The earth’s crust is the outermost zone of the concentric structure of the geosphere. It is the outermost layer of rock. It is very thin with a thickness ranging from 5 km on the ocean floor to 70 km in active mountainous areas on the continents. The first crust on Earth was formed 4.5 billion years ago and its volume is not constant, scientists believe that it has increased over time.
There are two types of Earth’s crust:
Oceanic crust: Covers approximately 55% of the planet’s surface and has three levels. Most of it is located under the sea several thousand meters deep with certain exceptions such as Iceland and the Republic of Dijibouti.
Continental crust: It is less homogeneous than the oceanic. It is made up of rocks with diverse origins and has geologically active regions where tectonic and magmatic processes abound.
It is the solid surface layer of the Earth and is characterized by its rigidity. It is made up of the crust and the outermost part of the mantle and floats on the asthenosphere, a plastic layer that is part of the upper mantle.
It has a thickness of 50 to 100 km, its external limit being the terrestrial surface. It is divided into a series of tectonic plates whose edges concentrate phenomena such as seismicity, orogenesis and magmatism. Types of lithosphere:
- thermal lithosphere.
- seismic lithosphere.
- elastic lithosphere.
Differences between crust and lithosphere
- The lithosphere is the solid surface layer of the Earth and is rigid. It is made up of the crust and the outermost part of the mantle.
- The Earth’s crust is the outer rock layer of the Earth.
- The lithosphere is 50 to 100 km thick.
- The earth’s crust is 5 km to 70 km thick.