Sometimes I think it is hopeless to imagine dating rock piles. But it might be possible to put different sites into some kind of chronological order even if we are not sure when they were individually built - not sure how to calibrate the scale. We might aim for saying thing like "this site is older than that one". But we still need a metric to decide what to believe.
So how about a concept of site"half life" - a claim of the form "50% of the piles at a site will be badly damaged after 100 years." So if there are two sites, everything else being equal, the site with more intact rock piles is judged to be younger. Also, if you believe the rule, a site with more than 50% of its piles being intact is judged to be younger than 100. [For example, the outcrop site from Groton [Click here] I reported last week has about 5 of 10 rockpiles still nearly intact. Artifacts found nearby are probably less than 100 years old.]
It is an interesting exercise. How useful is it? It helps to focus on the forces which damage rock piles. Unless there is good reason to believe one location was more badly damaged than another - one more harshly used, then comparing site ages by the amount of damage is reasonable.