Cataclasite is a type of cataclastic rock that is formed by fracturing and comminution

Comminution

Comminution is the process in which solid materials are reduced in size, by crushing, grinding and other processes. It occurs naturally during faulting in the upper part of the crust and is an important operation in mineral processing, ceramics, electronics and other fields. Within industrial uses,...

 during faulting. It is normally cohesive

Cohesion (geology)

Cohesion is the component of shear strength of a rock or soil that is independent of interparticle friction.In soils, true cohesion is caused by one of three things:# Electrostatic forces in stiff overconsolidated clays...

 and non-foliated

Foliation (geology)

Foliation is any penetrative planar fabric present in rocks. Foliation is common to rocks affected by regional metamorphic compression typical of orogenic belts. Rocks exhibiting foliation include the standard sequence formed by the prograde metamorphism of mudrocks; slate, phyllite, schist and...

, consisting of angular clasts in a finer-grained matrix

Matrix (geology)

The matrix or groundmass of rock is the finer grained mass of material in which larger grains, crystals or clasts are embedded.The matrix of an igneous rock consists of finer grained, often microscopic, crystals in which larger crystals are embedded. This porphyritic texture is indicative of...

.

Types of cataclasite

There are many varieties of cataclasite, classified by the percentage of the volume

Volume

Volume is the quantity of three-dimensional space enclosed by some closed boundary, for example, the space that a substance or shape occupies or contains....

 formed from the matrix.

Protocataclasite

Protocataclasite is a type of cataclasite in which the matrix takes up less than 50% of the total volume.

Mesocataclasite

Mesocataclasite is a type of cataclasite in which the matrix occupies between 50 and 90 percent of the total volume.

Ultracataclasite

Ultracataclasite is a type of cataclasite characterized by a matrix occupying greater than 90% of the total volume.

Foliated Cataclasite

Foliated cataclasite is a type of cataclasite with a significant content of clay. Grades through to fault (clay) gouge

Fault gouge

Fault gouge is an unconsolidated tectonite with a very small grain size. Fault gouge has no cohesion, it is normally an unconsolidated rock type, unless cementation took place at a later stage...

 when the proportion of clay is greater than 70%.

Formation

Cataclasite forms by the progressive fracturing of mineral

Mineral

A mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...

 grains and aggregates, a process known as cataclasis. The fracturing continues until a distribution of clast sizes is developed that allows the sliding of clasts past each other, without high enough frictional stresses to further fracture the rock significantly. From then on deformation is accommodated by continued sliding and rolling of fragments, a deformation mechanism

Deformation mechanism

In structural geology, metallurgy and materials science, deformation mechanisms refer to the various mechanisms at the grain scale that are responsible for accommodating large plastic strains in rocks, metals and other materials.-Mechanisms:...

known as cataclastic flow. In poorly consolidated or unconsolidated sediments, deformation in fault zones also occurs by rolling and sliding of grains but the porosity of the rock accommodates the resulting strains without significant grain fracturing.