* Water lowers the melting point: Water acts as a flux, meaning it lowers the melting point of minerals. This is because water molecules disrupt the crystal structure of minerals, making it easier for them to melt.
* Pressure and water: At the high pressures found deep within the Earth, water can be dissolved into minerals. This dissolved water significantly lowers the melting point of the rock. This is a key process in the formation of magma in the Earth's crust.
Example:
* A dry granite might melt at around 1200°C (2192°F).
* A granite with water dissolved within its minerals might melt at around 800°C (1472°F) or even lower.
Important Notes:
* The specific melting point depends on the composition of the rock, the amount of water present, and the pressure.
* This effect is more pronounced at high pressures.
* The presence of other volatiles, like carbon dioxide, can also lower melting temperatures.
This lowering of the melting point due to water is a key process in the formation of magmas and volcanic eruptions.
