Thursday, September 23, 2010

More on rock pile half-life and site classification and chronology

Speaking (here) of damaged rock piles and estimating site age by the amount of the damage, or the proportion of damaged piles at the site (something I called rock pile half-life in these articles [you need to scroll down]), it is not such a crazy idea when construed statistically over a wide number of similar sites in a restricted region like east central Massachusetts. Take, for example, marker pile sites with triangular rock piles of which we have many examples, enough to comprise a legitimate statistical sample. And suppose, reasonably, that these are manifestations of a culture that existed in a limited part of the past - a time frame whose limits we want to estimate - or at least place in chronological order with other types of sites. It is certainly true that individual sites will have experienced different amounts of damage depending on later land use. If they were in an open field (I am thinking Manana Island) they might not get too quickly damaged. If they were subject to falling branches and trees, they might be more damaged. But over a large sample of sites the local differences in land use would average out in a restricted region. If you had a reasonable sample size for a different type of site, these same local variabilities would apply to them. To make a long story short: If over a collection of sites of one type there is more damage (on average) than for a collection sites of another type; then it is perfectly reasonable to conclude the more damaged sites are older. In this regard, there is no question that rock piles with hollows are significantly older than triangular rock piles.

I can almost create chronology now for these different types of rock piles:
  • piles with hollows and tails
  • piles with hollows and no tails
  • piles with hollows, no tails, and in proximity to "ski-jump" shaped piles, evenly spaced and in lines.
  • Evenly spaced triangular rock piles in lines and grids - with viewing platform or high point.
I like visual representations:For what it is worth these are also sort of regional:
  • Rock piles with hollows and tails (A) are from Carlisle to northern Fitchburg.
  • Rock piles with hollows and no tails (B) are from Leominster to Boylston to Hopkinton
  • Rock piles with hollows and outlying ski jumps (C) are from Upton to Holliston
  • Triangular rock piles (D) are pretty much everywhere.
I wonder how much of this is actually correct?


pwax said...

I am going to add a completely unscientific "narrative" backstory for this as a comment, since it has little legitimacy:

Rock piles with hollows represent a burial tradition that probably is an eastern version of mound building - so middle woodland time frame. The "tail" corresponds to a un-roofed portion of the pile where the body's remains were prepared before placement in the hollow. Later, preparation of the remains was done separately from the rock pile and the remains were placed in the hollow. Still later an astronomical function was added, using ski-jumps. Still later (late woodland to historic period) the burial function was gone and all that was left was the astronomical function of the triangular piles.

James Gage said...

The statistical proposal is intriguing. Any plans to test it? Judging by the number of sites mention in this blog for the Massachusetts region, you certainly have large enough sample size for such a test to be statistically meaningful. I also think statistical analysis can be applied to the distribution of different cairn designs regionally. It would be useful for distinguishing regional (geographic) differences from those caused by cultural changes and preferences over time (temporal).

James Gage

pwax said...

[Later, 2014] Good point James. Probably the whole network of relationships across space and across time will get a boost from dating technology. But I am glad you see the possibility of chronology without dating technology.