgyil is the highest mountain peak in the state of Himachal Pradesh and is located in Kinnaur district. Geologically the peak is a dome structure and is part of a great massif that rises above the Sutlej river and overlooks the western valleys of Tibet. The Spiti River, a right bank tributary of the Satluj, drains the northern face of the massif. The highest peak is often obscured by clouds and is located about 2 km to the south of Peak 6791, a well known slightly shorter twin with a height of 6,791 m. Peak 6791 is widely referred to as Leo Pargial and has sufficient topographic prominence to be classified as a mountain in its own right. Nako village is located on the slopes of the mountain, close to the India-Tibet border. Climbing history * 1s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mabja
This is an alphabetical list of all populated places, including cities, towns and villages, in the Tibet Autonomous Region of western China. A *Alamdo *Alhar *Arza *Asog B *Baga, Tibet, Baga *Bagar *Baidi, Nagarzê County, Baidi *Baima *Baimai *Baixoi *Bamda *Banag *Banbar *Banggaidoi *Bangkor *Bangru *Bangxing *Baqên Town, Baqên *Bar *Bêba *Bei *Bênqungdo *Bilung *Birba *Biru Town, Biru *Bogkamba *Boindoi *Bolo, Gonjo County, Bolo *Bongba *Boqê *Bumgyê *Bungona’og *Bünsum *Burang Town, Burang *Bushêngcaka C *Caina Township, Caina *Cakaxiang *Camco *Cawarong *Cazê *Cêgnê *Cêngdo *Cêri *Cêrwai *Chabug *Chacang *Chagla *Chagna *Chagyoi *Cha’gyüngoinba *Chalükong *Chamco *Chamda *Chamoling *Changgo *Changlung *Changmar *Charing *Chatang *Chawola *Chêcang *Chênggo *Chepzi *Chibma *Chido *Chigu *Chongkü *Chongsar *Chowa *Chubalung *Chubarong *Chuka *Chumba *Chumbu *Chunduixiang *Co Nyi *Cocholung *Codoi, Tibet, Codoi *Cogo, Tibet, Cogo *Coka, Tibet, Co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pilbara Craton
The Pilbara Craton is an old and stable part of the continental lithosphere located in the Pilbara region of Western Australia. The Pilbara Craton is one of only two pristine Archaean 3.6–2.7 Ga (billion years ago) crusts identified on the Earth, along with the Kaapvaal Craton in South Africa. Both locations may have once been part of the Vaalbara supercontinent or the continent of Ur. The eastern portion is called the Eastern Pilbara Craton. Evidence of earliest life In May 2017, evidence of the earliest known life on land may have been found in 3.48-billion-year-old geyserite and other related mineral deposits (often found around hot springs and geysers) uncovered in the Dresser Formation in Pilbara Craton. The earliest ''direct'' evidence of life on Earth may be fossils of microorganisms permineralized in 3.465-billion-year-old Australian Apex chert rocks. However, the evidence for the biogenicity of these microstructures has been thoroughly debated. Originally, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karatau
Karatau ( kz, Қаратау, ''Qaratau'') is an administrative center in the Talas region located in the Jambyl Region in the south of Kazakhstan. It has an estimated population of roughly 30,000 in 1999. , the population is now 27,667. The largest city from Karatau, Taraz, is approximately 100 km to the southwest. Name The name ''Karatau'' means ''Black Mountain'' in the Kazakh language. Karatau was named after the Karatau Mountain range which it is located next to and was famous during the Soviet era for phosphate. As part of the de-russification of the Kazakh language, Karatau will be re-written with Latin scripts in 2025 and spelled Qaratau. Ghost Town Krisha KZ reported on Karatau describing this town as a ghost town in December, 2019. The value of apartments in Karatau, according to Krisha, was between $3300–$11,500 USD. Economy Industry During the Soviet Union times, the main functioning industrial enterprise in the town was the phosphorite factory. Transpo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vredefort Dome
The Vredefort impact structure is the largest verified impact structure on Earth. The crater, which has since been eroded away, was around across when it was formed. The remaining structure, comprising the deformed underlying bedrock, is located in present-day Free State province of South Africa. It is named after the town of Vredefort, which is near its centre. The structure's central uplift is known as the Vredefort Dome. The impact structure was formed during the Paleoproterozoic Era, 2.023 billion years (± 4 million years) ago. It is the second-oldest known impact structure on Earth, after Yarrabubba. In 2005, the Vredefort Dome was added to the list of UNESCO World Heritage Sites for its geologic interest. Formation and structure The asteroid that hit Vredefort is estimated to have been one of the largest ever to strike Earth since the Hadean Eon some four billion years ago, originally thought to have been approximately in diameter. The bolide that created the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Upheaval Dome
