Noun
the lower layer of the crust
Source: WordNetA third type of basin exists along convergent plate boundaries - places where one tectonic plate moves under another into the asthenosphere. Source: Internet
Mechanically, the lithosphere is cooler and more rigid, while the asthenosphere is hotter and flows more easily. Source: Internet
The greater density of old lithosphere relative to the underlying asthenosphere allows it to sink into the deep mantle at subduction zones, providing most of the driving force for plate movement. Source: Internet
Top: delamination by intrusion of hot asthenosphere ; Bottom: Subduction of ocean crust. Source: Internet