Thursday, August 21, 2008
When dating archaeological sites archaeologists usually radiocarbon date one of the houses in the village and assume all the other houses are the same age. Generally, archaeologists think of sites vertically rather than horizontally - they are used to digging down in one part of the site and finding older and older material as they get deeper into the site. They assume that people always chose to live in the same spot, and do not consider how a site varies horizontally.
We just got back the radiocarbon dates for our Karluk/O'Malley Lakes survey last May, and the dates confirmed that one of the big villages we found was actually 3 medium sized villages. While mapping the village we noted house style and construction details, and how lush the vegetation is on various parts of the site. Test pits help us with construction details (mostly whether or not a house had roof sods) and allow us to gather charcoal for our radiocarbon analysis. Sometimes we find 'neighborhoods' composed of houses built the same way and with similar style. The degree of vegetation lushness gives us an idea of how long ago that part of the site was occupied and/or how intensely it was used. Younger sites tend to have more lush vegetation, and the more you live in one spot, the more lush the vegetation. Last May we used this sort of analysis and decided that the biggest village we found was actually 3 villages. We even found a spot where one of the younger houses was built on top of an older house.
The radiocarbon dates not only confirm what we suspected but they also tell us how old the various neighborhoods are. At one end of the site a neighborhood of small, single-room houses, with lots of storage pits, roof sods over the main room and relatively little site vegetation was occupied at around 1000 AD. At the other end of the site people lived in a neighborhood, dated to around 1650 AD, of huge multiroom houses strung out in a line along the lakeshore - today these houses are surrounded by lush vegetation. In between the two neighborhoods we found another composed of small multiroom house associated with little site vegetation that lacked roof sods and generally had cold trap tunnels to the siderooms. This neighborhood dated to around 1400 AD.
Nearby we found another village that dates to around 1250 AD - so it looks like there was a large Alutiiq village near the head of Karluk Lake from about 900 to 1700 AD and that they moved their village every 200 years or so. For some reason they chose not to build their village in the same spot every time. Isn't radiocarbon analysis great!
Photos: Top - map of main village showing the various neighborhoods and their date of occupation. Bottom - Chase and Rose digging a test pit. If you look carefully you can see the roof sods they found over the floor of this house in the test pit wall profile. Patrick