Ice Core Dating

4/25/2012 archeology I. Methods of Dating Ice Cores Of the four-spot lucid method actings of dating the ages of ice cores the first three ar ground on direct experimental tests and the fourth rests on around questionable theories. Counting of Annual Layers The basis of this method lies with feel for items that vary with the seasons in a consistent manner. Of these atomic number 18 items that bet on the temperature (colder in the winter and warmer in the summer) and solar irradience (less irradience in winter and to a greater effect in summer). Once such markers of seasonal variations are found, they throne be used to bump the number of years that the ice-core put in over. This summons is analagous to the counting of direct rings. A major loss of these types of dating is that they are extremely condemnation consuming. Temperature Dependent Of the temperature dependent markers the some important is the symmetry of 18O to 16O. The urine molecules comp osed of H2(18O) mellow out less rapidly and narrow more readily indeed water molecules composed of H2(16O). Thus, water evaporating from the ocean it starts off H2(18O) poor. As the water vapor travels towards the poles it becomes more and more poorer in H2(18O) since the heavier molecules flow to precipitate out first.

This depletion is a temperature pendant process so in winter the precipitation is more enriched in H2(16O) than is the part in the summer. Thus, each annual degree starts 18O rich, becomes 18O poor, and ends up 18O rich. This process also depends on the relative temperatures of dis mistakab le years, which allows comparison with paleo! climatic data. For similar reasons the ratio of deuterium to hydrogen acts the alike way. The major prejudice of this dating method is that isotopes tend to broadcast as time proceeds. Irradiation Dependent Markers Of the irradiation dependent markers the two most important are 10Be and 36Cl. Both of these isotopes are produced by cosmic rays and solar irradiation impinging on the upper...If you want to bind a full essay, order it on our website: OrderCustomPaper.com

If you want to get a full essay, visit our page: write my paper