1. Igneous rocks: These rocks are formed from the cooling and solidification of magma (molten rock) or lava (molten rock that has erupted onto the Earth's surface). Igneous rocks that originate deep within the Earth, such as those found in volcanic eruptions, provide clues about the composition of the mantle and possibly even the core. The minerals present in these rocks, and the way they are arranged, help scientists understand the pressure and temperature conditions at which they formed.
2. Metamorphic rocks: These rocks are formed when existing rocks (igneous, sedimentary, or even other metamorphic rocks) are transformed by heat and pressure. Metamorphic rocks often form deep within the Earth's crust, where they are subjected to the intense conditions associated with tectonic activity. They provide evidence about the conditions deep within the Earth's crust and can give us clues about the minerals present in the deeper mantle.
While these rocks provide valuable information, scientists also use other methods like seismic waves and meteorites to learn about the Earth's interior.
