Wellsville Mountain forms the extreme northern end of the Wasatch Range in northern Utah. It lies at the western margin of the Middle Rocky Mountain province and is bordered by valleys of the Basin and Range province. Many geologic investigations have been made in this region. Much of the Wasatch Range has been studied and mapped as well as parts of the Bear River Range, east of Cache Valley, and the Malad Range which extends north from Wellsville Mountain; however, the geology of Wellsville Mountain has not been studied or mapped in detail. Some reconnaissance mapping has been done and sections of Cambrian and Pennsylvanian formations have been measured on the western mountain front (Maxey, 1941; Williams, 1943), but little is known about the middle Paleozoic formations and the structural geology of the northern part of the mountain.

Several large sources of 1ce nuclei were identified for the Wasatch Weather Modification Experimental Area. When stable air masses remained over the area for several days, ice nuclei concentrations as large as 1750 per liter (measured at -20 C) were found at the surface. ConcentralX tions as large as 6000 per liter were measured with an airborne 1ce nuclei counter over the smelter industry of the Salt Lake Valley. Ice nuclei concentrations during storm periods were usually less than 3 per liter, indicating an excellent potential for increasing precipitation amounts over the Wasatch Mountains through the release of artificial ice nuclei. Ice nuclei measurements taken during and following seeding activities indicate that nuclei are not being trapped in the Cache Valley and are not being funnelled into areas upwind of the seeding generators. The measure ments also indicated that nuclei are getting into the seeding area, at least at the ground level. Residual lee nuclei were found in the experimental area--an average oF 7.5 hours for ground seeders and 4.6 hours For airborne seeders--following seeding activities. Stability, wind direction, and cloud top temperatures were found to be the meteorological conditions most closely related to ice nuclei concentrations although this could not be shown through the use of statistical tests.

Bryan Tikalsky Department of Geography Master of Science Mountain water resources are essential to those living along the Salt Lake City urban corridor. Water resource planners base their policy on twentieth century climate conditions and streamflow records. Often these records only account for a small amount of the natural variability in streamflow and climate. By utilizing dendrochronology this study seeks to better understand variability of streamflow in the Jordan River Drainage Basin over the last 828 years. A GIS model was used to identify potential sampling sites where tree growth would be sensitive to climate and factors affecting stream run-off. Over eighty samples from ancient limber pine (Pinus flexilis) and Douglas-fir (Pseudotsuga menziesii) were obtained to perform the reconstruction. Results indicate significant correlation between tree growth and streamflow. A multiple linear regression model created with tree-ring width as the predictor of October - March American Fork River streamflow explained 51.7% of streamflow variance. Analysis of the reconstruction indicates that present records do not adequately represent potential streamflow variability, and several droughts of greater severity and length occurred before the instrumental period.

An understanding of the interactions betnen vegetation and livestock grazing is of paramount importance to the welfare of the livestock industry. It is also important to know how these interactions affect the balance of the ecosystem. In general, observations of changes in vegetation provide an index for evaluating such interactions. Vegetation change is the main object of consideration in this paper. The study is concerned with some of the oldest pemanent native vegetation study plots in the Western United States. They are located on Horseshoe Flats of the Wasatch Plateau in Central Utah.

Facies and stratigraphic architecture right at the transition from marine to non-marine environments is poorly documented. In the Cretaceous outcrops of Utah, Star Point and Blackhawk Formations are well studied. The nature of spatio-temporal transition of these two Formations, in the deposition-strike orientation, remains undocumented. This study characterizes facies and stratigraphic complexity at the transition of the two Formations that crop out in depositional-strike orientation in the Wasatch Plateau. Data from outcrop including photomosiacs and measured sections demonstrate this complexity at a range of scales. The Star Point constitutes a shoreface environment. The Blackhawk constitutes a coastal-fluvial environment. In the northern part of study area, the transition from marine to continental strata is expressed by intertonguing succession. The dip-oriented outcrops show pinch-outs of two parasequences into coastal-plain deposits. This complexity decreases southward, the southern outcrops show a simple transition. At least two sequence boundaries are correlated across the outcrop belt.

Populations of Delphinium occidentale (Ranunculaceae)were monitored over two summers for the presence and dispersion of various life stages of several host specific phytophagous insects. Observations were made at several sites in the Wasatch National Forest east of Logan, Utah. Two species of larkspur aphid (Aphis rociadae and Kakimia wahinkae) were encountered. Although dispersal of alate individuals resulted in widespread infestation of the host plant population, aphids occurred initially on the same one or few plants at each site both springs. Little coexistence of the two species of aphid on the same plant was observed, perhaps because they partitioned the host plant resource according to light intensity under the incomplete aspen canopy. Several species of lepidopteran larvae, of uncertain host specificity, were observed. Two species (Autographa californica and pyrrhia expremins: Noctuidae) are known from cultivated host plants. Eggs of an unidentified geometrid (Lepidoptera) were located on the host plants in large numbers and their dispersion was analysed. The eggs were distributed nonrandomly over the host plant population, but attempts to further characterize the pattern were fruitless. Parasitism of the eggs by an unidentified hymenopteran was observed. Mortality of all larvae was high. Successful migration of larvae was not observed. Mature larvae were not sufficiently abundant to permit statistical study of pattern. Mature fruits were examined at the end of the growing season for larkspur maggots (Hylemya laxifrons). Maggots were found in 85 percent of the inflorescences sampled. Pteromalids (Hymenoptera) were also found in an apparently parasitic relationship with the maggots in the fruits. Maggots were not found in the surviving fruits of inflorescences infested with either species of aphid. Suggestions are given for future work.

