A magma reservoir is a subterranean region containing partially molten silicates.
Understanding Magma Reservoirs
Magma reservoirs are found deep within the Earth's crust or upper mantle. They are not necessarily large, open caverns but can be complex networks of molten or partially molten rock dispersed within solid rock. As described by Lipman (2007), these regions are characterized by the presence of partially melted silicate material.
The Fate of Magma in Reservoirs
Once magma accumulates in a reservoir, it can follow one of two primary paths:
- Eruption: Some magma reservoirs serve as temporary holding places, often referred to as magma chambers. These chambers can be "staging areas for volcanic eruptions," where magma collects, evolves, and eventually ascends to the surface to erupt as lava, ash, and gases.
- Crystallization: However, the majority of magma reservoirs never reach Earth's surface (Lipman, 2007). Instead, the magma within these deeper reservoirs slowly cools and solidifies underground.
Here's a simple overview:
| Outcome | Description | Resulting Feature |
|---|---|---|
| Reaches Surface | Acts as a staging area for ascent and eruption | Volcanoes, Lava flows |
| Stays Underground | Cools and solidifies below the surface | Coarse-grained plutonic rocks |
When magma crystallizes underground, it forms intrusive igneous rocks. If the cooling is slow, it results in the formation of coarse-grained plutons, large bodies of solidified magma that are eventually exposed at the surface through erosion over geological time. Examples include granite or gabbro bodies.
In essence, while some magma reservoirs are directly linked to active volcanism (magma chambers), many others represent subsurface volumes where magma is generated and stored, ultimately solidifying without ever feeding an eruption.
