Formation of Intrusive and Extrusive Rocks
Formation of Intrusive Rocks:
- Magma Intrusion: Intrusive rocks are formed when magma cools and solidifies beneath the Earth's surface.
- Cooling Process: The slow cooling process of magma deep within the Earth allows for the formation of large crystals, giving intrusive rocks their coarse-grained texture.
- Examples: Common intrusive rocks include granite, diorite, and gabbro.
Formation of Extrusive Rocks:
- Lava Eruption: Extrusive rocks are formed when lava erupts onto the Earth's surface and cools quickly.
- Rapid Cooling: The rapid cooling of lava does not allow time for large crystals to form, resulting in fine-grained or glassy textures in extrusive rocks.
- Examples: Common extrusive rocks include basalt, andesite, and rhyolite.
In summary, intrusive rocks are formed from slow-cooling magma beneath the Earth's surface, leading to coarse-grained textures, while extrusive rocks are formed from rapid cooling lava on the Earth's surface, resulting in fine-grained or glassy textures.