Intrusive igneous rocks, also known as plutonic rocks, form when magma cools and solidifies beneath the Earth’s surface. This slow cooling process allows larger crystals to form, giving these rocks distinctive textures and appearances. Some common examples of intrusive igneous rocks include:
- Granite: A coarse-grained rock that is light in color and primarily composed of quartz, feldspar, and mica.
- Diorite: Similar to granite but darker in color, diorite contains a mix of feldspar, quartz, and darker minerals like hornblende.
- Gabbro: A dark, coarse-grained rock that is rich in iron and magnesium, predominantly composed of pyroxene and plagioclase.
- Peridotite: An ultra-mafic rock, rich in olivine and pyroxene, typically formed from the Earth’s mantle.
- Syenoite: A rock that is similar to granite but contains more nepheline and less quartz.
These examples highlight the diversity within intrusive igneous rocks, each with its unique mineral composition and texture, shaped by the conditions of their formation deep within the Earth.