sedimentary rock
Introduction
Sedimentary rocks are rocks that are formed by the accumulation of sediments, formed from particles of various sizes transported by water, ice or wind, which are subjected to physical and chemical processes (diagenesis), and which give rise to consolidated materials.[1] Sedimentary rocks can form on the banks of rivers, at the bottom of ravines "Ravine (geography)"), valleys, lakes, seas, and at the mouths of the rivers. They are arranged forming layers or strata.
There are external geological processes that act on pre-existing rocks; these agents weather them, transport them and deposit them in different places depending on the transport (water, wind, ice). Likewise, different animal or plant organisms can contribute to the formation of sedimentary rocks (fossils). Sedimentary rocks can exist up to a depth of ten kilometers in the Earth's crust. These rocks can present their constituent elements loose or consolidated, that is, they have been joined to each other by processes subsequent to sedimentation, known together as diagenesis.
Sedimentary rocks cover more than 75% of the Earth's surface, forming a sedimentary cover that is found on igneous rocks and,[2] to a lesser extent, on metamorphic rocks. However, their total volume is small when compared especially to igneous rocks, which not only form most of the crust, but also the entire mantle.[3][4].
The study of sedimentary rocks and rock strata provides information about the subsurface that is useful for civil engineering, for example in the construction of roads, houses, tunnels, canals "Canal (engineering)") or other structures. Sedimentary rocks are also important sources of natural resources, such as coal, fossil fuels, drinking water, and minerals.
The study of the sequence of sedimentary rock strata is the main source for understanding the History of the Earth, including paleogeography, paleoclimatology and the history of life. The scientific discipline that studies the properties and origin of sedimentary rocks is called sedimentology. Sedimentology is part of both geology and physical geography and partly overlaps with other disciplines of Earth sciences, such as Pedology, geomorphology, geochemistry and structural geology.
External geological processes
External geological processes such as weathering, erosion, transport and sedimentation act on the exposed rocks, caused by the environment or some organism, and causing the destruction of the relief. The first two processes wear down the rocks and break them into increasingly smaller fragments, known as clasts or debris, which are carried by rivers, wind or glaciers, to be deposited in sedimentary basins, normally the bottom of seas and lakes; There is a relationship between the size of the fragments and the distance it travels.