Mining companies have technology that can detect rock formations underneath Earth’s outer layer. One mining company detects an igneous rock formation underneath Earth’s outer layer. The geologists working for the company wonder if material in this igneous rock used to be sedimentary rock at Earth’s surface. Can material in sedimentary rock become igneous rock? Explain your answer.

Answer 1

Yes, material in sedimentary rock can indeed become igneous rock through a process known as the rock cycle. Here's how this process can occur:

1. Weathering and Erosion: Sedimentary rocks are formed from particles (sediments) that have been weathered and eroded from pre-existing rocks (including igneous and metamorphic rocks) and then compacted and cemented over time.

2. Subduction and Metamorphism: At tectonic plate boundaries, sedimentary rocks can be pushed down into the Earth’s crust where they may experience increased pressure and temperature. This can lead to the metamorphism of sedimentary rocks, transforming them into metamorphic rocks.

3. Melting: If the conditions intensify (such as further increasing temperatures or pressures), the metamorphic rocks—or even the sedimentary rocks themselves—can melt into magma.

4. Cooling and Solidification: When this magma rises to the surface or cools at depth (such as in a volcanic or plutonic setting), it solidifies to form igneous rock.

Therefore, while sedimentary rocks do not directly turn into igneous rocks, the material that was once sedimentary can ultimately become igneous through the processes of metamorphism and melting, followed by cooling and solidification.