Final answer:
The process that turns loose sediment into rock, called lithification, involves two main steps: compaction and cementation, where sediment grains are pressed together and cemented by minerals like calcite, quartz, and pyrite.
Step-by-step explanation:
The process via which loose sediment is transformed into rock is called lithification. This process encompasses two main steps: compaction and cementation.
Compaction occurs as layers of sediment are deposited on top of one another, reducing the porosity by squeezing the sediment grains closer together, much like compressing trash in a garbage bin. Cementation then follows, where minerals precipitate out of water being squeezed from pores during compaction, and these minerals act as a glue to bind the sediment grains together, forming sedimentary rock.
Key minerals that often contribute to the cement that binds sediment grains include calcite, quartz, and pyrite. Sedimentary rocks are formed from particles carried and deposited by water or air, or chemicals precipitated from water. These processes are fundamentally different from the mechanisms that form igneous and metamorphic rocks. For example, igneous rocks are created when magma cools, while metamorphic rocks are formed by the alteration of pre-existing rocks under heat and pressure without melting.