Question

Describe two processes which sedimentary rocks change into metamorphic rocks

Answer 1

(i) In the mountain building process,sedimentary rocks are compressed and due to this pressure heat is generated.This heat modifies the structure of the original rocks.

The process above is referred to as thermal-dynamic metamorphism.

(ii) When the weight of the overlying rock layers creates pressure on the lower layers,it leads to change in structure or grain alignment of the rocks.

The entire process is called dynamic metamorphism.

(iii) During volcanic eruptions,hot magma may intrude a sedimentary rock.The rock grains will re-crystallize due to heat to form new minerals.The process is known as thermal or contact metamorphism.