You searched for: “petrosphere
lithosphere, petrosphere
The brittle outer part of the earth, consisting of the crust and the upper mantle.

It is made up of six major and several minor tectonic plates that move around on the softer asthenosphere or the relatively plastic layer of the upper mantle of the earth on which the tectonic plates of the lithosphere move.

It is about 55 km (34 mi) thick beneath the oceans and up to about 200 km (124 mi) thick beneath the continents and is composed of rigid plates.

The high velocity with which seismic waves propagate through the lithosphere suggests that it is completely solid.

The movement of the plates of the lithosphere results in convergence, or collisions, that can form mountain belts and subduction zones, and divergence of the plates and the creation of new crust as material wells up from below separating plates. The lithosphere and asthenosphere are distinguished from the crust, mantle and core of the earth on the basis of their mechanical behavior and not their composition.

petrosphere (s) (noun), petrospheres (pl)
In archaeology, the name for any spherical man-made object of any size that is composed of stone: These petrospheres are primarily prehistoric artistic objects which may have been created and/or selected, but altered in some way to perform their specific functions, including carving and painting.

This entry is located in the following units: petro-, petr-, petri-, peter- (page 5) sphero-, spher-, -sphere- (page 10)