Re: measuring years through the Antarctica icesheets

> >How do scientists measure years through the Antarctica icesheets?

> There are yearly ice layers.  The melting in the summer creates a
> denser ice on the surface and thus one can count each year's
> accumulation, like leaves on a book.  I have seen photos of those
> layers but can't find one on the net.

There are also several seasonal chemical changes that can be traced in
an ice core. For example, the ratio of 18O to 16O varies with the
season. There are also some historical events that you can look for,
such as major volcanic eruptions or the high level of radionucleotides
associated with widespread atmospheric nuclear tests.

-- 
Dr. David Campbell
425 Scientific Collections Building
Department of Biological Sciences
Biodiversity and Systematics
University of Alabama, Box 870345
Tuscaloosa AL 35487-0345  USA