Silica and Magnesium
Explanation
The Earth's crust is the outermost solid shell of the planet, categorized into continental and oceanic crust based on composition, density, and thickness.
- Oceanic Crust (SIMA): The oceanic crust is thinner (5–10 km) and denser than the continental crust. It is primarily composed of Silica and Magnesium. Due to these dominant constituents, it is often referred to as SIMA. It is largely basaltic in nature.
- Continental Crust (SIAL): The continental crust is thicker and less dense. It mainly consists of Silica and Alumina, leading to the acronym SIAL. It is largely granitic in nature.
- Core (NIFE): The core of the Earth is composed primarily of heavy metals, specifically Nickel and Iron, referred to as NIFE.
Key Takeaway: The oceanic crust is characterized by the composition of Silica and Magnesium (SIMA), whereas the continental crust is characterized by Silica and Alumina (SIAL).