Continental plates are primarily made of granitic rocks. These rocks are composed of lighter minerals, which makes the continental crust less dense than oceanic crust.
Composition of Continental Crust
The primary component of continental crust is granitic rock. This type of rock is characterized by its relatively low density. This low density is because of the minerals that make up granite.
Key Minerals in Granitic Rocks
- Quartz: A hard, crystalline mineral composed of silicon and oxygen.
- Feldspar: A group of rock-forming minerals containing aluminum, silicon, and oxygen, along with other elements.
These minerals are lighter compared to the basaltic rocks that form the oceanic crust. This difference in density is a key factor in why continental crust floats higher on the Earth's mantle than oceanic crust.
Comparison with Oceanic Crust
| Feature | Continental Crust | Oceanic Crust |
|---|---|---|
| Rock Type | Granitic Rocks | Basaltic Rocks |
| Density | Less Dense | Denser |
| Mineral Composition | Quartz and Feldspar | Other heavier minerals |
According to the reference, continental crust is made up of relatively lightweight minerals such as quartz and feldspar, while oceanic crust is composed of much denser and heavier basaltic rocks.
