The top layer of the Earth is its crust which varies in age and thickness up to 48 miles thick in the mountains. An amazing fact about the crust is that even though there are 92 elements and over 3,500 minerals available that 94% of the crust is made up of only 6 elements. Oxygen 45%; Silicon 27%; Aluminum 8%; Iron 6%; Calcium 5% and Magnesium 3%.
All the rocks that one sees on Earth have been formed one of three ways.
Igneous rocks solidify from molten magma.
Sedimentary rocks form by the accumulation of particles in layers which are compressed and cemented together.
Metamorphic rocks are derived from other rocks through high temperatures and pressure.
The crust of the Earth in geological terms is divided into three different types:
1. Primary-solidification of the ocean (molten outer shell of the early Earth).
2. Secondary – formed from the heating and partial melting of planetary interiors known as lava basalts.
3. Tertiary – this type exists only on Earth because the Earth is the only planet with plate tectonics. The crust dives into the mantle and begins to heat up forming fluids. The fluids rise and melt part of the mantle. The melting mantle forms magma which is pushed to the surface and becomes part of the crust.
The face of the Earth is constantly in motion.
Did you ever sit and look at the moon and imagine that you could see a face because of the mountains on the moon and the way the sun light was hitting its surface? Now imagine sitting on the moon and looking at the Earth on a clear day on Earth and seeing if the Earth has a smiling face. Whatever our face looks like from a distant place it has changed expressions over time where as the moon is always smiling.