Plate theory (volcanism) in the context of "Decompression melting"

Play Trivia Questions online!

 or

Skip to study material about Plate theory (volcanism) in the context of "Decompression melting"
Ad spacer

⭐ Core Definition: Plate theory (volcanism)

The plate theory is a model of volcanism that attributes all volcanic activity on Earth, even that which appears superficially to be anomalous, to the operation of plate tectonics. According to the plate theory, the principal cause of volcanism is extension of the lithosphere. Extension of the lithosphere is a function of the lithospheric stress field. The global distribution of volcanic activity at a given time reflects the contemporaneous lithospheric stress field, and changes in the spatial and temporal distribution of volcanoes reflect changes in the stress field. The main factors governing the evolution of the stress field are:

  1. Changes in the configuration of plate boundaries.
  2. Vertical motions.
  3. Thermal contraction.

Lithospheric extension enables pre-existing melt in the crust and mantle to escape to the surface. If extension is severe and thins the lithosphere to the extent that the asthenosphere rises, then additional melt is produced by decompression upwelling.

↓ Menu

>>>PUT SHARE BUTTONS HERE<<<
In this Dossier

Plate theory (volcanism) in the context of Hotspot (geology)

In geology, hotspots (or hot spots) are volcanic locales thought to be fed by underlying mantle that is anomalously hot compared with the surrounding mantle. Examples include the Hawaii, Iceland, and Yellowstone hotspots. A hotspot's position on the Earth's surface is independent of tectonic plate boundaries, and so hotspots may create a chain of volcanoes as the plates move above them.

There are two hypotheses that attempt to explain their origins. One suggests that hotspots are due to mantle plumes that rise as thermal diapirs from the core–mantle boundary. The alternative plate theory is that the mantle source beneath a hotspot is not anomalously hot, rather the crust above is unusually weak or thin, so that lithospheric extension permits the passive rising of melt from shallow depths.

↑ Return to Menu
LINKED FROM (PARENTS)
← Hotspot (geology)
LINKS TO (CHILDREN)
Volcanism → Volcano → Plate tectonics → Lithosphere → Stress field → Plate boundaries → Magma → Crust (geology) → Mantle (geology) → Asthenosphere → Decompression melting →