What Causes Granite To Turn Into Gneiss

Granites at the surface are exposed to weathering in which they break down into mostly quartz and feldspars.

What causes granite to turn into gneiss.

When subjected to intense heat and pressure granite will. If it is part of a mountain it gets weathered eroded and transported to the ocean. Not all gneiss is obtained from granite and there are also diorite gneiss biotite gneiss garnet gneiss and so on. Heat and pressure cause granite to become gneiss and change sandstone into quartzite.

These rocks primarily consist of quartz feldspar and mica. By heat or pressure sometimes both. More fleshed out fuller and still correct answer. Gneiss is a metamorphic rock granite is an igneous rock and sandstone is a sedimentary rock.

All rocks undergo a series of processes called the rock cycle where one type of rock changes into another. Well gneiss dosent turn into granite. Another important structural change is the development of foliation or linear appearance in a gneiss. Granite turns into gneiss.

Metamorphic rocks form from heat and pressure which changes the original or parent rock into a completely new rock. The mineral composition of both granite and gneiss is same but alteration of granite because of very high pressure and temperature leads to the formation of gneiss. Despite its highly altered nature gneiss can preserve chemical evidence of its history especially in minerals like zircon which resist metamorphism. The appearance of granular minerals is what marks the transition into gneiss.

Intense heat and pressure can also metamorphose granite into a banded rock known as granite gneiss this transformation is usually more of a structural change than a mineralogical transformation. These minerals are then transported in streams and rivers and often end up as sediments in the oceans. With still more metamorphism gneisses can turn to migmatite and then totally recrystallize into granite. This is due to the long minerals in the original granite lining up perpendicular to a regional stress field.

There are no chemical changes but structural. If the granite gets buried deep in the crust it often changes to a gneiss. The change from granite to gneiss is not mineralogical i e. Granite turns into gneiss.

By heat or pressure sometimes both. Short succinct and correct answer.