Which boundary marks the transition from crust to mantle?

Which boundary marks the transition from crust to mantle?

• A. Moho (Mohorovicic discontinuity)
• B. Gutenberg boundary
• C. Lehmann discontinuity
• D. Core-mantle boundary

Answer: (A)

The transition from crust to mantle is marked by the Mohorovicic discontinuity, the boundary where seismic waves experience an abrupt change in velocity due to a switch from crustal rocks to mantle rocks. This boundary sits at the base of the crust and defines the crust–mantle interface. The other names refer to different boundaries: the Gutenberg boundary is between the lower mantle and the outer core, the Lehmann discontinuity is between the outer and inner core, and the core–mantle boundary is between the mantle and the outer core. So the Moho is the boundary that specifically delineates crust from mantle.

The transition from crust to mantle is marked by the Mohorovicic discontinuity, the boundary where seismic waves experience an abrupt change in velocity due to a switch from crustal rocks to mantle rocks. This boundary sits at the base of the crust and defines the crust–mantle interface. The other names refer to different boundaries: the Gutenberg boundary is between the lower mantle and the outer core, the Lehmann discontinuity is between the outer and inner core, and the core–mantle boundary is between the mantle and the outer core. So the Moho is the boundary that specifically delineates crust from mantle.