Utah is one of the fastest growing states in the USA. Utah’s Wasatch Range Metropolitan Area (WRMA), where 80% of Utah’s population resides, is growing at unprecedented rates and has seen extensive urban landscape transformation in the last half century. Many of Utah’s agricultural lands, grasslands, and wetlands have been transformed into urban areas during this time. Local residents have watched and experienced these changes to their local environment, but without a clear understanding of the processes and impacts of urbanization. It is not until we study these landscapes from a spatial perspective and the time scale of decades that we can begin to measure the changes that have occurred and predict the impact of changes to come if current trajectories continue. In this dissertation research I worked with my research colleagues to provide a comprehensive analysis of the WRMA’s past land use changes and future land use trends. In doing so, we: (1) measured the rate, the magnitude, and the process of past urban growth; (2) compared the changes of irrigated agricultural lands and non-irrigated agricultural lands in relation to urban development; and, (3) predicted how future urban growth could occur under various policy scenarios. We found that several counties at the heart of the WRMA have reached the limits of their capacity for future urban expansion. Thus, increasing urban density and land use efficiency will be key aspects of addressing the WRMA’s future growth. Also, variations of growth trends exist among and within the ten counties located in the WRMA, so it is necessary to develop contextualized and localized growth management plans. Furthermore, past land use dynamics prove that irrigated agricultural lands are more affected by urbanization than non-irrigated agricultural lands, with evidence of increasing agricultural lands fragmentation. Agricultural lands have been and will likely continue to be the major land source for future urban development. Utah’s public has indicated it wants to preserve agricultural lands to maintain open space and preserve cultural heritage, but this will require political attention and actions focused on areas where these lands are particularly vulnerable in the face of urban growth trajectories. The overall dissertation provides quantitative measurement of Utah’s urban landscape transformation and a science-based foundation for crafting successful land use policies to help guide future growth of the WRMA.

Exhumed faults record the temperatures produced by earthquakes. We show that transient elevated fault surface temperatures preserved in the rock record are quantifiable through microtextural analysis, fault-rock thermochronometry, and thermomechanical modeling. We apply this approach to a network of mirrored, minor, hematite-coated fault surfaces in the exhumed, seismogenic Wasatch fault zone, UT, USA. Polygonal and lobate hematite crystal morphologies, coupled with hematite (U-Th)/He data patterns from these surfaces and host rock apatite (U-Th)The data, are best explained by friction-generated heat at slip interface geometric asperities. These observations inform thermomechanical simulations of flash heating at frictional contacts and resulting fractional He loss over generated fault surface time temperature histories. Temperatures of >similar to 700-1200 degrees C, depending on asperity size, are sufficient to induce 85-100% He loss from hematite within 200 pm of the fault surface. Spatially-isolated, high temperature microtextures imply spatially -variable heat generation and decay. Our results reveal that flash heating of asperities and associated frictional weakening likely promote small earthquakes (M-w approximate to -3 to 3) on Wasatch hematite fault mirrors. We suggest that similar thermal processes and resultant dynamic weakening may facilitate larger earthquakes. (C) 2017 Elsevier B.V. All rights reserved.

Phosphate deposits in the western United States have been the subject of considerable discussion in the last decade, and during the last few years much interest has been aroused in them. Phosphate was first discovered in this area in 1889, but it was not until 1906 that the United States Government took active interest in the study of these deposits. The investigation by the government of the occurrence of western phosphate was begun by Weeks and Ferrier (10), and later carried on by others. On December 9, 1908 the western phosphate reserve was created and many acres of land were withdrawn from all kinds of entry. In the summer of 1909 two parties were detailed by the United States Geological Survey to examine lands withdrawn from public entry.

Sagebrush shrubsteppe ecosystems have increasingly garnered attention as an endangered ecosystem. Ninety nine percent of all sagebrush ecosystems are thought to have been impacted by humans, and over 50% of grassland and shrubsteppe species are believed to be in decline. Most of the research on sagebrush ecosystems has been conducted at lower elevations and in large expanses of sagebrush. A considerable amount of sagebrush is found at higher elevations, often in meadows found within a forest matrix. The role of this high-elevation habitat is poorly understood. We conducted bird, small mammal, vegetation, and soil surveys in sagebrush-dominated mountain meadows within the Wasatch-Cache National Forest in northeastern Utah. Meadows ranged from 0.6 to 782 hectares in size and included an impressive list of associated plant species. We detected two sagebrush-obligate species and numerous shrubsteppe-associated species. Each species appears to respond to different habitat characteristics, but all species that showed a significant relationship with meadow size were more likely to occur in larger meadows. Many species showed no relationship with size, suggesting that while larger meadows were preferred by some species, small meadows could also play an important role as habitat. While sagebrush-dominated mountain meadows were important for some species, we also failed to detect a number of species of interest. In particular, Sage Thrasher, Sage Sparrow, and pygmy rabbit were not found within the study area. North American Breeding Bird data suggests that Sage Thrashers can be found nearby. It is likely that these birds are only found in large expanses, and none of our meadows were large enough to support them. Sagebrush-dominated mountain meadows appear to be an important supplement to large expanses of sagebrush shrubsteppe habitat, but are not substitutable for all species.