Battling the Water Table

Perhaps we can go into building underground houses after this project

Perhaps we can go into building underground houses after this project

I mentioned previously the surprise occupation located 185cm below the surface, it turned out to be a rather good occupation level with ample bones and artifacts. Our problems arose as we got a bit deeper into it and encountered the water table – unlucky for us there happens to be a high water table in the area. So, now we not only had to worry about creating shoring that would prevent us from being covered in sand at any given moment but also how to draw the water away from our active units.

It's just a bit of water, no big deal.

It’s just a bit of water, no big deal.

In the end, our solution was sump pumps. We had four pumps running around the clock to keep the water low enough that we could excavate through the occupation level; we started this area at the end of winter and as spring thaw hit us we had to try and dig the pumps even deeper to keep on top of the water situation (we had to quickly, but still properly, excavate sump pump holes in areas of low artifact returns). We also discovered that water-logged sand is also rather prone to giving out suddenly – quite aggravating when you’re trying to keep the walls looking good for photographs, profile drawing and site visitors (no one wants to be accused of having sloppy walls, no one).

13-246~2491We only recovered 5 projectile points from this occupation level – not great but not terrible. They’re a bit mysterious though, they don’t really fit with the type of points we were expecting to find at that depth. We were expecting thicker, chunkier points, but these ones are relatively thin and well-made. They look like they should be Late Period points but that doesn’t fit with the order of the occupations we have represented on our site. So, at the moment our best guess is that they are intermediate points from the transition of Early to Middle Prehistoric – which is exciting because that means they’re quite old indeed (7 – 9,000 years old).13-246~2971

Normally, we do radiocardon dating of the bone to back-up our estimation of the date based on the projectile points. Our sneaky low occupation had plenty of bone but the water table got one up on us this time. The bone looked fantastic as you exposed it from the damp, organic-rich sediment but as soon as you tried to remove it from the ground it would crumble into a pile of tiny fragments. Through much painstakingly slow work we managed to get some of the bone out in relatively one piece and sent it off to the labs in Florida.

It looked so good until we tried to take it out.

It looked so good until we tried to take it out.

Sadly, all our efforts were in vain. The constant movement of water in the area had leached all of the collagen out of the bones, leaving nothing for the lab to extract and test for us. We sent them almost 10 samples and each one came back with the same disappointing outcome. Not to be discouraged, we were set upon the idea of doing OSL (optically stimulated luminescence) dating. This method of dating involves taking samples of sand from deep within our profiles and using science-magic (ok it’s real science I just don’t know all the specifics of how it works) they analyze the last time the sand was exposed to sunlight.

Lining up the OSL samples.

Lining up the OSL samples.

Taking the samples took an afternoon, waiting for the lab in Scotland to get us some dates took about 5 months longer. Our preliminary look at the dates supports our Early to Middle transition deduction with the date range being 6780 – 8700 years BP. We still need to do some further analysis and make sure everything matches up like it should between all the records, but we’re excited and this is definitely the oldest Alberta site I’ve worked on thus far.

All the Pretty Things

As promised, here are some of the pretty, shiny things that we found. We also found a ton of flakes – the garbage that would have been left over after making fine tools like these (but they’re less pretty to look at), as well as a fair amount of burnt or calcine bone (animal). Animal bone was often burned at high temperatures in order to make the bones brittle. This, in turn, made it easier to get out the marrow which was a valuable source of nutrients. We were really hoping to come across the hearth or boiling pit where they were doing this but alas, we did not stumble upon it this time. But by looking at the concentrations of finds, you start to get a feel for how the area was divided up  – projectile points were being made or retouched (resharpened) near the end of the promontory, while the cooking would have taken place further back from the edge where the landform widens out a bit.  It’s still a fragmented picture of what was going on at the site, but it is a start.

(you can click on the pics to find out a bit of info on them)

Hunting for Sites

Part of our challenge for this trip was to relocate the sites we are now excavating. IMG_4032The six sites were first identified two years ago, and we had a rough idea where most of them should be.As added insurance we also brought along the archaeologist who first identified the sites and she seemed to mostly remember where we wanted to go, mostly.

Stone adze-cut stump - the stone crushes as it cuts, this can be seen if you look closely

Stone adze-cut stump – the stone crushes as it cuts, this can be seen if you look closely

The first one we rediscovered is a tiny little lookout – a steep climb and a rocky seat, but a great view of the area. It had some interesting traditional use markers at the bottom of the hill: a tree tied in a knot (which has subsequently fallen over, but still cool), and a stump that was cut with a stone adze (you don’t see that much within the last century…).

Afterwards we wandered done to the river where there is an old cabin, as well as some of the machinery used to winch in barges – the only way to access the area without a plane. There isn’t too much left other than the corner of the cabin and some of the foundations. We don’t plan on doing any further work at this spot, but still fun to poke around.

IMG_4054 IMG_4059

We discovered that one of our sites has been blasted through (they said is was an accident…) while they were busy gathering rock to build the road down to the modern ferry landing spot. We did a bit of shovel testing to see how much of the site they might have left us safely tucked away in the trees, but it looks like they did a pretty thorough job of destroying the high potential areas.

One of the sites required some serious climbing skills – the hillside seems almost vertical in places, luckily I was sent off to another site while the other team investigated this spot. Apparently, if you survive the climb the view of the surrounding valleys and rivers is fantastic. They continued on to the next high site where they found some very cool points (pics of awesome finds to come next post), I suspect more work will need to be done there or they will have to avoid the area with their mining operations. However, I am skeptical of the second option given what already happened when they were building the road.

IMG_4062

Crossing the little creek to get to the last site

The last site is tucked away in the forest on a good rise, across the river. That’s where I spent several days and will likely spend a few more. There are the remains of a tent foundation – evidence of traditional use of the area. But shovel testing reveals that the occupation of the area goes much further back than that – lots of flakes, microblades and general evidence of stone tool making in the area. The area didn’t start off that promising but that was just because we weren’t looking in the right places.

Pictures of some of the pretty rocks we’ve found to come soon!