Schists in a sentence

Most schists are mica schists, but graphite and chlorite schists are also common.

The graphitic schists may readily be believed to represent sediments once containing coal or plant remains; there are also schistose ironstones ( hematite -schists), but metamorphic beds of salt or gypsum are exceedingly uncommon.

A subgroup is the andalusite -, staurolite -, kyanite - and sillimanite -schists which usually make their appearance in the vicinity of gneissose granites, and have presumably been affected by contact metamorphism.

For that reason many of these rocks split readily in one direction along mica-bearing zones ( schists ).

Geologically, the island consists of gneiss and argillaceous schists with occasional tufts and other sedimentary layers from which fossils have been recovered.

Gneisses also, as a rule, contain more feldspar than schists do, and are tougher and less fissile.

Hence, it can be found in mica schists and in contact with metamorphic deposits of dolomitic marble.

In gneisses these alternating folia are sometimes thicker and less regular than in schists, but most importantly less micaceous; they may be lenticular, dying out rapidly.

Magnesium-rich tourmalines, dravites, are generally restricted to schists and marble.

Near the memorial to the climbers, who have died on K2, above Base Camp on the south spur, thin impure marbles with quartzites and mica schists, called the Gilkey-Puchoz sequence, are interbanded within the orthogneisses.

Rocks that were originally sedimentary and rocks that were undoubtedly igneous may be metamorphosed into schists and gneisses.

The Allochtons are mainly in the area of lustrous schists and ophiolites corresponding to the eastern relief ( Cap Corse and Castagniccia)".

The more completely altered forms of these rocks are platy, green chloritic schists; in these, however, structures indicating their original volcanic nature only sparingly occur.

The schists are classified principally according to the minerals they consist of and on their chemical composition.

The word schist is derived ultimately from the Greek word σχίζειν schízein meaning "to split", citation which is a reference to the ease with which schists can be split along the plane in which the platy minerals lie.

Usually, however, it is possible to distinguish between sedimentary and igneous schists and gneisses.