Sedimentary Rocks 2011 copyright


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Sediments to sedimentary rocks. A natural process on Earth because of weathering and erosion.

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Sedimentary Rocks 2011 copyright

  1. 1. Sedimentary Rocks by Ann C. Cloutier 2011 copyright
  2. 2. Sediments are pieces of solid material that have been deposited on Earth’s surface by wind, water, ice, gravity or chemical precipitation <ul><li>Large rock structures go through erosion and weathering producing sediments that later may form into sedimentary rocks </li></ul><ul><li>When sediments become cemented together they form sedimentary rocks </li></ul>acloutier copyright 2011
  3. 3. Weathering of Earth’s surface acloutier copyright 2011
  4. 4. Types of weathering of rocks <ul><li>Physical and chemical processes break rocks down into smaller pieces </li></ul><ul><li>Chemical weathering breaks down minerals in the rock by dissolving and chemically changing the minerals into other compounds and elements </li></ul>acloutier copyright 2011
  5. 5. Resistant mineral grains are released and weaker grains are broken down in the process of chemical weathering <ul><li>Once an active volcano, now just the neck of the volcano has survived chemical erosion </li></ul>acloutier copyright 2011
  6. 6. Many types of erosion can affect a surface area of Earth’s lithosphere acloutier copyright 2011
  7. 7. Four major agents of erosion <ul><li>wind </li></ul><ul><li>moving water </li></ul><ul><li>gravity </li></ul><ul><li>glaciers </li></ul>acloutier copyright 2011
  8. 8. A glacier carved this landscape millions of years ago acloutier copyright 2011
  9. 9. Deposition is the laying down of sediments on the ground or that sink to the bottom of bodies of water like the oceans or lakes <ul><li>sediments are transported by the wind, water movement ,glaciers and gravity </li></ul><ul><li>once transportation of sediments stop, deposition occurs. </li></ul><ul><li>as more and more sediments pile up on top of each other, lithification occurs </li></ul><ul><li>Lithification is the physical and chemical process that transforms sediments into sedimentary rocks </li></ul><ul><li>Lithification begins with compaction </li></ul>acloutier copyright 2011
  10. 10. Cementation occurs when mineral growth cements sediment grains together into solid rock <ul><li>Two types of cementation : </li></ul><ul><li>Calcite Ca CO 3 </li></ul><ul><li>Iron oxide Fe 2 O </li></ul>acloutier copyright 2011
  11. 11. Cross-bedding is formed as inclined (slope) layers of sediments move forward across a horizontal surface acloutier copyright 2011
  12. 12. Graded Bedding is where the particle size of sediments becomes progressively heavier and coarser towards the bottom layers acloutier copyright 2011
  13. 13. Fossils are found in sedimentary rocks ! <ul><li>Fossils are the preserved remains, impressions, or any other evidence of once-living organisms </li></ul><ul><li>During lithification (burying) parts of the organism can be replaced by minerals and turned into rock </li></ul>acloutier copyright 2011
  14. 14. Chemical sedimentary rocks <ul><li>evaporites </li></ul><ul><li>mostly form in arid areas, oceans, and drainage basins </li></ul><ul><li>the water content evaporates </li></ul><ul><li>stalactite & stalagmite </li></ul><ul><li>> formed in caves by dripping water </li></ul>acloutier copyright 2011
  15. 15. Three types of sedimentary rocks <ul><li>Chemical > limestone, travertine, rock salt, gypsum </li></ul><ul><li>Organic > limestone, coal </li></ul><ul><li>Clastic > conglomerate breccia , sandstone, shale </li></ul>
  16. 16. Organic > once alive acloutier copyright 2011acloutier copyright 2011
  17. 17. Clastic <ul><li>Clastic comes from the Greek word “klastos” meaning broken </li></ul><ul><li>Worn edges usually </li></ul><ul><li>Sizes of clastic rocks range from large conglomerate (boulder,cobbles,pebbles) to gravel </li></ul><ul><li>265mm – 2mm particle sizes </li></ul>acloutier copyright 2011
  18. 18. ENERGY from sedimentary rocks <ul><li>Coal </li></ul><ul><li>Oil </li></ul><ul><li>Natural gas </li></ul><ul><li>Uranium </li></ul><ul><li>is often mined from sandstone, sedimentary rock </li></ul>
  19. 19. The end