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Glite Dictionary
asthenosphere

asthenosphere

1 9.9
A soft, partly melted layer under the Earth's hard outer rock that lets tectonic plates move
  • noun
  • /æˈsθɛnəˌsfɪr/
  • Specialized
: astenósfera
  • The tectonic plates move on the semi-fluid asthenosphere beneath the Earth's lithosphere.

Examples

  • Convection currents within the asthenosphere help drive the movement of the tectonic plates.

  • If two plates are composed of dense oceanic crust, one plate will be subducted, pushed down into the asthenosphere.

    Academic text (1995)

  • Large rigid plates are created at divergent boundaries, glide along on an underlying fluid asthenosphere, and descend at convergent boundaries.

    Academic text (1995)

  • Scientists study the asthenosphere to understand how it influences geological activity on Earth.

Surface Forms

asthenosphere singular
asthenospheres plural

Morphology

asthenosphere = sphere (semi-transparent) = astheno + sphere

The combining form 'astheno-' is a rare Greek medical/geological combining form unlikely to be known by B1 learners, but 'sphere' signals a zonal layer so the meaning is partially inferable.

Etymology

Asthenosphere comes from two Greek parts: astheno- meaning 'weak' and -sphere meaning 'ball' or 'layer', as in atmosphere. So it means a 'weak layer' of the Earth that is soft enough to let tectonic plates move.