Toolstone constraints on knapping skill: Levallois reduction with two different raw materials

Lithic raw material constraints are widely assumed to be a determining factor of flaked stone tool morphology, but this assumption remains largely untested. We conducted a controlled experiment to determine whether a knapper’s growing replication skills would be hindered if the toolstone used was switched from large flakes of an easily worked chert to nodules of less tractable one. Two batches of Preferential Levallois cores were knapped, an earlier series made from standardised large flakes of sediments dominated by chalcedonic quartz followed by a more challenging one using variably-shaped, cortical nodules of microcrystaline quartz that varies in the completeness of quartz replacement of calcite and dolomite. Skill level markers were designed to measure the knapper’s ability to achieve a series of set goals. These were quantified and subjected to statistical testing. In all but one test, significant increases in skill could be detected from the earlier to the later batch of reductions, despite the drop in toolstone quality. Significant improvements in the consistency of the knapper’s output could also be detected. However, the switch to a more challenging, nodular chert did require extra shaping, which resulted in more waste. This masked visible progress towards producing a less costly core. Overall, our results do not support the assumed primacy of toolstone constraints over other factors in influencing the morphology of flaked stone tools.     

Hits and misses when throwing stones at mass analysis

Mass Analysis (MA), a well-recognized method of flake debris analysis, has generated significant interest in size-grade variables for investigating prehistoric lithic technologies, criticism of such usage, and combination methods developed to address some of those criticisms. A recent critique concluded that there are significant sources of error that preclude the use of MA for investigating prehistoric assemblages. We disagree with this generalization, but recognize that uncritical application of MA by non-lithic specialists is unlikely to yield useful results. Confusion as to what constitutes MA versus other size-grade approaches is a significant consideration. We address these issues as well as replicator variability, raw material, debitage mixing, diagnostic signatures, and the necessity of multivariate analysis in demonstrating that in many cases the attacks on MA are based on faulty evidence or are misguided. We advocate the use of a multiple lines of evidence approach that incorporates aspects of MA. Continued experimentation and application to particular archaeological assemblages in a cyclical fashion is necessary to explore more fully the utility of MA.     

Production Skill and Paleoindian Workgroup Organization in the Medicine Creek Drainage,Southwestern Nebraska

Extremely skillful stoneworking is widely cited as an important characteristic of the Paleoindian period in North America. This paper considers differences in finished and unfinished projectile points and bifaces from two Paleoindian sites in the Medicine Creek drainage of southwestern Nebraska with this in mind, arguing that these differences reflect significant differences in the overall level of skill of the stoneworkers who used these sites. Recognizing variability in Paleoindian flintknapping skill has implications for the organization of landuse in the Medicine Creek region and for our understanding of the archaeology of the Paleoindian period in general.     

Introducing a new experimental design for controlled studies of flake formation: results for exterior platform angle,platform depth,angle of blow,velocity, and force

Potential variables that underlie variation in flake size, and in some instances shape, are investigated in a newly designed experiment. This new design, which utilizes glass cores molded to a specific shape, results in flakes that are identical to archaeological ones. Variation in exterior platform angle, platform depth and angle of blow all directly affect flake size, and in the case of exterior platform angle, flake shape as well (in spite of constant core surface morphology). In treating velocity and force independently, neither is found to affect flake size or shape. These results have implications for understanding different strategies that flintknappers may employ to control the size of their flake products.     

The relative effects of core surface morphology on flake shape and other attributes

It is long been thought that many flake attributes, including both size and shape, are largely due to the morphology of a core’s flaking surface, yet this has never been tested under strictly controlled conditions. Using molded glass cores with surface morphologies that highly resemble prehistoric ones, this experiment demonstrates that while core surface morphology does exhibit some influence on flake size and shape, a high degree of variation in flakes produced with the same core surface morphology shows that the effects of other independent variables, such as exterior platform angle and platform depth, have an even stronger effect. A major implication of these results is that current approaches to reconstruct prehistoric knapping strategies are overlooking significant sources of variation.     

New experimental evidence on the relation between percussion flaking and flake variation

Controlled experiments in percussion flaking allowed for objective analysis of relationships between variables of flake production and those variables which are attributes of the final result. The independent variables, those controlled by the flintknapper in the production of stone tools, include force and angle of blow, platform thickness and exterior platform angle. The dependent variables are those attributes of the flakes which are often used in current lithic analyses and include interior platform angle, length, thickness and flake termination. The results clearly show that exterior platform angle is highly significant for understanding many aspects of flake production. These and other relationships between the independent and dependent variables are also discussed.     

Fracture markings from flake splitting

When a flake is split longitudinally during its detachment, it can leave several kinds of fracture markings, termed here split marks, on the flake scar. Observations from contemporary knapping are considered together with mechanics and fractography for understanding the formation of the split marks. These markings on a negative flake scar can indicate the splitting of a flake during its detachment. Recognition of flake splitting is of archaeological interest especially for technologies where the flakes were utilized.