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asthenosphere Line breaks: as¦theno|sphere
Pronunciation: /əsˈθɛnəsfɪə/

Definition of asthenosphere in English:


The upper layer of the earth’s mantle, below the lithosphere, in which there is relatively low resistance to plastic flow and convection is thought to occur.
Example sentences
  • Because the downgoing slab of lithosphere is heavier than the plastic asthenosphere below, it tends to sink passively; and the older the lithosphere, the steeper the dip.
  • The models consist of a two-layered brittle-ductile system representing the overriding continental lithosphere, overlying a low-viscosity layer simulating the asthenosphere to provide isostatic support.
  • Scientists believe that below the lithosphere is a relatively narrow, mobile zone in the mantle called the asthenosphere.


Example sentences
  • They are interpreted to have been derived from subduction modified lithospheric and asthenospheric mantle sources.
  • We attribute the rapid return to subsidence in the basin to the confinement of abnormally hot asthenospheric mantle in the zone of continental break-up to the NW as sea-floor spreading commenced.
  • Given the lack of evidence for significant magmatism in the area, the likely heat sources are either radiogenic, or elevated heat flux from asthenospheric mantle emplaced at a relatively shallow level beneath the orogen.


Early 20th century: from Greek asthenēs 'weak' + sphere.

Definition of asthenosphere in:
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