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Frozen Isotopes

Frozen Isotopes. The water molecules in ice cores contain hydrogen and oxygen isotopes (frozen isotopes) used for dating the ice layers and the local temperature at the time. This study is not exactly accurate as isotopes diffuse with time. There are two main isotopes Oxygen-16 and Oxygen-18.

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Frozen Isotopes

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  1. Frozen Isotopes

  2. The water molecules in ice cores contain hydrogen and oxygen isotopes (frozen isotopes) used for dating the ice layers and the local temperature at the time. This study is not exactly accurate as isotopes diffuse with time.

  3. There are two main isotopes Oxygen-16 and Oxygen-18. Oxygen-18 is heavier. In warm temperature, Water molecules containing Oxygen-18 evaporate less readily and those containing Oxygen-16 condense more readily. In the winter, Oxygen-18 precipitates more readily, so more of it is found in the ice cores at the poles. Therefore the temperature can be measured depending on the variation in concentration of the two isotopes ( the Oxygen-18 to Oxygen-16 ration).

  4. There are two important isotopes in this area (10Be and 36Cl) • Both are produced by cosmic rays on the upper atmosphere, and their ions are charged in the Ionosphere. • The earth’s magnetic field traps their ions, causing a minor leakage to the lower atmosphere. • The amount of leakage depends on the height of the ionosphere, which depends on the solar cycle. ( The higher the solar activity, the bigger the height of the ionosphere). • By comparing the ratios of these isotopes with the non-radioactive isotopes ( 9Be and 35Cl), the temperature changes due to solar activity can be detected. • Disadvantage: Isotopes diffuse over time. Irradiation dependent markers

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