Adam Dunstan and Dr. Richard Terry, Plant and Wildlife Sciences
Soil carbon isotope analysis is a means by which, through chemical analysis of soils once used by ancient civilizations, we can ascertain where they may have been farming certain crops that leave a unique chemical “signature” in the ground. Under the guidance of Dr. Richard Terry, I used this method to analyze soils from the Range Creek Canyon archaeological site, to determine if this method can be useful in discovering the agricultural history of Fremont Indian archaeological sites.
This method works because of the unique chemistry of plants grown by ancient cultures. Maize (Zea mays) uses a different mechanism of photosynthesis (a C4 pathway) than many other plants (which use a C3 pathway), so when it has been grown in an area for a significant period of time, it causes the carbon chemistry of the underlying soils to show a shift in carbon isotopes. Because of this, we can sample soils an archaeological site and determine with reasonable accuracy where farming occurred, in an efficient and fast manner.
This procedure has been used in various Mesoamerican archaeology projects. However, it had not been applied, to our knowledge, to Southwestern United States archaeological sites prior to our research. We decided to test its usefulness, with aid of ORCA grant funding, at Range Creek Canyon, a promising new archaeological site once inhabited by Fremont Indians. Since these Fremont used Maize agriculture, we believed that our method could shed light on where they farmed. However, we were unsure if the method would work due to differences between this site and the Mesoamerican ones Dr. Terry has worked in.
During September through December, 2008, I extracted and analyzed soil organic matter from 4 soil profiles collected from the Range Creek site, in a specific area that we believe the Fremont may have been farming. I prepared the soils over many long hours, applied chemical extraction procedures to them, and then had their carbon isotope signatures analyzed.
The graph below presents our finding. I am pleased to inform our funders at ORCA that we were able to find that this method does indeed work for the Fremont culture in Range Creek Canyon. In one of the four soil profiles analyzed (Mojo 03), we successfully detected a shift in carbon signature in the soil that can most likely only be attributed to Fremont farming in that area. We now know that this method can be applied at that site, so further studies can be done, in cooperation with the University of Utah archaeological team working there, to outline and determine where Fremont were farming at that site. The graph below shows our data more in depth.
This was a very rewarding process for me because, although I had worked with this procedure before, I had never been able to see it through most of the process on my own. With the help of Dr. Terry I was able to. This allowed me to see our method in a fuller context, and gain confidence in my skills as a lab researcher.
One problem we encountered during research was a lack of necessary data about where profiles were collected. However, using data from the internet, and revisiting the site, we may be able to overcome this. Either way, our research established that we can use this method at this site.
Our research has not yet been published. We have worked on a paper to submit to the archaeological team at that site, and have been discussing our results with them. They are pleased with our results and it has opened the way for continued research collaboration. We are also still going to seek academic publishing, preferably in Southwestern Archaeology. Due to timing constraints, I have not yet been able to attend an academic conference to present. Before publishing or presenting, we will need to finish the procedures – although the main part is done and our data is promising, we need to perform tests on a few other aspects of the soil. I continue to be employed through Dr. Terry and I and his team will continue to test these soil profiles in preparation for publishing in the near future.
It is unfortunate that this project has taken slightly longer than expected, but both Dr. Terry and I are very pleased that this method has been successful, and we are therefore continuing to use the method, in cooperation with archaeologists at Range Creek canyon, to outline the agricultural practices of this fascinating culture.
I would like to personally thank ORCA for helping me to take part in a cutting edge research project which has enhanced my skills as a researcher, given me valuable and enjoyable experience, and greatly strengthened my relationship with my faculty mentor.