Wednesday, October 20, 2010

Lions and Curses and Nazis, oh my!

parc S stormabrewin
Can you see that storm a brewin'?

Archaeologists deal with some pretty dramatic circumstances. According to a History Channel documentary I happen to own, we are constantly in danger of noxious gases, earthquakes, attacks by local landowners, curses and Nazi’s. I couldn’t make this stuff up if I tried. These may be legitimate worries though, since I too feel like I’ve finally earned my archaeologist’s fedora. For the last few weeks, we at Parc Safari have had to deal with the worst of the worst. We have had (gasp) inclement weather.

All joking aside, the weather has actually been pretty poor in Montreal of late. And apart from making my teeth chatter and my llama-wool socks wet, the rain has been a bit of a problem on site. In fact, only last week group B was forced to come home in the middle of a field day, despite Chris and Colin’s promises that we (like the US Postal Service) would not be deterred by rain nor snow nor sleet.

It is an unfortunate fact that excavation relies heavily on our ability as field workers to actually see the unit. When the weather is poor, the rain poses some problems. What my fellow students and I recently realized is that rain makes the soil deposits wet (an incredible revelation, I know). This made using a flow diagram, such as the one we were given (to determine the composition of deposits) more difficult. It was harder to differentiate between layers by colour for instance. What I mistook for a change in stratigraphy turned out to be what Colin called a “tub ring”. The rising water table and rainwater left a ring of discolouration on the walls of the unit after we finished bailing.

On the other hand, the rain would have been fortuitous if we had we been using a Munsell chart to determine colour. This is because the rain would have "moistening it until it no longer darkened" which is the proper technique for Munsell. Unfortunately our Munsell chart chips are not waterproof making them useless in the rain. In better conditions a field worker is expected to record not only the colour and soil type (which we tried to do) but also the inclusion size and surface details of each stratigraphic layer (Roskams 2010). We did not make note of the inclusion size but we did, as I will discuss later, map in ‘surface details’.

On a side note: an interesting fact I learned through the readings is the difference between soil and deposit. Soil is created in situ, if you will, by organic means whereas a deposit is brought into it's current location via natural forces like flooding and erosion or by human means (Roskams 2010), such is the case for Parc Safaric where backhoes and large machinery were likely used. But I digress...

Wet weather, along with a high water table also made it difficult to excavate. Not only were the sides of the unit highly unstable but seeing the bottom of the unit was near impossible for group B. According to Colin they could not bail fast enough to keep a dry bottom. I think underwater salvage archaeology is incredibly interesting, but that’s not what we are supposed to be doing here at Parc Safari!

Thankfully, all was not lost. We were not going to throw in the metaphorical trowel. We were better than that as archaeologists, gosh darn it! Given that group B could not actually excavate, they retreated honorably into drier conditions for a lab-style lesson. We in group A managed to practice a few skills that didn’t involve digging too much deeper. Since we uncovered a few more bones (including what is part of an axis) and rocks it was decided that drawing the unit was the next step. Interestingly, we also uncovered a large embedded piece of heavy-duty metal cord.

Chris and Colin led us in a quick lesson on how to draw and map a unit. I have had plenty of practice on mapping, from my field school this summer but only in the base-line drawing method. Chris and Colin proposed three alternative ways to map a site or unit.

  1. Hip chains

This method involves using a forestry tool called a hip chain. It is a biodegradable rope material that is released from a canister hung off of a person’s hip. Like a pedometer, hip chains measure distance, though in metric terms instead of steps to help an archaeologist map a large unit or entire site.

  1. Triangulation

This method is used to determine the location of a point by measuring angles to it, from known points at either end of a fixed baseline, rather than measuring distances to the point directly. To use this method you anchor your two tapes at known points (in our case the corners of a unit). Then you level them with line levels and you measure the distance of each to the object. You record this. Then you scale the measured distances with a compass and draw circle segments; the point where your segments intersect is where your new previously unknown point is. Plot this on lattice graph paper.

  1. Drawing screen

This method is very useful for smaller units or those that have a large quantity of material to draw. It involves putting a physical screen over the unit, which corresponds to a metric grid system and plotting the results on lattice graph paper.

The method we used on Friday was the base-line method of drawing. A ‘base line’ is set up along one axis of the unit, using a tape measure along the string. A second tape measure is used to ‘eye-ball’ a point (on a bone, interesting feature etc) that you want to draw, and the distance from the baseline is used. Often a plumb-bob is used for deeper units to help with the estimating. The coordinates are then called out to someone who has a scaled map set up on lattice graph paper and the points are plotted.

He's down there somewhere...

Weather is something we as archaeologists have no control over. We can pray to the (undead) spirit of Lewis Binford all we want but sometimes the day just turns out soggy. We are a resilient type of academic, willing to brave the elements, but we are also bright enough to know when to pack it in. No, we have not found lion yet. I want to believe he’s there though, waiting in our watery unit, biding his time.

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