gneissic banding मीनिंग इन हिंदी

Ptygmatic folds are formed by highly plastic ductile deformation of the gneissic banding, and thus have little or no relationship to a defined foliation, unlike most regular folds.
Schistosity and gneissic banding ( the two main types of foliation ) are formed by directed pressure at elevated temperature, and to interstitial movement, or internal flow arranging the mineral particles while they are crystallizing in that directed pressure field.
Examples include the bands in gneiss ( gneissic banding ), a preferred orientation of planar " large " mica flakes in schist ( Schistocity ), the preferred orientation of " small " mica flakes in phyllite ( with its planes having a silky sheen, called " phylitic luster "-the Greek word, " phyllon ", also means " leaf " ), the extremely fine grained preferred orientation of clay flakes in slate ( called " slaty cleavage " ), and the layers of flattened, smeared, pancake-like clasts in metaconglomerate.