Question map
Which one among the following is a primary rock?
Explanation
Igneous rocks are classified as primary rocks because they are formed directly from the solidification of molten magma or lava [2]. Magma is the source material for all rocks; when it cools and crystallizes, it forms igneous rocks, which serve as the parent material for other rock types in the rock cycle [2]. Sedimentary rocks are formed from the fragments and deposits derived from pre-existing igneous or metamorphic rocks through weathering and erosion [1][t1]. Metamorphic rocks are formed when existing rocks (igneous, sedimentary, or older metamorphic) undergo transformation due to intense heat and pressure [c5][t3]. Because igneous rocks are the first to form from the Earth's internal molten state and provide the foundational material from which sedimentary and metamorphic rocks are subsequently derived, they are uniquely termed 'primary rocks' [c1][c2].
Sources
- [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 13: Types of Rocks & Rock Cycle > 13.1. Igneous Rocks or Primary rocks > p. 169
- [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 13: Types of Rocks & Rock Cycle > 13.4. Rock Cycle > p. 174