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32-474: A cinder cone (or scoria cone ) is a steep conical hill of loose pyroclastic fragments, such as volcanic clinkers, volcanic ash, or scoria that has been built around a volcanic vent . The pyroclastic fragments are formed by explosive eruptions or lava fountains from a single, typically cylindrical, vent. As the gas-charged lava is blown violently into the air, it breaks into small fragments that solidify and fall as either cinders, clinkers, or scoria around

64-413: A shield volcano , Pavonis Mons has an extremely low profile with flank slopes that average only 4°. The summit contains a deep, circular caldera that is 47 km in diameter and almost 5 km deep. A larger, shallower depression lies immediately northeast of the smaller caldera. The large depression is about 90 km in diameter and structurally more complex than the small caldera. Like most of

96-434: A cinder cone eruption, the magma has lost most of its gas content. This gas-depleted magma does not fountain but oozes quietly into the crater or beneath the base of the cone as lava. Lava rarely issues from the top (except as a fountain) because the loose, uncemented cinders are too weak to support the pressure exerted by molten rock as it rises toward the surface through the central vent. Because it contains so few gas bubbles,

128-407: A cinder cone is usually basaltic to andesitic in composition. It is often glassy and contains numerous gas bubbles "frozen" into place as magma exploded into the air and then cooled quickly. Lava fragments larger than 64 mm across, known as volcanic bombs , are also a common product of cinder cone eruptions. The growth of a cinder cone may be divided into four stages. In the first stage,

160-408: A low-rimmed scoria ring forms around the erupting event. During the second stage, the rim is built up and a talus slope begins to form outside the rim. The third stage is characterized by slumping and blasts that destroy the original rim, while the fourth stage is characterized by the buildup of talus beyond the zone where cinder falls to the surface (the ballistic zone ). During the waning stage of

192-576: A new vent. Eruptions continued for nine years, built the cone to a height of 424 meters (1,391 ft), and produced lava flows that covered 25 km (9.7 sq mi). The Earth's most historically active cinder cone is Cerro Negro in Nicaragua. It is part of a group of four young cinder cones NW of Las Pilas volcano. Since its initial eruption in 1850, it has erupted more than 20 times, most recently in 1995 and 1999. Satellite images suggest that cinder cones occur on other terrestrial bodies in

224-451: A tendency to form a cone at the surface. However, stratovolcanoes are able to form steeper sides whilst shield volcanoes only form very flat cones. The reason for this is that stratovolcanoes are composed largely of solid, eruptive material, whereas shield volcanoes are built up mainly by fluid lava flows. Over the course of time, after several eruptions , a cone of debris forms from the eruptive material. The natural conical shape so formed

256-698: Is a large shield volcano located in the Tharsis region of the planet Mars . It is the middle member of a chain of three volcanic mountains (collectively known as the Tharsis Montes ) that straddle the Martian equator between longitudes 235°E and 259°E. The volcano was discovered by the Mariner 9 spacecraft in 1971, and was originally called Middle Spot. Its name formally became Pavonis Mons in 1973. The equatorial location of its peak and its height make it

288-608: Is only possible where there is a stable, central crater. Many volcanoes are therefore only conical from one direction of view; from other angles they appear to have an irregular shape or bulges. Conical hills may form in tropical karst regions, such terrain being known as kegelkarst . A typical example of non-volcanic conical hills are the Chocolate Hills in Bohol on the Philippines . In almost all mountain regions of

320-450: Is simply a result of the fact that the amount of ejected material decreases with the radially distance from the crater . The layer of debris deposited is greater near the volcano than further away, so the volcano grows more rapidly close to the crater itself. The slope gradient of the resulting volcano is dependent both on the angle of repose as well as the speed at which the volcano is weathered. The angle of repose is, in turn, dependent on

352-469: Is too low to mobilize and remove dust once it is deposited. The bulk of the volcano's surface consists of lava flows of the early Amazonian age . The northern flanks of the volcano are highly faulted with grabens and normal faults concentric to the volcano's summit caldera. To its lower east flank, there is a chain of elliptical, or oval-shaped, pits, lined up down the center of a shallow trough. These features were formed by faulting and associated collapse;

