Microwear analysis-determining the function of chipped stone tools

One of my technical specialties is high-powered microwear analysis, a method by which the function of chipped stone tools can be determined. Pioneered by Semenov (1964) and refined by Keeley (1980), the high-powered magnification approach has repeatedly demonstrated that variability in polish formation on utilized surfaces is related to tool use on different materials (e.g. soft tissue, hide, bone, wood, etc.). Striations, or the grooves and scratches of varying orientation and dimensions which often result from abrasive forces imparted during tool use are important indicators of intentional and unintentional motion, such as friction between a stone tool and its haft and/or the contact material being worked.  Taken together, micropolish and striations provide information on contact material, tool motion, and hafting.  In this manner, the identification of distinct surface and edge alteration of tools can be related to prehistoric patterns of activity and raw material use and utilized in the reconstruction of the organization of cultural behaviors.

Today I continue to work on material from three sites. Two sites were recently excavated by a Cultural Resource Management firm as contract excavations. These sites, which date from the Late Archaic and Woodland periods, were investigated to fufill compliance laws prior to disturbance. As part of the data recovery plans, the principle investigators have included a budget for analysis, a part of which is microwear analysis to determine the function of chipped stone tools recovered on site. A range of formal and informal tools were recovered, and so far, results indicate a wide variety of tasks  including butchery, hide,  and bone and wood working occurred on site.

The third site I am working on is the famous Lindenmeier Folsom site in Colorado. These materials were excavated and/or collected in 1934-40 during work at the site by Frank Roberts. Microwear analysis of a sample of endscrapers recovered from the site reveal that many of them were employed in the later stages of hide working. Edge wear in the form of eroded resharpening scars and heavily rounded edges along with a well formed dull-pitted polish characteristic of dry hide was present (see photomicrograph).  During late stage hide working, the edges of the tools are allowed to dull, so that accidental tearing of the hide during stretching and softening is lessened. Some endscrapers were discarded with sharp, fresh edges indicating use during earlier stages of hide working where cleaning and thinning is the object. These discard patterns illuminate the activities that took place on site, and when coupled with an assemblage of worn out, broken and discarded projectile points suggest active hunting and transport of fresh hides for processing at the site was common.  Here is a prime example of the value of why collections should be curated, as when they continue to be available for analysis, we can continue to learn from them.

Heavily worn and rounded distal edge of unifacial endscraper used on dry hide.

An African-American Homesteading Site – And the Community Who Cares

Over the past week a team of archaeologists from Avalon Archaeology, Denver University and Brown University have been surveying several African American homesteading sites in Southeastern Colorado.  Settlers moved to this area, known as “the Dry” from neighboring states, hoping for opportunity to lay claim to their own piece of land.  People began pouring in to the area around 1916, but many left by late 1930’s – once the local irrigation system faltered and the Dust Bowl ravaged many homesteads.  Some families did stay at the Dry, and several descendants still live in the area today.  Through archaeology, archival research, and descendant oral history interviews, we hope to learn as much as possible about the African American homesteaders who made the Dry their home.

In order to publicize our project and get the word out about the Day of Archaeology, yesterday we held a program for local kids about the work of archaeologists.  Children from Rocky Ford, La Junta, and Manzanola, Colorado came out to participate in a series of activities that taught them to think like archaeologists.  They learned how to recognize patterns in a survey, how to interpret garbage, and how to excavate with careful notes.

Today our work began at 6:30 am.  Because of the high temperatures and lack of shade on our site, we have been working  from dawn until around noon every day.  The task for this morning was to finish surveying a homestead owned by Harvey and Roland Craig, a couple of met at the Dry and lived on there from the 1920’s until the 1970’s.  With such a long period of occupation, there was a large array of features and artifacts.  Our four-person team spent the better part of the morning measuring features, counting surface artifacts, photographing objects, taking GPS coordinates (…and looking out for rattlesnakes).

This evening we held a community talk to discuss our project, field questions, and hear input.  Three descendants of some of the first settlers spoke about their memories of “the Dry,” and why they felt it was important for the stories of these settlers to be remembered for local, state, and national history.  Even after the speakers finished, the crowd stayed around for another hour or so to talk with us and with the descendants.  Some people even brought photographs or articles with them that related to the site, to help with the project!    A day in the life of an archaeologist can vary greatly.  We certainly don’t all keep 9:00 – 5:00 hours, and we don’t just spend our days digging.  Sometimes we get information from things besides artifacts and features – sometimes our sources are people themselves!