Delamination (geology)

In geodynamics, delamination refers to the loss and sinking (foundering) of the portion of the lowermost lithosphere from the tectonic plate to which it was attached.

This limits this phenomenon to arc environments, volcanic rifted margins and continental areas undergoing extension.

Second, flow of hot mantle material encounters the base of the thin lithosphere and often results in melting and a new phase of volcanism.

Observations which support delamination include sudden mafic volcanism and acceleration of uplift, occurring 14 to 11 Ma.

Some researchers postulate that the Sierra Nevada (California), Basin and Range Province and Colorado Plateau in the western US exemplify this.

[3] One example of the effects of lithosphere delamination is seen in the Sierra Nevada (US)², Basin and Range Province and Colorado Plateau in the western USA.

[3] During crustal extension in the Basin and Range Province 10 million years ago, the upwelling of asthenosphere thinned the lithosphere.

Heating caused by the rise of the warmer asthenosphere created a crustal lower-viscosity zone and delamination occurred on the flanks of the Basin and Range.

Uplift of the Sierra Nevada mountain range in California and the Colorado Plateau has occurred on the flanks as a result of the loss of high density lower lithosphere.

California's Sierra Nevada Mountains (formed by delamination) as seen from the International Space Station . When a large portion of dense materials was removed under the tectonic plate at this location, the remaining portion of the crust and lithosphere underwent a rapid uplift forming this mountain range.