Final answer:
Igneous rock formed below the Earth's surface can be uplifted through tectonic forces, then broken down into sediments that lithify into sedimentary rock. Subduction can carry sedimentary rocks back down into the mantle, potentially transforming them into metamorphic rocks instead of melting them.
Step-by-step explanation:
To understand how an igneous rock formed below Earth's surface can transform into a sedimentary rock, we need to consider the geological processes of uplift and subduction. These processes are part of the rock cycle, which is driven by plate tectonics. Initially, an igneous rock is formed by the cooling and solidification of magma beneath the Earth's surface. Over time, tectonic forces can cause this rock to be uplifted to the Earth's surface. Once at the surface, weathering and erosion break down the rock into sediments.
These sediments can be transported by wind, water, or ice, and eventually deposited in layers. Over long periods, the accumulated sediment is subjected to pressure, and with the addition of minerals acting as cement, these layers can lithify to become sedimentary rock. However, if the sedimentary rock becomes part of a tectonic plate that is being subducted, it can be carried back down into the Earth's mantle. If the conditions are not extreme enough for it to melt and form new igneous rock, it might undergo high-pressure and low-temperature conditions that can transform it into a metamorphic rock instead of melting.
Thus, through the dynamic processes of uplift and subduction, igneous rocks are reshaped into sedimentary rocks, illustrating the Earth's ongoing and complex geological cycle.