18 Sep Archaeologist For a Day
I hope everyone has been safe and is doing well. The days have been going by so fast and I can’t believe my internship is almost over. I have been loving working here at Wupatki and getting to see what everyone does. One of the interesting things about working here is understanding how the Flagstaff National Monuments have preserved ruins over time. I had the opportunity to work with the archeological team a couple of times to see the work they do and everything that goes into preservation.
My first day I worked at East Mesa where the preservation worked mainly involved stabilizing the walls and removing invasive plants. The other two days I worked at the Wukoki pueblo, where we focused on stabilizing walls with mortar and monitoring the condition of the pueblo structure.
Fig. 1: A wall of one of the ruins in East Mesa. There is hardly any mortar, but we stabilized it as best as we could.
When I was at Wukoki, I learned more about what goes into the mortar and how preserving the pueblos at Wupatki has changed over the years. The National Park Service initially reinforced the pueblo partially in the 1940s by installing wood braces and wedges. Cement and mud mortar were also used to stabilize the walls. By the mid 1950s, more stabilization was required, so workers used Portland Cement covered with clay mortar was used the stabilize the walls. They also braced the walls internally by reinforcing it with flat steel bars. This definitely worked for a long time. The mortar was very strong and holds up well, but it’s actually TOO strong. Because the mortar is strong, it resists erosion. This can be problematic because air and water will start to erode the sandstone blocks instead of the mortar. This means that over time, the sandstone that is the building itself will start to deteriorate well before than what should be expected.
Fig. 2: A wall in Wukoki that I worked on. In between the sandstone blocks is fresh mortar that I put down to stabilize the walls.
Current preservation involves creating mortar that uses sand, locally sourced red clay, and a gluing agent. This is as close to what mortar the Native Americans used 900 years ago when they were occupying the area. The mortar is more natural now and will be more preferential to eroding than the sandstone. Preservation is always a continuous process. Since Wupatki receives many visitors every day, the archeology team has to put down new mortar about every 4 years. This was a really exciting experience I got to take part in, and I gained a new insight on how much work it takes to preserve the ruins of Wupatki.