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An explosion crater is a type of crater formed when material is ejected from the surface of the ground by an explosion at or immediately above or below the surface. Stylised cross-section of a crater formed by a below-ground explosion. A crater is formed by an explosion through the displacement and ejection of material from the ground.
A volcanic crater is a bowl-shaped depression in the ground caused by volcanic activity, usually located above the volcano's vent. [11] During volcanic eruptions, molten magma and volcanic gases rise from an underground magma chamber, through a conduit, until they reach the crater's vent, from where the gases escape into the atmosphere and the magma is erupted as lava.
One possible mechanism for the formation of tektites is by the jetting of highly shocked and superheated melt during the initial contact/compression stage of impact crater formation. Alternatively, various mechanisms involving the dispersal of shock-melted material by an expanding vapor plume, which is created by a hypervelocity impact, have ...
A central-peak crater is the most basic form of complex crater. A central-peak crater can have a tightly spaced, ring-like arrangement of peaks, thus be a peak ring crater, though the peak is often single. [3] Central-peak craters can occur in impact craters via meteorites. An Earthly example is Mistastin crater, in Canada. [1]
Alga crater on Mars is a possible site for preserved ancient life, after detection of an impact glass deposit. [4] Impactite has been found, for example, at the following impact craters and structures: Alamo bolide impact (Late Devonian), Nevada, United States; Alga crater on the planet Mars [4] Barringer crater, Arizona, United States [7]
[3] The most common form of trinitite is green fragments of 1–3 cm thick, smooth on one side and rough on the other; this is the trinitite that cooled after landing still-molten on the desert floor. [22] [20] Around 30% of trinitite is void space, although quantities vary greatly between samples.
At the surface expression of such hydrothermal systems, low-temperature volcanic gases (<400 °C) are either emanating as steam-gas mixtures or in dissolved form in hot springs. At the ocean floor, such hot supersaturated hydrothermal fluids form gigantic chimney structures called black smokers, at the point of emission into the cold seawater.
One of the most spectacular types of pyroclastic deposit is an ignimbrite, which is the deposit of a ground-hugging pumiceous pyroclastic density current (a rapidly flowing hot suspension of pyroclasts in gas). Ignimbrites may be loose deposits or solid rock, and they can bury entire landscapes.