The boundary between this layer and the one below it is the Gutenberg discontinuity, which lies at the bottom of its D'' (D-double-prime) section.
The lower portion of this layer contains many low-velocity zones. The boundary between this layer and the one below it is the Gutenberg discontinuity, which lies at the bottom of its D'' (D-double-prime) section. Rock types found within this layer include olivine and peridotite, and its upper limit is marked by the Moho. This layer's upper portion contains the asthenosphere, which is subject to convection. Namesake plumes from this layer can reach the surface at hot spots. For 10 points, name this layer of the Earth found above the outer core and below the crust.
The lower portion of this layer contains many low-velocity zones.
{mantle}