Sedimentary rock formation occurs when igneous, metamorphic, or other sedimentary rocks are exposed to the unyielding forces of nature found on the earth's surface. the formation of sedimentary rock occurs by several processes over millions of years. when rock sediments are deposited, an increase in weight causes pressure to increase which leads to the compaction of the rock particles. water is pushed out and cementation occurs as dissolved minerals are deposited in the very small spaces between the rock sediments acting as glue that binds the sediments together. which process describes the changing of sediments into rock by compaction and cementation? a) deposition b) lithification c) physical weathering d) chemical weathering