Today was Day 4 of the 2017 Crow Canyon Field School and we spent the day in the laboratory. For some archaeologists, the lab is where the magic happens so to speak.
We first started off by washing artifacts. Dirt tends to stick to artifacts, especially the ceramics. So lab archaeologists will use cutting edge technology to clean the dirt off lithics and ceramics. This technology: toothbrushes, plastic tubs, and a screen. Each bag of artifacts from the field has to be kept together when washing, we don’t want to break context and provenience! While cleaning, we were instructed not to scrub really hard. Sometimes paint will come off certain ceramics if you brush vigorously. After gently scrubbing the finds with a toothbrush, all the artifacts from a single bag were laid out to dry on a screen, label included!
Next, we were taught how Crow Canyon sorts out its clean artifacts into categories such as bulk sherds, bulk chipped stone, non human bone, etc. We sorted, weighed, and entered the data into the database as a team. After that we learned about dendrochronology. Dendrochronology is fascinating. It is the study of time through tree rings. (Dendro = “tree”, chrono = “time”, ology = “study of”). If archaeologists find a structure on the site and it has beams still intact, they will take these beams to the lab. The specialist will look at the tree rings and then compare those to a known timeline of tree rings going back two thousand years! Then we can get an estimate to when the building could have been built.
After lunch, (what a packed day!) we made our own clay from a clay source on Crow Canyon property. This takes time, temper (crushed up pottery), water, and lots of shaping. All eleven of us will have clay waiting for us next week to make our own little pots. We ended the day by learning about flotation, which is taking a sample from the field and running it through mesh screens with water to separate light fraction and heavy fraction. Light fraction is where the seeds, beads, and other small artifacts will be. The heavy fraction is the gunky mud and where the larger artifacts will be. This process also uses high tech equipment: buckets, a plastic spoon, mesh screens, and lots of water. In your sample bucket full of dirt, you add water, stir, and then pour carefully over a screen to catch the light fraction. This is because the light fraction will float to the top of the water as you stir the gunky stuff at the bottom. Once all you have left is mud at the bottom of the bucket and light fraction on the screen, you can hang the light fraction up to dry by making a little baggie out of the mesh. The heavy fraction will be run through a separate screen using a hose. Then those will be dried as well.
Tomorrow we head out to the field again and won’t be back in the lab until next Thursday. I’m sure it will be just as packed and just as productive!
Mary Horabik, 2017 Field School Student