Answer:
Brittle Deformation
Step-by-step explanation:
Brittle Deformation – Faults and Joints
Brittle-Ductile Properties of the Lithosphere
We all know that rocks near the surface of the Earth behave in a brittle manner. Crustal rocks are composed of minerals like quartz and feldspar which have high strength, particularly at low pressure and temperature. As we go deeper into the Earth the strength of these rocks initially increases.
At a depth of about 15 km, we reach a point called the brittle-ductile transition zone. Below this point rock strength decreases because fractures become closed and the temperature is higher, making the rocks behave in a ductile manner. At the base of the crust the rock type changes to peridotite which is rich in olivine. Olivine is stronger than the minerals that make up most crustal rocks, so the upper part of the mantle is again strong. But, just as in the crust, increasing temperature eventually predominates and at a depth of about 40 km, the brittle-ductile transition zone in the mantle occurs. Below this point, rocks behave in an increasingly ductile manner.
Be Brinly.