EVALUATING A GIS-BASED APPROACH TO PREDICTING THE SPATIAL DISTRIBUTION OF PERIGLACIAL DEPOSITS IN THE INTERIOR GREAT BASIN OF THE SOUTHWESTERN UNITED STATES

Previous researchers have described the existence and morphology of glacial landforms in the interior Great Basin (Blackwelder, 1931, 1934; Sharp, 1938; Currey, 1969; Waite, 1974; Piegat, 1980; Wayne, 1984; Osborn, 1990; Osborn and Bevis, 2001).  However, few studies have described periglacial deposits in the interior Great Basin (Heald, 1956; Kramer, 1962; Piegat, 1980; Wayne, 1984; Osborn, 1990; and Osborn and Bevis, 2001).  This is largely because many landforms are often un-recognized and because many mountains in the Great Basin are remote and offer poor access.

Using the methodology described by Frauenfelder and Kääb (2000), Hoelzle (1996), and Frauenfelder et al. (2001) within the ArcView environment, preliminary results accurately predicted the location of periglacial landforms in the Snake Range, east-central Nevada (Van Hoesen, 2003).  This initial modeling was validated by geomorphic field evidence; numerous rock glaciers, slopes exhibiting solifluction lobes, ice-wedge casts, and patterned ground were found in areas that were identified as “potential” zones for permafrost using a GIS.  Therefore, I utilized ArcView GIS, the SolarAnalyst extension, and digital elevation models for he Toiyabe, Toquima, White Pine, Shell Creek, and Monitor ranges in the interior Great Basin to evaluate the effectiveness of this tool for predicting the spatial distribution of periglacial deposits and prioritizing those areas with the greatest potential for discovery.  GIS modeling predicts numerous locations suitable for the development of periglacial features throughout these five ranges.  However, preliminary field investigations suggest that although there is indeed a strong relationship between the occurrence of relict periglacial features and incoming solar radiation, the prediction of potential sites is often complicated by topography.