Clastic Sedimentary Rocks

Clastic Sedimentary rocks are formed through the compaction and cementation of the weathered remains of other rocks. Compaction occurs when pressure, caused by the weight of overlying sediment, causes sediment grains to become more closely packed and reduces pore spaces between the sediment. Finer material that may have resulted from pulverizing original sediments then fills these pore spaces and binds the rock. This finer material is called the matrix.

Cementation occurs when minerals that have been dissolved in water begin precipitating within the pore spaces of sediments. Common cements include: quartz (SiO2), calcium carbonate (CaCO3), and hematite (Fe2O3). The acid test can be used to determine whether or not a rock has been cemented by calcium carbonate. Hematite cement will typically result in a rust-colored sedimentary rock.

Clastic Sedimentary rocks are further categorized based on rounding and sorting of clasts