Rocks are heavy: transportation costs and Paleoarchaic quarry behavior in the Great Basin
Citation: Charlotte Beck, Amanda K. Taylor, George T. Jones, Cynthia M. Fadem, Caitlyn R. Cook, Sara A. Millward (2002) Rocks are heavy: transportation costs and Paleoarchaic quarry behavior in the Great Basin. Journal of Anthropological Archaeology (RSS)
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Tagged: lithic analysis (RSS), central place foraging model (RSS), resource procurement (RSS)
Summary
Context:
This article is a very in-depth look at, and discussion of adapting principles of optimal foraging theory to lithic assemblage analysis. Specifically, the researchers are looking to discover at what distances it makes more sense for Paleoarchaic knappers to reduce bifaces preforms to what extent. They do this following the theory of central place foraging, wherein it is theorized that certain resources will be reduced to their most important(i.e., usable) constituent parts before being transported, based on how far from a central camp the resources are gathered.
Method:
In order to apply this theory the authors need a staggering amount of data. First, are sites from which to analyze lithic artefacts of which four are chosen: a pair of quarry sites and a pair of habitation sites. The first pair is Cowboy Rest Creek Quarry and the Knudtsen site. These two sites are approximately 9 kilometers apart. Next is the Little Smokey Quarry and the Limtestone Peak site which are 60 kilometers apart from one another. These sites were chosen in order to help the authors control numerous variables that could potentially confound their research. The vast majority of the artefacts from the two habitation sites are made from dacite from the quarries that are associated with them, also both sites are identified as belonging to roughly the same Paleoarchaic tool tradition known for producing stemmed bifacial artefacts. This variable control and the absolutely enormous number of artefacts at all four sites allows the researchers to perform statistical analysis to help answer their research question.
In addition to the sites, control processes and large numbers of data points, the authors chose to use a method to identify the stage of reduction that each biface found in the quarry was at. Using a 0-3 scale ranging from being a general, irregular bifacial shape at 0, to being an almost finished biface at 3, will allow an almost categorical study to be made. As a potential optional way to measure stage of retouch, they also use the Johnston Thinning Index which is based on flake mass and area of the flake in plan view. The intent with the JTI is that the thinner the stone is the less it will weigh, but as it is reduced it loses mostly mass, thickness and width but not length, leaving a higher relative area in plan view, with a greatly reduced weight. And finally, the authors use the mathematic Central Place Foraging Model, which posits that distance between source and habitation increases, the more energy efficient it is to process these resources in the field. The model is a function of a resources Utility(U) and the increased utility of resource after processing which has a time cost(t). This function when graphed against processing time x, transport time z and a measure of its utility y, then provides a slope to discern a resources value based on distance and difficulty of procurement and processing.
Results:
The researchers define their hypothesis simply: the farther that a group must travel to procure their lithic resources, the more reduction of that material will be visible in the archaeological record. After producing their means for the JTI, and their contiguous 0-3 model of reduction and comparing the four sites statistically though simple T-Tests and K-S tests, what they discovered was that at Little Smokey Quarry the bifaces in the assemblage were considerably more reduced by both measures. Their data clearly shows that the farther a lithic resource must travel to a “central place” or habitation site, the more likely it will be field processed before that journey is made.
Theoretical and Practical Relevance
Another way to think of this model is in terms of risk as well as energy. Thinking back to Robin Torrence’s piece, “Retooling: towards a behavioral theory of stone tools”, the distance involved in at least one of these procurement runs is approximately 60 kilometers a relatively enormous distance for a group to travel to acquire any resources if they are then returning to a habitation site. These journeys were not only long, but dangerous would not be undertaken if the maximum amount of usable resources could not be acquired during the process. Therefor it may not be the distance alone that drives the field reduction process, but the risk-reward factor of the trip itself.
This is a thoroughly well researched and tested paper, and it is always fascinating when statistical and mathematical modeling can be used to test any archeological theory. In the end, a more streamlined approach may have been possible, but their thoroughness only adds to the weight of their research.
