NPS Paleontology Research Abstract Volume


Emmett Evanoff
University of Colorado
Boulder, Colorado 80309-0315

In 1985, BLM land managers in the Royal Gorge Resource Area requested a paleontologic evaluation of the Garden Park Dinosaur area north of Canon City, Colorado. Some of the oldest dinosaur quarries in the U.S. occur in the Morrison Formation in this area, which include the type localities of such well-known genera as Stegosaurus, Allosaurus, Diplodocus, and Camarasaurus. The area has been used for recreation and grazing, and has limited potential for mining. One of the most pressing concerns was an understanding of the distribution of the fossil bearing outcrops and the location of historic quarries in the area. Because of this need, a paleontologic resources map was compiled which has proven to be a valuable tool for land management decisions.
The first task was to make a detailed surficial geologic map on a large-scale topographic map base (scale 1:12,000). Most of the mapping was from low-altitude aerial photographs provided by the BLM, with field checking of important areas. The mapping included plotting bedrock outcrops of all lithostratigraphic units (Fountain, Ralston Creek, Morrison and Dakota formations), and morphostratigraphic units (landslide, interlandslide valley fill, terrace, alluvial, and colluvial deposits) that cover the bedrock. The locations of mines, wells, and quarries were also plotted on the map. From the surficial map, a paleontologic resources map was compiled that classifies the various fossiliferous exposures by their degree of paleontologic importance. Class 1 exposures are outcrops of any size with known dinosaur quarries or fossil type localities, and are the areas of highest paleontologic interest. Class 2 exposures are large outcrops of potentially fossiliferous rocks but with no developed quarries or type localities. These exposures have high research potential. Class 3 exposures are scattered, small outcrops of potentially fossiliferous rocks, which have moderate to low paleontologic research potential. Class 4 exposures include outcrops of unfossiliferous rocks or areas covered by extensive Quaternary deposits and have very little to no paleontologic research interest.
Class 1 and 2 exposures were recommended for Research Natural Area designation. In addition, the extensive landslides in the area were recommended as Areas of Critical Environmental Concern due to their value to research and education. The 2 maps have been used extensively in the planning of a visitor's center and interpretive trails, have helped researchers locate new fossil sites, and have helped land managers control disturbances from gravel quarrying, road building, and mining. The map has also been used to negotiate land transfers and purchases of private lands to include additional Class 1 outcrops.

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United States Department of the Interior, National Park Service