Question

Define the term parent-rock

Answer 1

Parent rock, also referred to as substratum, refers to the original rockfrom which something else was formed. It is mainly used in the context of soil formation where the parent rock(or parent material) normally has a large influence on the nature of the resulting soil.
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Answer 2

In the earth sciences, parent rock, also sometimes substratum, is the original rock from which younger rock or soil is formed. Parent rock can be sedimentary, igneous or metamorphic. In the context of metamorphic rocks, the parent rock is the original rock before metamorphism occurred.