Fault breccia

Cataclasites are rocks whose mineral aggregates and rock components were reduced by mechanical stress or dynamic recrystallization. The process is called cataclasis and is a special case of metamorphosis ( dislocation metamorphism ).

Generally

Tectonic processes are on rocks and the crystals forming them inner and outer deformation caused (fracture and / or collapse of the crystal grain ). At sufficiently high temperatures, a transition from mechanical failure of the minerals for the plastic deformation takes place, which can lead to the formation of a characteristic texture.

Cataclasites occur in zones where rock packages are laterally or vertically offset from each other. This fault or shear zones are a widespread phenomenon in the form of faulting. We distinguish between unconsolidated and consolidated cataclasites.

Raw Unpaved cataclasites

The rocks with unconsolidated structure made ​​of fine material and coarse fragments. They often occur in rock formations that were relatively close to the Earth surface during the tectonic stress.

In fissure surfaces to cataclastic debris can accumulate through replenishment. Here hydrothermal solutions can flow through and create a secondary mineralization (certain veins ). Notoriety learn such structures if they lead in mining and tunneling to significant tunneling problems, because large quantities unconsolidated cataclastic slip into the work area. There are rarely uttered the term fault gouge, which actually refers to a regional geological facies.

Depending on the particle size one speaks of Latvians clefts (mainly fine and very fine-grained ), Ruscheln (grain size between millimeter and centimeter range ) and unconsolidated tectonic breccia ( fragments roughly until the decimeter ).

Solidified cataclasites

The solidified forms are usually a result of metamorphic processes in depth. Here, a conversion and Neukristallisation of mineral constituents took place that lead to the ultimate solidification of the rock. Basically, you can cataclasites ( by brittle deformation or breakage) of the mylonites differ (plastic / ductile deformation / flow texture).

In this group, the following classification is made:

Unfoliierte group ( cataclasites )

The rocks of this group are unfoliiert.

• Ultrakataklasit

Here the rock constituents are predominantly fine-grained.

• Tectonic Mikrobrekzie

All rock constituents are affected by cataclastic changes.

• Solidified tectonic breccia

The rock has shaped fragments into a fine-grained matrix.

• Solidified tectonic conglomerate

The cataclastic components indicate the edges more or less rounded shapes.

Foliated group ( mylonites )

Main article → mylonite

The mylonites are now considered as an independent rock group. But you are like cataclasites originated in tectonic fault zones and ( porphyroclasts ) in Protomylonit, Orthomylonit and Ultramylonit be according to the proportion of deformed minerals at unchanged components of the parent material classified. In addition, the name of the parent material ( granite Protomylonit ) or the most common mineral ( quartz Orthomylonit ) is prepended to name a Mylonitgestein detail.