* Compaction is the process where the weight of overlying sediments squeezes out water and air from the spaces between sediment grains. This reduces the volume of the sediment and brings the grains closer together.
* Cementation is the process where dissolved minerals in groundwater precipitate out and crystallize in the spaces between sediment grains. These mineral crystals act like glue, binding the grains together and forming a solid rock.
Here's a simple analogy: Imagine building a sandcastle. The sand is like the sediment. When you pack the sand tightly, that's like compaction. When you add water to the sand and it dries, the water evaporates leaving behind minerals that solidify and hold the sand grains together, that's like cementation.
So, the answer to your question is cementation.
