The Earth’s crust and its formation
Around 4.6 billion years ago, the sun, the Earth and the other planets in our solar system were formed from gas, dust, ice and rocky debris that condensed. Around 4.4 billion years ago, the first solid crust formed on Earth and the primordial oceans emerged. Since then, the distribution of land masses and oceans has constantly changed.
A distinction is made between oceanic and continental crust. While the continental crust is usually between 30 and 60 kilometers thick, the bottom of the deep sea consists of much thinner oceanic crust, about 6 kilometers thick.