As streams flow through Stone Mountain, layers of sand build up. Over time, the sand particles form a sedimentary rock called sandstone. What causes sandstone to change into metamorphic rock at Stone Mountain? Sandstone is reshaped by erosion from a stream. Sandstone builds up layers of sand at the mountain. Sandstone experiences intense heat and pressure. Sandstone has more sand particles compacted on top of it.
The reason that causes the sandstone to turn into a metamorphic rock is that it experiences extreme heat and pressure.
Explanation:
When the process of sedimentation occurs due to the accumulation of sand for a "long period of time", the layers that were once at the top get buried deep under the overlaying layers of sand.
This initially results in the sedimentary rocks formation at the bottom of this accumulation.
Over time, the sedimentary rock at the bottom is subjected to extreme pressure and heat from above.
The action of extreme pressure and heat on the sedimentary rock converts it into a metamorphic rock.