TELLING TIME AT GRAND CANYON NATIONAL PARK: A COMPILATION OF NUMERIC AGES FOR ROCKS EXPOSED IN GRAND CANYON
Interpreters should use numeric ages when communicating geology to the public as they serve as important translations of geologic ages. We reviewed the technical literature and consulted with researchers to compile the best ages of Grand Canyon rocks (http://www2.nature.nps.gov/geology/parks/grca/age/). By best we mean the most accurate and precise ages, given the parameters of dating techniques and available information from the rock record. The age chart was published in a variety of general articles that also explained how geologists tell time and why these dates are important. The primary audiences for this work were interpreters (rangers, guides, authors, and publishers) and resource managers. The goal was to develop a single list of numeric ages that users could apply consistently, thereby facilitating comprehension of the geologic history of Grand Canyon. As a result of our project, the ages given for Grand Canyon rocks are already more consistent in interpretive media, park documents, and popular publications.
This project is a good example of collaboration among scientists, resource managers, and interpreters. Interpreters have a significant need for consistent, reliable ages for Grand Canyon rocks, and for a better understanding of geologic dating techniques. This compilation and accompanying information about dating methods can help interpreters address the sociopolitical controversy regarding deep time and evolution. Resource managers benefited by having an internally consistent and scientifically credible time scale to use. Finally, working directly with researchers has fostered communication and credibility among park interpreters, resource managers, and the academic community.