Question

Metamorphic rocks are formed due to:

• A. Cooling of magma
• B. Weathering only
• C. Heat and pressure acting on existing rocks
• D. Deposition of sediments

Hint:

Rock cycle: \[ \boxed{ \begin{aligned} \text{Cooling of magma} &\rightarrow \text{Igneous rocks} \text{Deposition of sediments} &\rightarrow \text{Sedimentary rocks} \text{Heat and pressure} &\rightarrow \text{Metamorphic rocks} \end{aligned} } \]

Answer 1

The Correct Option is C

Concept: Metamorphic rocks are formed when pre-existing igneous, sedimentary, or older metamorphic rocks undergo physical and chemical changes due to high temperature, high pressure, and chemically active fluids without melting.

Step 1: Understand metamorphism. During metamorphism,
• Mineral composition changes.
• Texture and structure are altered.
• The rock remains in the solid state.

Step 2: Identify the correct process. Metamorphic rocks are produced by the action of heat and pressure on existing rocks. \[ \boxed{\text{Existing Rock} \xrightarrow{\text{Heat + Pressure}} \text{Metamorphic Rock}} \] Therefore, the correct option is \[ \boxed{(C)\;\text{Heat and pressure acting on existing rocks}.} \]