Archeological Testing at Valles Caldera National Preserve

The Valles Caldera National Preserve in the Jemez Mountains contains one of the most prominent obsidian source locales in the western United States. Prehistoric use of this important tool material over at least 10,000 years has resulted in a landscape of large deposits of manufacturing debris nearby sources of obsidian outcrops. In August, 2007, OCA worked with the cultural resources crew of the VCNP to map and collect artifacts from the surface of LA 26917, a site that encompasses nearly ½ sq km of the preserve. OCA then completed test excavations at the site, consisting of 12 1 x 1-m excavation units and 30 shovel test pits placed to gather data on different landform settings within the site. The test excavations produced nearly 9000 lithic artifacts, the vast majority of which were made from the locally available obsidian. Recovered artifacts indicate repeated use of the site since the Paleoindian period. Analysis of excavation results included detailed soils descriptions, analysis of size and-weight sorted artifact debris, and obsidian hydration rind measures to evaluate effects of mechanical and biological soils disturbances. A major goal of the analysis is to illuminate site formation processes and to evaluate the degree to which cultural deposits have been affected by bioturbation and other post-depositional processes. As one of the first major excavations on the VCNP, the results of this study will help guide future archeological research in the Caldera.


OCA Principal Investigators Pat Hogan and Dick Chapman survey a
two-track road.


Crews excavating shovel test pits at the Valles Caldera National Preserve

Project area at dawn


OCA crew testing the soils for potential buried cultural deposits

Obsidian deposits exposed to the surface


Archeologist Tim Seaman holding a large obsidian cobble

OCA crew chief (and now Laboratory Director) and a University of New Mexico Ph.D. candidate Scott Worman excavating a deep test probe unit


OCA crew participating on the project

Profile of excavated deep test unit


Elk visiting the project area