By the Trowel

The last couple of weeks have been busier than normal. We wrapped up a field survey near Abiquiu which took a total of five days to complete, three days longer than what was initially expected for an area just over 100 acres in size. However, this area is relatively close to the source for Pedernal chert and Jemez obsidian, and there were previously recorded sites in the area, so it makes sense that there would be sites within our project area. This project actually felt more like a marathon recording session than a survey, simply because we could survey more than 20-30 meters at a time without someone encountering additional artifacts

Why digging slowly is important. Notice the chert axe embedded I the floor of the test unit.

This week I’ve gotten a chance to actually participate in excavation, which is nice as it has been almost three years since the last excavation project I worked on. This project was located in a residential area in the city of Santa Fe, on an undeveloped tract of land. The site itself was recorded for the first time four years ago, but the site is only being excavated now because the tract is slated for development. Data recovery/excavation projects are more expensive than survey, so even when sites are recorded during pedestrian survey, they usually aren’t excavated unless it is absolutely necessary to do so, as in this case where development of the land will negatively impact the site.

Same chert axe from the excavation.

The five test units within the site were determined by the locations of artifact concentrations defined in the initial recording. Each test unit consists of a 1m x 1m square, and the goal was to dig 10 cm levels. The first level can be challenging, as the surface is hardly ever nice and level to begin with. For instance, if you define the surface of the southwest corner as your baseline, the northwest corner may be 2 cm above level, the northeast may be 4 cm below level, and the southeast may be 2 cm below level. What this means is the you will have to remove 10cm of dirt from the SW, 12 cm from the NW, 6 cm from the NE, and 8 cm from the SE in order to get all the corners down to 10 cm from level. Of course, you have to excavate all the material within the test unit, not just the corners, but the goal is to have a nice, level surface at the bottom of your level. Typically, in New Mexico, one needs to excavate by trowel from the beginning. In other places it may be possible to simply shovel out of the way a layer of overburden to reach a cultural layer that will then have to be continued by trowel. The reason we excavated in 10 cm levels was to observe the frequency of artifacts in each level, and excavation of a level was considered complete by having excavated two successively sterile (devoid of artifacts) levels.

Thankfully, the project area was located on a terrace above the Santa Fe river, and the soil was soft and made for easy digging. Every bit of soil removed from the unit needs to be screened, so its not just about hucking out chunks of earth willy-nilly. There may be artifacts hidden in clods of soil, so all the material removed is (literally) screened for artifacts. By this I mean that the soil is poured into a wooden box with the base consisting of quarter-inch steel screen. By shaking the box, you can break up the soil and allow anything smaller than a quarter-inch to fall through into your back-dirt pile. Once all the dirt has fallen through, you can then look through the left-over material for artifacts. If there are any, they are collected and placed into a bag designated to hold any artifacts from that particular level. Most of our test units were excavated to a depth of 50 cm (meaning that the 30-40 and 40-50 cm levels were devoid of artifacts), so at this particular site, artifacts were relatively shallow with respect to the ground surface. At an excavation I got to work on in France, the floor level was at least five feet below the ground surface, and at other sites it could be even deeper than that. It really depends on how rapidly depositional processes at that location can bury the site.

Well, the SAA conference is here next week, so I suppose it’s time to finish up my presentation. While I am excited to participate in my first SAA conference, I have to admit that I’m also looking forward to being over with it. While I have presented research at other conferences and in public settings before, there is something extra intimidating about presenting at the SAA. Until next time.

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