Wednesday, November 3, 2010

Packing it in. Or, how to excavate TR2 in one afternoon.

Last Friday was our last day in the field. The occasion brought the two groups together, produced several finds, and created a general excitement as we collectively tried to get as much done as we could before we packed it in for the term. As we worked quickly under a slightly overcast sky and brisk weather, we were very aware of the time constraint—as Chris and Colin put it, everything that we did that day needed to be finished. That day.

This week the group split up to maximize our time at the site and the first task at hand was to continue exposing the extended portion of our first trench (PS2010 TR1) since Group A had further exposed portions of several bones. Several bones were unearthed, including a rather large, short, and squat femur which soon became one of the biggest finds of the day.

At the same time, we continued test the subsurface deposits between our first trench (PS2010 TR1) and the Watusi unit, using the same method described in last week’s blog post—a simple and inexpensive coring device. As previously mentioned, we do not yet have a clear idea of the stratigraphy of all areas of the site since many of the layers have been disturbed by the construction of the road. The Parc Safari site was thus a good place to get an idea of the three-dimensional matrix of an archaeological site: most of the site consists of sediment and soil deposits (most of them anthropogenic, or altered by human activity) or constructions (the road), with scant artifacts. While it is largely an additive deposit, consisting of the various layers of animal burials and deposited refuse, there is a considerable amount of deposit subtraction that has occurred through the construction of the road (Kvamme 2005, 425). This post-depositional disturbance accounts for the mixed surface finds that we encountered in our trenches, close to the road.

The crew took turns coring, finding a similar stratigraphy to what had been encountered in the Watusi Pit. Making our way slightly northeast to TR1, we took several samples and found the same thing each time: past the top layer of vegetation there was (1) a loose organic layer, with some roots and grass, (2) a more densely packed layer of soil, and (3) a final layer somewhere between the dirt and clay.

One last core was left, close to TR1, and it was my turn to have a go. It was a bit tougher than I thought it would be, but after briefly contemplating jumping on the handles and treating it like a pogo stick, I gave it one last good shove and in the ground it went. This one was slightly different. After the topsoil there was simply the loosely packed organic layer and the more densely packed layer of soil—so now we have an idea of where the stratigraphy changes in that portion of the site.

To get a better idea of the subsurface deposits, next year’s team may be able to use the brand-spanking new Ground Penetrating Radar (see previous post); however, this year it was not at our disposal. We did have one last project at hand, though—as we were simultaneously continuing to excavate/map TR1 and coring, we began and completed our second trench, PS2010 TR2.

The location of this second 50cm x 2m trench was determined by a hypothesis that Chris and Colin had about the mapping of methane emissions by the geography department. If the methane emissions could be proven to be higher near units that contained bone, then there might be a correlation between the methane level in the soil and animal remains, thus allowing us to include chemical mapping in our arsenal of terrestrial remote sensing techniques.

Chris and Colin seemed to be on to something, and we eagerly excavated the unit next to Peeper 3. Being careful to follow the Golden Rules, we unearthed an array of individual bones, including a tailbone in the southwest portion of the trench. After carefully mapping in our finds, our instructors nearly had to pull us away from our trowels to pack up. It appears as if you really do find everything on the last day…

That lion will have to wait for next year.

Kvamme, K. 2005. Terrestrial Remote Sensing in Archaeology. In: Maschner, H.D.G., Chippindale, C. (Eds.), Handbook of Archaeological Methods. Lanham, MD: AltaMira Press, pp. 423-77.

Roskams, S. 2001. Excavation. Cambridge: Cambridge University Press.

Stein, J.K., 1986. Coring Archaeological Sites. American Antiquity 51, 505-527.

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