Crust Geology--In geology, a crust is the outermost layer of a planet. The crust of the Earth is composed of a great variety of igneous, metamorphic, and sedimentary rocks. The upper part of the mantle is composed mostly of peridotite, a rock denser than rocks common in the overlying crust.
Mantle-The mantle is a layer between the crust and the outer core. Earth's mantle is a silicate rocky shell with an average thickness of 2,886 kilometres (1,793 mi). The mantle makes up about 84% of Earth's volume. It is predominantly solid but in geological time it behaves as a very viscous fluid.
Outer Core-The outer core of the Earth is a fluid layer about 2,300 km (1,400 mi) thick and composed of mostly iron and nickel that lies above Earth's solid inner core and below its mantle. Its outer boundary lies 2,890 km (1,800 mi) beneath Earth's surface.
Inner Core-The Earth's inner core is the Earth's innermost part and according to seismological studies, it has been believed to be primarily a solid ball with a radius of about 1,220 kilometres (760 miles), which is about 70% of the Moon's radius. It is composed of an iron–nickel alloy and some light elements.
Continental Crust-the relatively thick part of the earth's crust that forms the large landmasses. It is generally older and more complex than the oceanic crust.
Oceanic Crust-Oceanic crust is the uppermost layer of the oceanic portion of a tectonic plate. The crust overlies the solidified and uppermost layer of the mantle. The crust and the solid mantle layer together constitute oceanic lithosphere.
Lithosphere-the rigid outer part of the earth, consisting of the crust and upper mantle.
Asthenosphere-the upper layer of the earth's mantle, below the lithosphere, in which there is relatively low resistance to plastic flow and convection is thought to occur.
Convection Currents in the Mantle-Convection currents in the magma drive plate tectonics. Heat generated from the radioactive decay of elements deep in the interior of the Earth creates magma (molten rock) in the aesthenosphere. The aesthenosphere (70 ~ 250 km) is part of the mantle, the middle sphere of the Earth that extends to 2900 km.
Ice Caps on the North and South Poles-Polar ice caps are dome-shaped sheets of ice found near the North and South Poles. They form because high-latitude polar regions receive less heat from the Sun than other areas on Earth. ... The polar ice caps contain the majority of Earth's supply of freshwater.