Upheaval Dome is an enigmatic geological structure in San Juan County, Utah, United States, that has been variously interpreted as a meteorite impact structure or a salt dome. The structure lies southwest of the city of Moab, Utah, in the Island in the Sky section of Canyonlands National Park. Description Upheaval Dome is approximately in diameter and the crater is known to be less than 170 million years old (Jurassic or younger, but how much younger is not established.) The crater is clearly visible on the surface as light and dark brown concentric rings. Stratigraphically, the oldest formation exposed in the center of the dome is the Permian Organ Rock Shale. This is overlain by the Permian White Rim Sandstone. Both are sometimes considered part of the Cutler Formation. Overlying these are the Triassic Moenkopi Formation (which is bounded top and bottom by unconformities), the Chinle Formation, the cliff-forming Wingate Sandstone, the Kayenta Formation, and the cro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Migmatite
Migmatite is a composite rock found in medium and high-grade metamorphic environments, commonly within Precambrian cratonic blocks. It consists of two or more constituents often layered repetitively: one layer is an older metamorphic rock that was reconstituted subsequently by partial melting ("paleosome"), while the alternate layer has a pegmatitic, aplitic, granitic or generally plutonic appearance ("neosome"). Commonly, migmatites occur below deformed metamorphic rocks that represent the base of eroded mountain chains. Migmatites form under extreme temperature and pressure conditions during prograde metamorphism, when partial melting occurs in metamorphic paleosome. Components exsolved by partial melting are called neosome (meaning ‘new body’), which may or may not be heterogeneous at the microscopic to macroscopic scale. Migmatites often appear as tightly, incoherently folded veins ( ptygmatic folds).Recommendations by the IUGS Subcommission on the Systematics of M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diapir
A diapir (; , ) is a type of igneous intrusion in which a more mobile and ductily deformable material is forced into brittle overlying rocks. Depending on the tectonic environment, diapirs can range from idealized mushroom-shaped Rayleigh–Taylor-instability-type structures in regions with low tectonic stress such as in the Gulf of Mexico to narrow dikes of material that move along tectonically induced fractures in surrounding rock. The term was introduced by the Romanian geologist Ludovic Mrazek, who was the first to understand the principle of salt tectonics and plasticity. The term ''diapir'' may be applied to igneous structures, but it is more commonly applied to non-igneous, relatively cold materials, such as salt domes and mud diapirs. Occurrence Differential loading causes salt deposits covered by overburden (sediment) to rise upward toward the surface and pierce the overburden, forming diapirs (including salt domes), pillars, sheets, or other geological structu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rayleigh–Taylor Instability
The Rayleigh–Taylor instability, or RT instability (after Lord Rayleigh and G. I. Taylor), is an instability of an interface between two fluids of different densities which occurs when the lighter fluid is pushing the heavier fluid. Drazin (2002) pp. 50–51. Examples include the behavior of water suspended above oil in the gravity of Earth, mushroom clouds like those from volcanic eruptions and atmospheric nuclear explosions, supernova explosions in which expanding core gas is accelerated into denser shell gas, instabilities in plasma fusion reactors and inertial confinement fusion. Water suspended atop oil is an everyday example of Rayleigh–Taylor instability, and it may be modeled by two completely plane-parallel layers of immiscible fluid, the denser fluid on top of the less dense one and both subject to the Earth's gravity. The equilibrium here is unstable to any perturbations or disturbances of the interface: if a parcel of heavier fluid is displaced downward with a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
