Erosion, deposition, compaction, and cementation are the four major processes involved in the formation of sedimentary rocks. Erosion is the process by which weathered materials are transported from one place to another by wind, water, or ice. Deposition is the process by which these materials are deposited in a new location. Compaction is the process by which the deposited materials are pressed together by the weight of overlying sediments. Cementation is the process by which the grains of the deposited materials are bonded together by minerals such as calcite, silica, or iron oxide.