* Metamorphic rocks are formed when existing rocks (igneous, sedimentary, or other metamorphic rocks) are transformed by heat, pressure, and/or chemical reactions. They don't melt completely.
* Extrusive igneous rocks are formed when magma (molten rock) erupts onto the Earth's surface (extrusive) and cools and solidifies relatively quickly.
To go from metamorphic to extrusive igneous, the following would need to happen:
1. Melting: The metamorphic rock would need to be heated to a point where it melts completely. This would require extremely high temperatures, likely from a nearby magma source.
2. Eruption: The molten rock (now magma) would need to rise to the surface and erupt.
3. Cooling: The erupted magma would then cool and solidify quickly, forming an extrusive igneous rock.
In essence, the metamorphic rock would first need to become igneous through melting and then undergo an extrusive eruption to become an extrusive igneous rock.
