Radioactive dating in antartic
The amount of "leakage" depends on the height of the ionosophere, which changes primarily in response to the Solar cycle, with periods of maximum solar activity corresponding to the highest extent of the ionosphere.It should be noted that the 10Be/9Be ratios for some ice cores have been compared with the known solar cycle and are in excellent agreement with what is known (accurately showing the time of the European Little Ice Age, which corresponded with a remarkably low amount of solar activity). Of these are items that depend on the temperature (colder in the winter and warmer in the summer) and solar irradience (less irradience in winter and more in summer). The basis of this method lies with looking for items that vary with the seasons in a consistent manner.
Of the irradiation dependent markers the two most important are 10Be and 36Cl. 9Be and 35Cl) one can determine the season of the year the precipitation occurred. By comparing the ratios of these isotopes to their nonradioactive counterparts (i.e.Examples of such inclusions are a decrease (or increase) in temperature over a period of years that can be determined from flora and fauna found in the oceanic core and a decrease (increase) in the 18O enrichment over this same period of years. These are the primary "inclusions" that are compared.I apologize for my use of nondescript terminology here.