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384-476: Is very low and the eruptions are spread out in space and time. This prevents any one eruption from establishing a system of " plumbing " that would provide an easy path to the surface for subsequent eruptions. Thus each eruption must find its independent path to the surface. Conical hill Conical hills or mountains occur in different shapes and are not necessarily geometrically-shaped cones; some are more tower-shaped or have an asymmetric curve on one side of

416-464: The Coalstoun Lakes volcanic field , and some cinder cones on Mauna Kea are monogenetic cinder cones. However, not all cinder cones are monogenetic, with some ancient cinder cones showing intervals of soil formation between flows that indicate that eruptions were separated by thousands to tens of thousands of years. Monogenetic cones likely form when the rate of magma supply to a volcanic field

448-540: The Geognostic Charter of the Kingdom of Saxony and its Adjacent Territories ( Erläuterungen zu Section VII der geognostischen Charte des Königreiches Sachsen und der angränzenden Länderabtheilungen ) thus: "The ordinary form of basalt and phonolitic hills is generally so wonderfully uniform that you can often recognize them even from a distance. They are cones. Of course, this typical form has many variations;

480-597: The Tharsis region, Pavonis Mons has a high albedo (reflectivity) and low thermal inertia , indicating that the volcano and surrounding areas are covered with large amounts of fine dust (see Martian surface ). The dust forms a mantle over the surface that obscures or mutes much of the fine-scale topography and geology of the region. Tharsis is probably dusty because of its high elevations. The summit experiences an atmospheric pressure of around 130 Pa (1.3 mbar), about 21% of Mars' mean surface pressure. The atmospheric density

512-418: The [normally] round base may be elongated, the peak may take the form of a rocky crest or ridge, ... but most forms can be reduced at least to a conical or a cone-segment shape. ... Flat ridges are then arranged in rows, out of which rise only a very isolated basalt or phonolite cones." In this work, which was published by Naumann and later revised by Bernhard Cotta , the most important hills are described in

544-616: The chain). The Tharsis Montes volcanoes lie along the crest of a northeast-trending rise (Tharsis bulge) that extends more than 3,000 km across the western equatorial region of Mars. Olympus Mons , the tallest volcano in the Solar System lies at the edge of the Tharsis bulge, about 1,200 km northwest of Pavonis Mons. Pavonis Mons is the smallest of the Tharsis Montes volcanoes, measuring about 375 km across and standing 14 km above Mars' mean surface level. As

576-436: The composition of the lava , its viscosity and rate of solidification, and also the amount of ejected loose rock . Many volcanoes tend to produce subsidiary craters or adventive cones . These are new openings formed on the sides of the volcano through which new material is ejected sometimes only on one side. As a result, these mountains lose their ideal conical shape. The formation of an almost perfect conical mountain or hill

608-594: The dispersion of ejected scoria particles. For example, cinder cones on Mars seem to be more than two times wider than terrestrial analogues as lower atmospheric pressure and gravity enable wider dispersion of ejected particles over a larger area. Therefore, it seems that erupted amount of material is not sufficient on Mars for the flank slopes to attain the angle of repose and Martian cinder cones seem to be ruled mainly by ballistic distribution and not by material redistribution on flanks as typical on Earth. Cinder cones often are highly symmetric, but strong prevailing winds at

640-518: The flanks of Mauna Kea , a shield volcano located on the island of Hawaii . Such cinder cones likely represent the final stages of activity of a mafic volcano. However, most volcanic cones formed in Hawaiian-type eruptions are spatter cones rather than cinder cones, due to the fluid nature of the lava. The most famous cinder cone, Paricutin , grew out of a corn field in Mexico in 1943 from

672-955: The hill. Typically, however, they have a circular base and smooth sides with a gradient of up to 30°. Such conical mountains are found in all volcanically-formed areas of the world such as the Bohemian Central Uplands in the Czech Republic , the Rhön in Germany or the Massif Central in France . The conical hill as a geomorphological term first appeared in the German language, as Kegelberg , coined by Goethe and geologists of his era. From their natural appearance these were mostly basaltic or phonolitic landforms in

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704-487: The ideal terminus for a space elevator , and it has often been proposed as a space elevator location, especially in science fiction. It is also an ideal location for a Sky Ramp . Pavonis Mons stands at the southern edge of the Tharsis quadrangle - approximately 400 km southwest of Ascraeus Mons (the northernmost of the Tharsis Montes) and 400 km northeast of Arsia Mons (the southernmost member of

