Question

Which discontinuity lies between mantle and the outer core?

• A. Conrad
• B. Gutenberg
• C. Lehmann
• D. Repetti

Hint:

Remember the important discontinuities:
• Conrad $\rightarrow$ Upper crust -- Lower crust
• Gutenberg $\rightarrow$ Mantle -- Outer core
• Lehmann $\rightarrow$ Outer core -- Inner core
• Repetti $\rightarrow$ Upper mantle -- Lower mantle

Answer 1

The Correct Option is B

Concept: The Earth's interior is divided into different layers separated by seismic discontinuities, where seismic wave velocities change abruptly due to changes in composition or physical state.

Step 1: Identify the major discontinuities.
• Conrad Discontinuity $\rightarrow$ Between the upper and lower continental crust.
• Gutenberg Discontinuity $\rightarrow$ Between the mantle and the outer core.
• Lehmann Discontinuity $\rightarrow$ Between the outer core and the inner core.
• Repetti Discontinuity $\rightarrow$ Between the upper and lower mantle.

Step 2: Locate the mantle--outer core boundary. The boundary separating the mantle from the liquid outer core is known as the Gutenberg Discontinuity. \[ \boxed{\text{Mantle} \longrightarrow \text{Gutenberg Discontinuity} \longrightarrow \text{Outer Core}} \] Therefore, the correct option is \[ \boxed{(B)\;\text{Gutenberg}.} \]