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For instance, the small calcite crystals in the sedimentary rocks limestone and chalk change into larger crystals in the metamorphic rock marble. [13] In metamorphosed sandstone , recrystallization of the original quartz sand grains results in very compact quartzite , also known as metaquartzite, in which the often larger quartz crystals are ...
Dislocation creep is a non-linear (plastic) deformation mechanism in which vacancies in the crystal glide and climb past obstruction sites within the crystal lattice. [1] These migrations within the crystal lattice can occur in one or more directions and are triggered by the effects of increased differential stress.
List of rocks on Mars – Alphabetical list of named rocks and meteorites found on Mars; Rock cycle – Transitional concept of geologic time; List of rock formations: for a list of unusual or culturally significant rock outcrops; Leaverite – Rock in the field that looks interesting but is actually not
Other minerals, such as olivines, pyroxenes, hornblende, micas, feldspars, and quartz, may be found in metamorphic rocks but are not necessarily the result of the process of metamorphism. These minerals can also form during the crystallization of igneous rocks. They are stable at high temperatures and pressures and may remain chemically ...
Because rocks are essentially aggregates of minerals, we can think of them as poly-crystalline materials. Dislocations are a type of crystallographic defect which consists of an extra or missing half plane of atoms in the periodic array of atoms that make up a crystal lattice.
Neomorphism is considered aggrading when recrystallization results in an any increase in crystal size. The crystal mosaics of the original mineral or crystal formation(s) often experience deterioration in the process and are eventually replaced with either crude crystalline mosaics or polymorphs. Both the resultant crystalline mosaics and/or ...
In geology, shear is the response of a rock to deformation usually by compressive stress and forms particular textures. Shear can be homogeneous or non-homogeneous, and may be pure shear or simple shear. Study of geological shear is related to the study of structural geology, rock microstructure or rock texture and fault mechanics.
Layers of rock that fold into a hinge need to accommodate large deformations in the hinge zone. This results in voids between the layers. These voids, and especially the fact that the water pressure is lower in the voids than outside of them, act as triggers for the deposition of minerals.