Lithosphere plastic deformation. The concept of the lithosphere as Earth’s strong outer layer was described by A.E.H. Love in his 1911 monograph "Some problems of Geodynamics" and further developed by Joseph Barrell, who wrote a series of papers about the concept and introduced the term "lithosphere". The concept was based on the presence of significant gravity anomalies over continental crust, from which he inferred that there must exist a strong, solid upper layer (which he called the lithosphere) above a weaker layer which could flow (which he called the asthenosphere). These ideas were expanded by Reginald Aldworth Daly in 1940 with
Geology of the Pacific Northwest spot, an extremely hot plume of deep mantle material, is rising to the surface beneath the Columbia Plateau Province. Geologists know that beneath Hawaii and Iceland, a temperature instability develops (for reasons not yet well understood) at the boundary between the core and mantle. The concentrated heat triggers a plume hundreds of kilometers in diameter that ascends directly through to the surface of the Earth. When the hot plume arrives at the base of the lithosphere, some of the lighter rock of the lithosphere rapidly melts. It is this molten lithosphere that becomes the basalt lavas that gush onto the