In
geology
Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Ea ...
, a cryptoexplosion structure (or cryptovolcanic structure) is an explosion of unknown cause. The term is now largely obsolete. It was once commonly used to describe sites where there was geological evidence of a large-scale explosion within the
Earth's crust, but no definitive evidence for the cause such as normal
volcanic rock
Volcanic rock (often shortened to volcanics in scientific contexts) is a rock formed from lava erupted from a volcano. In other words, it differs from other igneous rock by being of volcanic origin. Like all rock types, the concept of volcanic ...
s. These sites are usually circular with signs of anomalous rock deformation contrasting with the surrounding region, and often showing evidence that crustal material had been uplifted and/or blown outwards. The assumption was that some unusual form of volcanism, or a gas explosion originating within the crust, was the cause. The use of the term went away with the rise of the science of impact crater recognition in the late 20th century. Most structures described as cryptoexplosions turned out to be eroded
impact crater
An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact crater ...
s, caused by the impact of
meteorites. Today geologists discount former cryptoexplosion theories.
See also
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Impact crater
An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact crater ...
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Impact structure
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Astrobleme
An impact structure is a generally circular or craterlike geologic structure of deformed bedrock or sediment produced by impact on a planetary surface, whatever the stage of erosion of the structure. In contrast, an impact crater is the sur ...
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Impact event
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Traces of Catastrophe
''Traces of Catastrophe: A Handbook of Shock-Metamorphic Effects in Terrestrial Meteorite Impact Structures'' is a book written by Bevan M. French of the Smithsonian Institution. It is a comprehensive technical reference on the science of impact ...
References
Impact craters
Obsolete geology theories
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