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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.
The reaction between certain fluids and the minerals the rock is composed of can lower the stress required for fracture below the stress required throughout the rest of the rock. For instance, water and quartz can react to form a substitution of OH molecules for the O molecules in the quartz mineral lattice near the fracture tip.
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.
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.
Solidified lava flow in Hawaii Sedimentary layers in Badlands National Park, South Dakota Metamorphic rock, Nunavut, Canada. Geology (from Ancient Greek γῆ (gê) 'earth' and λoγία () 'study of, discourse') [1] [2] is a branch of natural science concerned with the Earth and other astronomical objects, the rocks of which they are composed, and the processes by which they change over time. [3]
In geology, texture or rock microstructure [1] refers to the relationship between the materials of which a rock is composed. [2] The broadest textural classes are crystalline (in which the components are intergrown and interlocking crystals), fragmental (in which there is an accumulation of fragments by some physical process), aphanitic (in which crystals are not visible to the unaided eye ...
The most obvious evidence of diastrophic movement can be seen where sedimentary rocks have been bent, broken or tilted. Such non-horizontal strata provide visual proof of movement. Diastrophic movement can be classified as two types, folding and faulting, tilted beds usually are part of a larger syncline or anticline .
Topographic map showing detachment folds in the eastern Sichuan Basin, China.. A detachment fold, in geology, occurs as layer parallel thrusting along a decollement (or detachment) develops without upward propagation of a fault; the accommodation of the strain produced by continued displacement along the underlying thrust results in the folding of the overlying rock units.