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.
- 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.
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