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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.
When magma rises up through a crack in Earth's crust and makes contact with a shallow body of groundwater, rapid expansion of heated water vapor and volcanic gases can cause a series of explosions. A relatively shallow crater (known as a maar) is left, and a rock-filled fracture (the actual diatreme) in the crust. Where diatremes breach the ...
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]
It then becomes a meteor and forms a fireball, also known as a shooting star; astronomers call the brightest examples "bolides". Once it settles on the larger body's surface, the meteor becomes a meteorite. Meteorites vary greatly in size. For geologists, a bolide is a meteorite large enough to create an impact crater. [2]
Allende is classified as a CV3 carbonaceous chondrite: the chemical composition, which is rich in refractory elements like calcium, aluminum, and titanium, and poor in relatively volatile elements like sodium and potassium, places it in the CV group, and the lack of secondary heating effects is consistent with petrologic type 3 (see meteorites ...
At Cap d’Erquy, along the northern coast of France, the satellite system picked up on potential structures buried into a crater, according to the release, and the researchers took a closer look.
Iridium is a chemical element; it has symbol Ir and atomic number 77. A very hard, brittle, silvery-white transition metal of the platinum group , it is considered the second-densest naturally occurring metal (after osmium ) with a density of 22.56 g/cm 3 (0.815 lb/cu in) as defined by experimental X-ray crystallography .
Kamacite is made up of a repeating unit of α-(Fe, Ni), Fe 0.9 Ni 0.1, in which both iron and nickel have the valence zero (Fe 0 and Ni 0) as they are metallic native elements commonly found in iron meteorites. Besides trace elements, it is normally considered to be made up of 90% iron and 10% nickel but can have a ratio of 95% iron and 5% nickel.