I am defining wear patterns in this section as the visual appearance and feel of the usage edge when the PES is found in the archaeological record. I can think of at least three (3) items that contribute to wear patterns. These are 1) function, 2) stage of exhaustion, and 3) events that occur after the tool is lost or discarded by its user.
Function probably has the most impact on the wear pattern. Working hard materials such as bone or wood will leave wear patterns that are extremely different from the ones that are created by working soft materials such as hides. When I make this statement there is an inherent assumption that the usage edge being inspected is dull (near exhaustion) and needs to be resharpened. For example, there is little difference in the wear patterns of a PES that has experenced only one (1) "scraping motion" working wood and a PES that has made only one pass working hides. Both are still extremely sharp. It is only after extensive use that the wear patterns of different functions become apparent. Both function and stage of exhaustion contribute to the wear patterns the archaeologist observes.
The third item I listed above, events that occur after the tool is discarded by the user (formation processes), does have an effect on the wear patterns. Obviously, a PES that has been rolling around in a river after being discarded by the user is going to be altered. Lying on a deflated surface and being sand blasted for 10,000 years will also alter the wear pattern. Generally, these post discard wear patterns can be identified by the archaeologist and dealt with accordingly. With this said I will no longer discuss this process.
Before I discuss some examples, I want to remind the reader that the wear patterns on the PES result from the last function the tool was performing. Each time the PES is resharpened, the evidence of that previous function is partially or totally erased. It is easy to fall into the mental trap of believing that a PES with hard use wear has always experienced hard use. Remember, this tool has had a lifecycle that probably began as a hafted flake knife. And, at that stage in its life, if it had been lost, it would not have been classified as a PES.
Examples of Hard Material Wear
In my data, I separate wear patterns into some
step fractures (82%), many step fractures (10%),
smooth (5%) and unused (3%). This PES
belongs to the common category of some step
This typical step fractures wear pattern results from use on hard materials. The jagged distal edge on this PES, visible in the ventral (left) view, is another characteristic of hard material wear. This example is a little extreme, but on close inspection, most PES will have some degree of a jagged edge similar to this. I believe this is the result of working materials that do not have a concavity that mates to the PES. Probably, most of the time the material being worked was not even concave, but convex. An analogy would be scraping a broom handle with a pocket knife. The two (straight knife and convex handle) do not have mating surfaces, and therefore, both leave an impression of their form on the other.
The wear on this PES belongs in the category of many step fractures. Notice how the distal end (bit) has been undercut by the many step fractures. This extreme wear strongly suggest that this PES was hafted. It is very difficult to comprehend that this amount and type of wear could have occurred to this PES if it had been held in the fingers. The jagged edge is also visible on this PES, but it is not as extreme as the previous example.
This PES is classified in the many step fractures category. However, it really belongs in a group by itself. Notice the large step fractures that have been removed from the ventral side. This type of wear is extremely rare and, therefore, suggest that this tool was being used in an unusual manner. I suggest that it was being hammered on the proximal end similar to the way a steel wood chisel would be used. However, the proximal end shows no evidence of impact. Is this evidence for hafting?
Examples of Soft Material Wear
When I began the planning for this section on the PES, this artifact was the first one that came to mind. It is my favorite and partially responsible for the long hours I have spent studying this tool type. It belongs to the small percentage group I call smooth, which I indicated above accounted for only 5% of the PES in my data. As is visible (I hope), the distal edge is extremely smooth. This smoothing continues halfway up the distal end's face on the flake ridges. Under 10X magnification many orderly, parallel striations, oriented almost perpendicular to the ventral face, are visible. There was obviously some grit between this tool and the surface it was working.
I can remember the first time I saw this PES because it was the first time I had seen this type of polish (wear). I remember discussing with my father how much rubbing on a soft hide one would have to do to polish a rock like this one was polished. As time passed, we would occasionally find other PES with this polish and the same discussion would occur. Yet, over the years I was never satisfied with the answer that it was soft hide wear. About six years ago, I had the privilege to view the Lindenmeier material that was excavated during the two years the Denver Museum of Natural History worked at the site. In that collection there was a PES that was polished similarly to this one and it was still covered with red ocher. It had not been cleaned. Now I had an answer with which I was satisfied. At least one of the tasks the very smooth PES were performing was grinding ocher.
This is another PES that belongs to the smooth category. It is smaller than the brown one above, but it is actually more polished. Unfortunately, it does not scan as well as the one above. I have included it because it does show the polished face in the ventral view which makes an angle of 55 degrees with the ventral face. The same angle on the above brown one is 85 degrees. Why are the two angles so different? Is it because of the different tasks the two were performing? Is it because of the different ways the individuals held the PES? Or, if hafted, is it because the built-in angles between the haft and the PES were different? I favor the last explanation.
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