Geography & Earth
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Isostatic Root Depth

Depth of a mountain's crustal root floating in the mantle.

Formula

r=ρc hρm−ρcr = \frac{\rho_c\,h}{\rho_m - \rho_c}

Variables

\rho_cCrust density
\rho_mMantle density
hMountain height

Example

A 5 km peak needs a root roughly 28 km deep

Did You Know?

Mountains float on the mantle like icebergs, with deep hidden roots — which is why the Himalayas sit on crust nearly twice normal thickness.

geologyisostasymountains