isostasy
Floating continental balance
Isostasy is the principle that Earth's crust floats in gravitational equilibrium on the denser mantle beneath, like ice floating on water.
Mountains have deep roots extending downward, while ocean floors sit higher on the mantle.
When weight is added or removed—by glaciers forming or melting, for instance—the crust slowly rises or sinks to restore balance: The land is still rebounding from isostasy after the ice sheets retreated.
Crust plus upper mantle
- asthenosphereDuctile upper mantle layer
- compensationPayment for services rendered
- crustalOf outer rock layer
- subsidenceGradual ground sinking
uplift · flexure · earth's crust · topography · buoyancy · mass balance · loading · unloading
Gravitational equipotential surface model
- geodesyEarth measurement science
- gravimetryMeasuring gravitational field strength
Ductile upper mantle layer
- lithosphereCrust plus upper mantle
- viscosityFluid's flow resistance
- convectionHeat transfer via motion
- viscoelasticBoth liquid and solid-like
Geological mountain formation
- mountain buildingGeological uplift process
- subductionPlate descending beneath another
- erosionGradual wearing away
- sedimentationParticles settling in liquid
denudation · foreland basin · Himalayas · Alps · Andes
Thick glacial landmass covering
- deglaciationRetreat of glaciers
- sea level changeOceanic height variation
- loadingAdding weight or cargo
- unloadingRemoving contents from carrier
Hudson Bay · glacial lake · meltwater · ice mass · emergence
lithosphere
Crust plus upper mantle
- asthenosphereDuctile upper mantle layer
- compensationPayment for services rendered
- crustalOf outer rock layer
subsidence · uplift · flexure · earth's crust · topography · buoyancy · mass balance · loading · unloading · depression
geoid
Gravitational equipotential surface model
- geodesyEarth measurement science
- gravimetryMeasuring gravitational field strength
asthenosphere
Ductile upper mantle layer
- lithosphereCrust plus upper mantle
- viscosityFluid's flow resistance
- convectionHeat transfer via motion
orogeny
Geological mountain formation
- mountain buildingGeological uplift process
- subductionPlate descending beneath another
- erosionGradual wearing away
sedimentation · denudation · foreland basin · Himalayas · Alps · Andes
ice sheet
Thick glacial landmass covering
- deglaciationRetreat of glaciers
- sea level changeOceanic height variation
- loadingAdding weight or cargo
unloading · Hudson Bay · glacial lake · meltwater · ice mass · emergence