The lithosphere formed as the Earth's surface cooled and solidified after a period of being a molten magma ocean.
The Formation Process
The Earth's early history involved a period where the planet's surface was a roiling ocean of molten magma. Over millions of years, this magma ocean began to cool.
Cooling and Solidification
- As the Earth cooled, the molten magma gradually solidified.
- This cooling process led to the formation of a solid crust on the planet's surface.
Formation of the Lithosphere
- The crust and the upper mantle together constitute what we know as the lithosphere.
- Initially, the lithosphere may have existed as a single, unbroken plate, similar to modern Venus, before breaking up into tectonic plates.
| Stage | Description |
|---|---|
| Molten Magma Ocean | Earth's early surface was entirely molten magma. |
| Cooling | The planet gradually cooled over millions of years. |
| Crust Formation | A solid crust began to form as the magma cooled and solidified. |
| Lithosphere Emergence | The crust and upper mantle combined to form the lithosphere. |
This process marks a significant transition from a molten planet to one with a solid outer shell, the lithosphere. The reference states, "Once the planet cooled enough for a crust to form, the surface may have looked more like modern-day Venus, with the crust and upper mantle — collectively called the lithosphere — forming a single unbroken plate."
