– post by Dr. Peres and Mason P.
Today was the first day of Week 3. We arrived on site to find that our three deepest units contained water from this past weekend’s rains. The students had their first chance to bail the units.
By the end of the day we had nine Excavation Units (EU) being actively excavated, with another ready to be started tomorrow. All of our units, with the exception of one, are rectangles that measure 1 meter x 2 meters.
To begin working in an EU, first we had to remove all brush and loose vegetation from the marked off unit. After clearing these out, we then used a laser level to accurately measure the depth of each corner of our 1×2 meter units, as well as the center (all measured below a set datum point). To do this we used stadia rods with adjustable sensors and a laser level set up over the datum point. We took depth readings to within the half centimeter. These were noted so that we could compare the depth of the EU as we go down each level.
After accurately measuring at what depth each corner was, we began to dig. Our first task was clearing out the numerous surface roots within the humic layer, or the decomposed plant remains and roots located at the top of the soil profile (You can read more about soil profiles and how soils are typed or classified). Once this had been cleared out and properly screened for artifacts, we began to dig into the soil below. We dig in a controlled systematic manner, sometimes called schnitting or shovel skimming, taking off a centimeter or two at a time. This allows us to map any artifacts or identify features as they appear.
More pictures and details to come tomorrow…