lower mantle

8.1

A deep, solid layer inside the Earth above the outer core, about 660 to 2,900 km below the surface

noun

Specialized

: manto inferior

Geologists study the lower mantle to understand how heat and pressure affect the Earth's materials at great depths.
upper and lower mantle

Examples

I was referring to current loops, where the lower mantle meets the liquid core?

Fiction book (1990)
The composition of the lower mantle may differ significantly from that of the upper mantle due to pressure changes at such depths.
And the green are the lower mantle after the impact of event.
Perovskite, the structure typical of silicates in the lower mantle, can accommodate no more than 15% iron.

Academic text (2005)
Vigorous thermal convection mixes the composition of the upper and lower mantle.

Academic text (2005)
Scientists believe that the lower mantle plays a crucial role in the movement of tectonic plates beneath the Earth's surface.

How Deep

core

Specialized

130 4.9

lower mantle

Specialized

8.1

upper mantle

Specialized

6.7

crust

Specialized

47 4.9

Surface Forms

lower mantle singular

lower mantles plural

Morphology

lower + mantle

The meaning 'the part of the Earth's mantle that is lower/downward' is directly and compositionally derived from 'lower' (positioned below) + 'mantle' (the silicate layer beneath the crust). This follows a common adjective + noun pattern (cross-linguistically frequent), so a B1 learner who knows both words can infer the general meaning even if they may not know the precise depth range.

Etymology

Lower mantle The name lower mantle comes from the image of the Earth wearing a mantle like a 'cloak', with lower meaning the deeper part beneath the upper layers. So, lower mantle refers to the deep layer inside the Earth below the upper mantle.