736-443: The molten lava is denser than the bubble-rich cinders. Thus, it often burrows out along the bottom of the cinder cone, lifting the less dense cinders like corks on water, and advances outward, creating a lava flow around the cone's base. When the eruption ends, a symmetrical cone of cinders sits at the center of a surrounding pad of lava. If the crater is fully breached, the remaining walls form an amphitheater or horseshoe shape around

768-495: The relevant map sheets, for example: 33. The Mittenberg , a conical hill in the centre between Tollenstein , Schönfeld and Neuhütte; rock, coarse splinters, with grey feldspar crystals. Today the descriptors "cone", "conical hill" or "conical mountain" are mainly used as morphological terms in geography for a steep-sided, isolated hill or mountain, because they are not always seen or described in connexion with volcanic processes. All stratovolcanoes and shield volcanoes have

800-486: The scarp on each side of the trough is a fault line. Using MGS and Odyssey data, combined with developments in the study of glaciers, scientists suggest that glaciers once existed on Pavonis Mons and probably still do to some extent. Evidence for this includes concentric ridges (moraines "dropped" by glaciers), a knobby area (caused by ice sublimating), and a smooth section that flows over other deposits (debris-covered glacial ice). The ice could have been deposited when

832-583: The shape of a mathematical cone, hence why the term came to be used in the early geological literature. The first systematic geological mapping of the Kingdom of Saxony , proposed and started by Abraham Gottlob Werner , describes, in his later works, numerous mountains and hills of volcanic or subvolcanic origin as Kegel ("cone") or Kegelberg ("conical hill/mountain"). The term was introduced more definitively by Carl Friedrich Naumann in Notes to Section VII of

864-638: The solar system. On Mars, they have been reported on the flanks of Pavonis Mons in Tharsis , in the region of Hydraotes Chaos on the bottom of the Coprates Chasma , or in the volcanic field Ulysses Colles . It is also suggested that domical structures in Marius Hills (on the Moon) might represent lunar cinder cones. The size and shape of cinder cones depend on environmental properties as different gravity and/or atmospheric pressure might change

896-567: The tilt of Mars changed the climate, thereby causing more moisture to be present in the atmosphere. Studies suggest the glaciation happened in the Late Amazonian period, the most recent period in Mars chronology. Multiple stages of glaciation probably occurred. The ice present today represents one more resource for possible future colonization of the planet. Pavonis Mons is the middle of three volcanos (collectively known as Tharsis Montes) on

928-467: The time of eruption can cause a greater accumulation of cinder on the downwind side of the vent. Some cinder cones are monogenetic , forming from a single short eruptive episode that produces a very small volume of lava. The eruption typically last just weeks or months, but can occasionally last fifteen years or longer. Parícutin in Mexico, Diamond Head , Koko Head , Punchbowl Crater , Mt Le Brun from

960-456: The vent to form a cone that often is symmetrical; with slopes between 30 and 40°; and a nearly circular ground plan. Most cinder cones have a bowl-shaped crater at the summit. Cinder cones range in size from tens to hundreds of meters tall. They are composed of loose pyroclastic material ( cinder or scoria ), which distinguishes them from spatter cones , which are composed of agglomerated volcanic bombs . The pyroclastic material making up

992-440: The vent. Basaltic cinder cones are the most characteristic type of volcano associated with intraplate volcanism . They are particularly common in association with alkaline magmatism , in which the erupted lava is enriched in sodium and potassium oxides . Cinder cones are also commonly found on the flanks of shield volcanoes , stratovolcanoes , and calderas . For example, geologists have identified nearly 100 cinder cones on

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1024-802: The world, conical peaks may be formed by erosion processes, but they are not usually isolated landforms. Often they arise through the formation of ordinary riverine meanders . But they can also result from the action of an entrenched river that has cut deeply into a plateau . The resulting cutoff meander spur may be cone-shaped. The artificially created hills or mounds associated, for example, with mining also tend to be cone-shaped. These artificial hills are also free-standing and, once tipping has finished, they may become conical hills overgrown with vegetation. However, as artificial features they are classed as spoil tips rather than natural hills. Pavonis Mons Pavonis Mons / p ə ˈ v oʊ n ɪ s ˈ m ɒ n z / ( Latin for " peacock mountain")

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