South Park Archaeology Project

Special Studies

As archaeologists we of the South Park Archaeology Project are interested in more than artifacts from a site. We are interested in determining, to the best of our ability, how the prehistoric occupants of the area lived. To help generate information beyond the archaeological record we call on a number of specialists to use their scientific methods to answer questions. The results of their work will be available here: Petrified Wood Sourcing Project.

Obsidian Sources
Throughout the western United States obsidian is often the rock material selected by prehistoric peoples for the manufacture of their tools and weapons.

What is obsidian?
Obsidian results from volcanic lava coming in contact with water. In many instances the lava pours into a lake or ocean and is cooled quickly. This process produces a glassy texture in the resulting rock. Iron and magnesium give the obsidian a dark green to black color.

What's the importance of obsidian to archaeologists?
A single source of obsidian is relatively homogeneous in its trace element composition. At the same time the source shows enough variability to allow it to be distinguished from other sources. The identification is accomplished by using a variety of attributes to characterize the obsidian. The use of trace element occurrence is used 'fingerprint' obsidian sources. X-ray fluorescence analytical methods, with their ability to nondestructively and accurately measure trace element concentrations in obsidian, have been widely adopted for this purpose. Since these methods can be applied to artifacts as well as the sources of obsidian it is possible to determine from which source a particular artifact was made.

Results from South Park Archaeology Project
As a result of our surveys we have located thirteen artifacts made of obsidian. The thirteen pieces come from two non-local sources, Polvadera Peak and Cerro del Medio, both sources being located in northern New Mexico. They come from the Jemez Mountains near Los Alamos, over 250 miles south of South Park. The thirteen artifacts come from five different sites in South Park. Four of these sites are located in the northeast portion of South Park, below Kenosha Pass, while the fifth is situated in the center of the South Park near Hartsel. One element that all five sites have in common: where there are multiple artifacts they all come from the same source. We can not say how the obsidian got here: whether the people who traveled through South Park also visited these areas in New Mexico; or whether there was a trade network between the two areas, we do know that New Mexico obsidian is here.

Future Efforts
We continue to hear of local sources for obsidian. It is reputed that there is a source area in South Park itself, another in Fremont County to the south, and a third source in Chaffee County to the west. Staff from SPArP will be searching for these sources and will provide samples to the appropriate parties so the information can be shared.