GEOLOGICAL STUDIES IN SUPPORT OF ARCHAEOLOGY AT NELLIS AIR FORCE BASE, FROM CLASSICAL STUDIES TO INNOVATIVE RESEARCH

The US Air Force maintains responsibility to inventory, evaluate, and protect cultural resources and archaeological sites as they pursue their primary training and testing missions on the Nevada Test and Training Range (NTTR). Early geological studies (circa 1993) focused on discriminating between the different types of surficial deposits that hosted cultural features to determine if any statistical correlation existed between surface deposits and cultural features. Subsequent studies (2003) mapped the distribution of bedrock sources for lithic cultural technology on and around the NTTR. As archaeological studies evolved beyond compliance surveys, they began to incorporate supporting geological studies.

From 2005 to 2009 several playa studies were completed using fossils, stable isotopes, C-14 dating, and surface mapping to determine the paleogeography, paleohydrology, and paleoclimate history of the late Pleistocene paleowetlands and pluvial lakes formerly occupying these modern playas. These results were used to direct archaeological surveys toward areas once favorable for aboriginal use. Mapping and differential GPS surveys were used to estimate erosion rates and their effect on older cultural features. Additional geomorphological studies were conducted to help discriminate between natural causes and anthropogenic causes of unusual features of unknown provenance.

Encouraged by the results of these independent geological studies, the Air Force began to incorporate geological studies into focused multi-disciplinary studies involving geomorphology, archaeology, and ethnography. Recent studies (2011 - present) use surface mapping, petrography, paleontology, C-14, cosmogenic Be-10, and varnish microlamination (VML) age dating to reconstruct a detailed paleoclimate history of complex paleowetlands. An age/stability model has been developed for alluvial fans using soil profiles, surface features, co-existing botanical communities, and color analysis of satellite photos to help predict which fan surfaces are most likely to preserve ancient cultural features.