Sedimentary rocks.pdf

Sedimentary rocks accumulated on the Earth surface through a process called deposition. Sedimentary rocks are combinations of the products of weathering and erosion, and organic materials. The process by which these unconsolidated are become, solidified into rock is called lithification when rocks...

Sedimentary rocks accumulated on the Earth surface through a process called deposition. Sedimentary rocks are combinations of the products of weathering and erosion, and organic materials. The process by which these unconsolidated are become, solidified into rock is called lithification when rocks or particles of soil or silt are carried from one location and placed in another, usually by moving water or wind. The wind or water can physically pick up and carry small particles, and these particles are deposited when there isn't enough energy to carry them any longer.  lithification is a geological process that transforms loose sediments into solid rock. It involves a series of physical and chemical changes that occur over time as sediments are buried and compacted.  Formation of sedimentary Rocks Sedimentary rocks are formed at or near the Earth’s surface by accumulation and lithification of fragments of pre-existing rocks or by precipitation from solution, at normal surface temperature. 1. Mechanically formed or Clastic rocks 2. Originally formed rocks 3. Chemically formed rocks  Mechanically formed or Clastic rocks Clastic rocks are defined as being composed of consolidated sediments formed by the accumulation of fragments derived from preexisting rocks and transported as separate particles to their places of deposition by purely mechanical agents. These fragments may be transported by water, wind, ice, or gravity. STEPS INVOLVED IN THE FORMATION OF CLASTIC ROCKS Decay and disintegration Hard coherent rock mass are gradually disintegrated and loosened. Such loosened materials accumulated near the source is called detritus. Transport of sediments Common transport like wind, running water and glaciers carry millions of tones of detritus to various places.  Gradual deposition The sediments which undergo grading according to their size, shape and density get deposited in layers under ordinary pressure and temperature conditions.  Diagenesis The process of transformation of sediments into cohesive, hard and massive rock because of compaction, consolidation and cementation is called diagenesis. Chemical Sedimentary Rocks Form by chemical precipitation that begins when water traveling through rock dissolves some of the minerals. These minerals are carried away from their source and eventually redeposited, or precipitated, when the water evaporates away.  Organic sedimentary rocks Form from the accumulation and lithification of organic debris, such as leaves, roots, and other plant or animal material. Rocks that were once swampy sediments or peat beds contain carbon and are black, soft, and fossiliferous. THANK YOU FOR LISTENING YMPSUG NTIHCRAEC TEAP EIGNLIT KLAHC EMILSTONE TMOIUUSBINC AOCL OELOSTOND QOUNICA FSEILOIRFSU MSOIENLTM