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This results in a banded, or foliated, rock, with the bands showing the colors of the minerals that formed them. Foliated rock often develops planes of cleavage . Slate is an example of a foliated metamorphic rock, originating from shale , and it typically shows well-developed cleavage that allows slate to be split into thin plates.
Some form of recovery process, such as dislocation climb or grain-boundary migration must also be active. Slipping of the dislocation results in a more stable state for the crystal as the pre-existing imperfection is removed. It requires much lower differential stress than that required for brittle fracturing. This mechanism does not damage the ...
Sedimentary rocks are formed through the gradual accumulation of sediments: for example, sand on a beach or mud on a river bed. As the sediments are buried they get compacted as more and more material is deposited on top. Eventually the sediments will become so dense that they would essentially form a rock. This process is known as lithification.
These rocks are fine-grained and sometimes cool so rapidly that no crystals can form and result in a natural glass, such as obsidian, however the most common fine-grained rock would be known as basalt. Any of the three main types of rocks (igneous, sedimentary, and metamorphic rocks) can melt into magma and cool into igneous rocks. [2]
Cumulate rock – Igneous rocks formed by the accumulation of crystals from a magma either by settling or floating. Flow banding – Bands or layers that can sometimes be seen in rock that formed from magma; Fractional crystallization (chemistry) – Method for refining substances based on differences in their solubility
The types and abundance of minerals in a rock are determined by the manner in which it was formed. Most rocks contain silicate minerals, compounds that include silica tetrahedra in their crystal lattice, and account for about one-third of all known mineral species and about 95% of the earth's crust. [6] The proportion of silica in rocks and ...
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.
The equations that govern the deformation of jointed rocks are the same as those used to describe the motion of a continuum: [13] ˙ + = ˙ = = ˙: + = where (,) is the mass density, ˙ is the material time derivative of , (,) = ˙ (,) is the particle velocity, is the particle displacement, ˙ is the material time derivative of , (,) is the Cauchy stress tensor, (,) is the body force density ...