primary gneissic banding

primary gneissic banding

[′prī‚mer·ē ¦nī‚sik ′band·iŋ] (petrology) A kind of banding developed in certain igneous (plutonic) rocks of heterogeneous composition, produced by the admixture of two magmas only partly miscible or by magma intimately admixed with country rock into which it has been injected along planes of bedding or foliation.