Oxygen isotope dating

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What were temperatures like during the last ice age?How was vegetation distributed across North America during the late Wisconsin glaciation?So, because different isotopes of the same element have different weights, they behave differently in nature.Oxygen has three different isotopes: oxygen 16, oxygen 17 and oxygen 18.Evaporation selectively removes the lighter isotope, O-16 from water leaving higher concentrations of the heavier isotope, O-18.Thus, shells and other materials formed in the ocean tend to have more O-18 during colder, glacial intervals than during warmer intervals.Isotopes of single elements possess almost identical chemical properties.

The main driver of the evaporation effect in most geological intervals is the amount of water that has been removed from the ocean and is sequestered in ice (see video clips below).Naturally, the inaugural question in any study such as this is the one regarding definition. " One of the better extant definitions is that proffered by the INEEL Environment Surveillance, Education, and Research Program of the Idaho National Laboratory.The INEEL defines isotopes as, "Two or more forms of an element having the same number of protons in the nucleus (or the same atomic number), but having different numbers of neutrons in the nucleus (or different atomic weights).However, as a portion of the evaporate ends up falling as snow which is then converted to ice, the reverse holds for ice sheets, such as those in Greenland and Antarctica.Ice formed in glacial intervals has more O-16 than ice grown in warmer times.

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