Geological dating

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Geological dating

  1. 1. Geological Dating
  2. 2. Relative Dating <ul><li>Relative dating is used to determine the age of something based on it’s position according to other things. </li></ul><ul><li>It tells if an object is older or younger than another object by using the Principle of Superposition. </li></ul>
  3. 3. Principle of Superposition <ul><li>This principle states that younger rock layers will be on top of older rock layers. </li></ul>
  4. 4. Absolute Dating <ul><li>Absolute dating is used by geologists to determine the actual age of a material. It can be achieved through the use of historical records and through the analysis of biological and geological patterns. </li></ul>
  5. 5. Radioactive Decay <ul><li>Naturally-occurring radioactive materials break down into other materials at known rates. </li></ul><ul><li>Each radioactive isotope has its own unique half-life . A half-life is the time it takes for half of the parent radioactive element to decay to a daughter product. </li></ul>
  6. 6. Geologic Column <ul><li>The geologic column is an ideal sequence of rock layers that contains all the known fossils and rock formations on Earth. </li></ul><ul><li>This is done by combining the information from all the known undisturbed rock sequences around the world. </li></ul>
  7. 7. Index Fossil <ul><li>Index Fossils lived during a relatively short but well-defined time span. This allows scientist to determine the age of the rocks these fossils are found in. </li></ul><ul><li>An example is a Phacops from the Trilobite genus. They lived 400 million years ago. So the rock layers they are found in can be dated at about 400 million years. </li></ul>
  8. 8. Trilobite
  9. 9. Types of Fossils <ul><li>True Form Fossils – Fossils of the actual animal or body part. </li></ul><ul><li>Mold Fossils – Fossils made of the imprint of the animal or body part. </li></ul><ul><li>Cast Fossils – Fossils from a mold that has been filled in. </li></ul><ul><li>Trace Fossils – Nests or gastroliths that were used by animals but not the animal itself. </li></ul>

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