GENERAL GEOLOGY

Detailed explanation-1: -Gneiss . Gneiss is a type of metamorphic rock that forms when a sedimentary or igneous rock is exposed to extreme temperatures and pressure. When this happens, virtually no traces of the original rock remain. Gneiss rocks are characterized by their arrangement of minerals into long bands.

Detailed explanation-2: -Figure 10.17 Gneiss, a coarse-grained, high grade metamorphic rock, is characterized by colour bands.

Detailed explanation-3: -Some kinds of metamorphic rocks–granite gneiss and biotite schist are two examples–are strongly banded or foliated. (Foliated means the parallel arrangement of certain mineral grains that gives the rock a striped appearance.)

Detailed explanation-4: -Schist is made of medium-grained interlocking crystals. Its shiny appearance is due to the mineral mica. Crystals line up to give the rock wrinkly layers – this is called foliation.

Detailed explanation-5: -Foliated rocks are a type of metamorphic rock that has a characteristic banded (or striped) pattern. Due to extreme heat and pressure, rock minerals will flatten to create parallel layers needed to form the striped patterns in foliated rocks.