Breach (rock)

See also: Breach

The breaches are, with the conglomerates and the tillites one of the three kinds of rocks which train the family of the conglomerates. The conglomerates are detrital rocks, i.e. resulting from the mechanical degradation of other rocks, generally sedimentary, sometimes volcanic, made up of fragments linked by a natural cement. While the conglomerates agglomerate elements rounded (rollers), the breaches contain angular elements. The tillites are conglomerates where coexist the angular elements rounded and pieces.

etymology

The term of breach comes from the Indo-European root bhrg : to break. One finds this root in several languages of Europe:

in Italian, breccia : hone broken
in German, brechen : to break

definition

A breach is a Roche made up from at least 50% of angular elements (whose size is higher than 2 mm) taken in a natural cement. The Lithologie of the elements makes it possible to distinguish a monogenic breach made up of elements of comparable nature and a polygenic breach made up of elements of different nature.

There exist three types of breaches:

the sedimentary breach is a detrital rock of the group of the conglomerate S (class of the Rudite S sensu Grabau 1904), formed by the accumulation of angular elements having undergone a weak transport. One can divide the sedimentary breaches into three groups according to the nature of the elements and cement:

#brèche of intraformationnelle slope

#brèche

#brèche eluvial

the tectonic breach is resulting from the cementing of fragments of rock created in a tectonic context.

the volcanic breach is made up of fragments of rocks magma ic ticks Volcan and of cement of S and of Lapilli S.

ashes

the tectonic breaches are of origin Pyroclastique. Formation: bed rock because of seismic phenomena, but the unit is not disunited completely. The zones of fractures are quickly filled by mineral solutions.

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