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How does deposition lead to the formation of sedimentary rock?

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Faux amphibolite — geology A rock formation called “faux amphibolite,” from the Nuvvuagittuq greenstone belt in northern Quebec, dated to 4.28 billion years ago.

Deposition is a critical stage in the formation of sedimentary rock, serving as the process by which solid material—transported by water, wind, or ice—settles out of suspension or precipitates from a solution to accumulate as sediment.12

Once these loose grains or chemical precipitates accumulate, they undergo a complex conversion process known as lithification, which transforms the unconsolidated material into solid rock. This transformation typically involves several key mechanisms:31

Compaction: As layers of sediment accumulate, the weight of overlying material increases, causing grains to rearrange and pack more tightly together. This reduces pore space and expels interstitial fluids.34
Cementation: Minerals dissolved in groundwater precipitate into the remaining pore spaces, acting as a natural glue that binds the grains together.34
Authigenesis: Chemical reactions occurring within the sediment can lead to the formation of new minerals or the modification of existing ones, further strengthening the rock structure.3

While most sedimentary rocks form through this lithification of accumulated sediment, some chemical varieties, such as certain evaporites, precipitate directly into a solid form without an intervening stage as loose sediment.1