Explain the Types of sedimentary rocks?
What is a sedimentary rock? The word sedimentary is derived from the Latin word sedimentum which means "settling", which refers to a solid material settling out of a liquid. This is the case with the formation of many kinds of sedimentary rocks; for example, the oceans serve as the source of organic material to build up calcium carbonate sedimentary layers into limestone rocks. Not all sedimentary rocks form in a liquid. Some are from the remains of other rocks that become fused together within the Earth's subsurface pressures.
There are two main kinds of sedimentary rocks: detrital and chemical.
Detrital sedimentary rocks are rocks formed from the accumulation of materials that originate from, and are transported, as solid particles from mechanical or chemical weathering of other rocks. This means that sand and gravel that came together and were compressed into a rock would be a good example of a common detrital sedimentary rock. Sandstone is also a good example, as it is a collection of sand that has been pressed back into a soft rock.
Other examples of detrital sedimentary rocks are as follows: Shale is a rock formed from silt and clay sized particles that have been compressed together but not melted. Over half the known varieties of sedimentary rocks are shales, which can also hold underground reserves of the mineral fossil fuel oil. Sandstone is the name given to rocks in which sand sized particles predominate. Many patterns of the original environments can become preserved into sandstone sediments, including marine organisms, fossils, sand dunes, and moving water patterns. Conglomerates consist largely of rounded gravels that have been fused into a larger rock. Conglomerates form under high energy circumstances like rivers, steep mountain slopes, and wave activity. A breccia is a type of conglomerate with sharp edged stones inside it, as opposed to particles rounded from waver or river activity.
Chemical sedimentary rocks are formed from the processes of precipitation of dissolved chemicals from liquid into solid. Limestone is the most common chemical sedimentary rock. It accounts for about ten percent of all sedimentary rocks. Biochemical decomposition leads to the buildup of calcite (CaCO3) at the bottom of seas which grow into layered deposits, like the Cliffs of Dover in England.