The correct option is Differentiation
Explanation
The internal structure of the Earth is divided into distinct layers (crust, mantle, and core) based on physical and chemical properties. The geological process responsible for this separation during the planet's formative years is known as differentiation.
Detailed Analysis:
- Accretion Accretion (Incorrect): Accretion is the initial process by which dust, gas, and planetesimals came together under gravity to form the primordial Earth. While it increased the Earth's mass and heat, it refers to the accumulation of material, not its subsequent separation into layers.
- Differentiation Differentiation (Correct): As the primordial Earth melted due to heat from accretion and radioactive decay, materials separated according to their density. Heavier, high-density elements like iron and nickel sank towards the center to form the Core, while lighter, lower-density silicate materials floated upward to form the Mantle and Crust. This density-based stratification is the defining characteristic of planetary differentiation.
- Degassing Degassing (Incorrect): Degassing is the process by which gases (such as water vapor, carbon dioxide, and nitrogen) were released from the Earth's interior through volcanic activity. This process was responsible for the formation of the primordial atmosphere and hydrosphere, not the solid interior layers.
- Condensation Condensation (Incorrect): Condensation refers to the change of state from gas to liquid or solid. In the context of the solar system's formation, it explains how solid grains formed from the solar nebula, but it does not explain the internal layering of the formed planet.
Key Takeaway:
Differentiation is the process by which Earth's forming material separated into concentric layers (Crust, Mantle, Core) based on density, with heavier elements sinking to the center and lighter elements rising to the surface.