Rivers TRANSPORT broken rock. When rivers reach the sea, they DEPOSIT rock. The bits of rock SETTLE and build up in layers called SEDIMENTATION. The weight of the sediments squashes the sediment lower down. This is called COMPACTION. The water is squeezed out from between the pieces of rock and crystals of different salts form. The crystals form a sort of glue that sticks or cements the pieces of the rock together. This process is called CEMENTATION. These processes eventually make a type of rock called SEDIMENTARY rock. It may take MILLIONS of years for sedimentary rocks to form.
