1. Plutons: These are large, irregularly shaped bodies of intrusive igneous rock. They can be classified into several sub-types:
* Batholiths: The largest type of pluton, often forming the core of mountain ranges.
* Stocks: Smaller, more localized versions of batholiths.
* Laccoliths: Lens-shaped intrusions that push overlying rock upwards, forming dome-shaped structures.
* Sills: Intrusions that are parallel to the existing rock layers, like flat sheets.
* Dikes: Intrusions that cut across existing rock layers, like vertical walls.
2. Other Structures:
* Veins: Narrow, tabular bodies of igneous rock that often contain valuable minerals.
* Pegmatites: Coarse-grained igneous rocks that form from the final stages of magma crystallization, often containing large crystals.
Examples of intrusive igneous rocks:
* Granite: A light-colored, coarse-grained rock often found in batholiths.
* Diorite: A medium-colored, coarse-grained rock that can be found in stocks and sills.
* Gabbro: A dark-colored, coarse-grained rock that can be found in dikes and laccoliths.
The specific structure that forms depends on the pressure and temperature of the magma, the composition of the surrounding rocks, and the rate at which the magma cools.
In summary:
Cooling and hardening of magma beneath the surface creates a variety of structures, including plutons (batholiths, stocks, laccoliths, sills, dikes), veins, and pegmatites. These structures are formed from intrusive igneous rocks such as granite, diorite, and gabbro.
