The Lithosphere

The lithosphere is the rigid out shell of earth, made out of the Crust and the upper part of the Mantle. The upper part of the Mantle has cooled enough to be brittle and stiff. The mantle under the lithosphere is solid, but can flow slowly like warm tar. The lithospere moves like a coherent block. These blocks are also called tectonic plates.

The thickness can vary, under the oceans is thinner (50-100 km) because it's constantly created at mid-ocean ridges. Under the continents it is thicker (150-250 km), because it has cooled and stabilized over billions of years.

Chemically, it is a mix of:

• Crustal material, silica-rich (continental) and Mafic (oceanic).
• The uppermost mantle, similar to Peridotite.

Question and Answers

What is the lithosphere?::Earth’s rigid outer shell consisting of the crust and the uppermost solid mantle.

Why does the lithosphere behave differently from the mantle below it?::It is cooler and more rigid.

What major geological parts make up the lithosphere?::The crust plus the uppermost mantle.

How thick is the lithosphere beneath oceans compared to continents?::Oceanic lithosphere is about 50–100 km thick; continental lithosphere is typically 150–250 km thick.

lithosphere:::the rigid outer shell of Earth made of crust and upper mantle