Lecture 25-26 Earth's Structure(1)

L this implied that just below the lithosphere the

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: – the solid layer of a planet i.e. the surface crust and a small porHon of the mantle 0 to 80km l༆  Asthenoshere – the plasHc (deformable) upper layer of the mantle 80 to 200km How are Mountains Supported then? 36 l༆  There are porHons of the Earth’s crust that sHck quite far out and weigh a tremendous amount. l༆  If the Earth’s surface is like a “thin crust pizza” and the region under it is deformable, then how can it support a mountain (equivalent to a case of beer on top of the thin crust pizza)? l༆  The answer lies in concepts that you learned around lecture # 8; i.e. buoyancy 37 l༆  Because of layering effects the most dense materials go to the booom and the lighter ones stay on top. l༆  The Earth’s crust is made up of the least dense material l༆  The idea of a deformable layer, called the asthenosphere, upon which large secHons of crust could “surf” is certainly consistent with conHnental drii, but why don’t massive structures like the Himalayan mountains sink? l༆  Because the material that they are made of is the l...
View Full Document

Ask a homework question - tutors are online