Difference Between Foliation and Layering

Foliation vs Layering

Foliation and layering present as patterns in both sedimentary and metamorphic rocks. Telling the difference between both would entail physical assessment of the different rocks, either visually checking the components or looking at the mineral closely. Both foliation and layering are used for geological purposes.

Foliation

Foliation by definition means a penetrating pattern which is due to the realignment of minerals such as mica minerals. Foliation is also used to describe the banded physical appearance of metamorphic rocks. Therefore, metamorphic rock foliation is a product of the stress direction principle. To decipher the direction of shortening, close observation of the perpendicular formation has to be done.

Layering

On the other hand, layering can be described as formation of layers of rocks over the other. The small rocks embedded on the sedimentary rocks will reflect the type of environment during the time it was deposited. In other words, sedimentary rocks with layering will have thin layers of coarse and fine sediments or fragments. Upon close observation, one will be able to notice marks, trace fossils and soft sediment deformation.

Difference between Foliation and Layering

To differentiate foliation and layering, let us begin with how they are formed. Foliation is based on the principle of stress while layering is caused by small mica fragments embedding on the rocks. Foliation is formed by fire and stress; layering is caused by thin embedding of both coarse and fine deposits. Also, foliation is due to the alteration of minerals from heat and pressure. Layering, on the other hand, is seasonal or event based. In terms of physical aspect, foliation has layers or striations while layering has marks on them.

Both foliation and layering will help geologist understand particular axial movement or seasonal change over a period of time. This is a particular subject especially in geology which is interests a lot of students. Understanding everything might take time but being able to learn the difference will indeed become helpful.