5.3 Clastic Sedimentary Rocks
Clastic Sedimentary Rocks
Now that you are familiar with the type of clasts that form after a rock is weathered, we will examine the sedimentary rocks that form when these clasts undergo lithification, the process of sediments forming rocks. Clastic sedimentary rocks are rocks that are formed when sedimentary clasts are deposited and become cemented or compacted together.
Over time, as more sediment and rock is deposited, the lithified rock undergoes diagenesis, which is a process in which low amounts of pressure and temperature are applied to the rock to cause physical and chemical changes to the deposit. This mostly causes loose sediment to become solid rock.
Some common clastic sedimentary rocks include the following:
Conglomerate: Consists of rounded pebbles and/or cobbles.
Breccia: Consists or angular pebbles or cobbles.
Sandstone: Consists of sand-sized grains. Although the individual grains are small, they are still visible to the naked eye.
Shale: Smooth, and consists of mud, and sometimes breaks into thin plates. The individual grains are not visible to the naked eye.
Let’s Review!
Using the definitions above, view the videos of clastic rocks and assign each the appropriate rock name.
