Question

When rocks melt, what kind of rocks do they become? How does this happen?

Answer 1

Igneous rocks (generally), due to high temperatures.

Explanation:

When a rock melts, it isn't a rock anymore, it's magma (if it's beneath the surface) or lava (above the earth's surface). The melting occurs as a result of high temperatures, which almost always occur below the surface of the earth - making it magma.

Basalt, for example, has a melting point of `984^o` C to `1260^o` C, according to American Mineralogist. Basalt is the primary rock type that makes up the oceanic crust, and it commonly subducts beneath its less dense intrusive cousin, granite, the primary rock type that makes up the continental crust. Because of this subduction, it eventually ends up closer to the earth's core where it's hot enough to cause the solid to liquefy, creating magma.

The magma isn't considered a rock until it crystallizes, but when it does crystallize (AKA freeze, which happens both above and below the surface of the earth), it's called an igneous rock. Igneous translates to "from fire," so it's fairly easy to remember where it comes from.