The Lithosphere
(rock)
The word lithosphere is derived from the word sphere,
combined with the Greek word lithos, meaning rock.
The lithosphere is made up of all the hard and solid land mass on the earth’s surface, the semi-solid rocks (molten materials) underneath the earth crust, and the liquid rocks in the inner core of the earth.
The surface of the lithosphere is uneven as it is characterized by various landform features. Some of the landforms include mountains, deep valleys, mountain ranges, huge plains and extensive plateaus.
The liquid, semi-solid, and solid land components of the lithosphere form layers that are chemically and physically different. This is why the lithosphere is further divided into sub-spheres namely the crust, the mantle, the outer core, and the inner core. The crust is made of loose soil and rocks. The mantle is made of dense rock made up of nickel and iron in the form of silicate rocks and its lower part is semi-solid (partially molten) rocks.
The outer core is made up of liquid (purely molten) rock materials. The inner core is the centre of the earth which is purely made of very hot and liquid iron and nickel. The rock materials are divided into three primary categories based on how they are formed namely igneous rocks, sedimentary rocks, and metamorphic rocks.
The lithosphere is subdivided into tectonic plates.
The lithosphere is underlain by the asthenosphere which is the weaker, hotter, and deeper part of the upper mantle.
