INVESTIGATIONS INTO THE MORPHOLOGY AND SPATIAL DISTRIBUTION OF HOODOOS AT GOBLIN VALLEY STATE PARK, EMERY COUNTY, UTAH

The primary attraction at Goblin Valley State Park (Emery County, UT) is the array of interestingly shaped and excellently exposed hoodoos, locally called goblins, formed within the Jurassic Entrada Sandstone.

The typical goblin consists of a spherical or oblong cap of resistant sandstone supported by a pedestal of softer siltstone and shale. Previous investigations have demonstrated the importance of spheroidal weathering, concentrated along near-vertical joint sets, in the development of the goblins. The ultimate fate of a goblin is for the sandstone cap to topple from its pedestal, a process which may be entirely natural or significantly accelerated by human activity. The primary goal of this study is to quantify spatial trends in goblin morphology and in the ratio of intact vs toppled goblins, in order to assess the potential human impact.

Field investigations during the fall of 2007 focused on an area of goblins rarely accessed by park visitors, located approximately 1.4 km south of the visitor parking area. Here basic morphomteric and GPS data were collected on goblins that lie along two nearly perpendicular transects. In addition, a study transect and preliminary GPS inventory of toppled goblins were started in the area most commonly accessed by park visitors (less than 0.5 km from the parking area). Data collection will continue in spring 2007.

Preliminary results indicate an important relationship between a local drainage divide and the overall occurrence of goblins. The west-facing cliff of Entrada Sandstone from which the goblins emerge coincides with the drainage divide between Goblin Valley and Well Draw.

Our preliminary transect data indicate a substantial difference in the percentage of intact goblins in the two areas. The two transects in the more distant area have an average of 15 goblin features per 100 m of transect, with over 50% of those features being intact goblins; the remainder are toppled goblins or remnant pedestals. The transect nearest the parking area has an average of 5 goblin features per 100 m of transect, with only 27% of those feature being intact goblins. Future studies are planned to further investigate this trend in hopes of determining if the difference is the result of natural variation in goblin density or the result of human disturbance.