GEOLOGIC MAPS FORM THE FOUNDATION FOR PALEONTOLOGICAL RESOURCE EVALUATIONS IN UTAH’S NATIONAL PARKS

Spectacular rocks exposed in Utah’s national parks include many fossiliferous intervals. In cooperation with the Utah Geological Survey, National Park Service interns have been conducting comprehensive inventories of paleontological resources located within Utah’s national parks. The goal of this work is to identify new fossil localities and to assess the distribution of fossils within formations to establish baseline paleontological resource data to support the management and protection of non-renewable fossils. Because of the vast size of the parks, accurate detailed geologic maps are essential for focusing field assessments on the formations and deposits that have the highest potential for containing important paleontological resources. Modern geologic maps provide several advantages over older maps, including providing greater detail, more accurate placement of geologic contacts, better division into members and even submembers, and much more detailed mapping of surficial deposits that cover fossil-bearing strata.

Recently the Utah Geological Survey completed new 1:24,000-scale geologic maps of Zion National Park and surrounding area. Important vertebrate fossil-bearing formations include the Triassic Chinle Formation and the Jurassic Moenave and Kayenta Formations. These maps formed the foundation of a detailed field inventory, saving significant time and expense, and focusing efforts on key areas. As a result, we identified over 100 new sites. Several terrestrial vertebrate body fossils were found, including the remains of phytosaurs, aetosaurs, metoposaurs, and a possible ornithischian dinosaur. Dozens of new dinosaur tracksites were discovered in the Whitmore Point Member of the Moenave Formation and the Kayenta Formation, including numerous Eubrontes and Grallator trackways, as well as probable swim tracks. To put our results in an easily usable format, we are using Geographic Information System (GIS) programs to not only record site localities, but also to create paleontological sensitivity maps that key the type and distribution of fossils to each geologic formation or deposit. These maps will aid the park service and state and local officials in making decisions regarding the protection of fossil resources both in and near the parks.