Geologic mapping, facies analysis, sedimentary petrography, and detrital zircon analyses of undivided eastern Uinta Mountain Group stratigraphy are presented to better understand the depositional environments and tectonic setting of the Uinta Mountain Group basin. Subdivided units have been modified and correlated from previous work and include the Red Pine Shale, Hades Pass, Crouse Canyon, Outlaw Trail, and Diamond Breaks formations. Three lower-order maximum flooding surfaces associated with the lower Outlaw Trail formation, lower Hades Pass formation, and Red Pine Shale are interpreted. The relative magnitude of each lower-order transgression increases up section along with increasing diversity of palynomorph assemblages found in organic shale intervals. Six facies associations exist within the section and are interpreted as braided fluvial conglomerate, braided fluvial sandstone and conglomerate, braided fluvial sandstone, low-energy braided fluvial sandstone, mudflat, and offshore depositional environments. Both marine and non-marine interpretations are plausible for mudflat and offshore environments; however, previous interpretations of correlative Red Pine Shale exposures suggest a marine environment. The coarsest fluvial environments are restricted to the northern half of the study area and likely coincide with proximity to a tectonically-active northern basin margin. Paleocurrent analysis and the restriction of some subaqueous deposits to the north show northward-dipping depositional slopes, which suggest a tectonic control. Provenance work suggests three general sediment sources existed: an eastern source where ~1.1 Ga and lesser ~1.4 Ga detritus dominate, an east-northeastern source where ~1.8 Ga detritus dominate, and a north-northeastern arkosic source where ~2.7 Ga detritus dominate. Results suggest that during lower-order lowstands, sediments derived from eastern sources dominate. Higher concentrations of ~1.8 Ga and ~2.7 Ga detritus is likely coincident with proximity to the northern basin margin. During lower-order highstands, eastern or northern sources may dominate; northern sources appear more prominently within the Outlaw Trail formation, while eastern sources appear more prominently within the Red Pine Shale. Reasons for this may be linked to the magnitude of the transgressive interval sampled. These relationships, in conjunction with observations of previous studies, suggest the eastern Uinta Mountain Group was deposited in a half-graben style rift, a strike-slip basin, or some combination of the two.

This study investigated alarm calls given by Uinta ground squirrels (Spermophilus armatus) in the presence of a ground predator. I observed predator responses of 18 groups of three to four squirrels each for an average of three trials apiece. r~y objectives were: (1) to describe prey-predator interactions resulting in alarm calls, and (2) to test the following hypotheses: 1. Each Uinta ground squirrel (by sex and age) has an equal probability of giving an alarm call at any time of the season. 2. All Uinta ground squirrels are equally likely to call regardless of their distance to a burrow, closest conspecific, and the predator. 3. Alarm calls are as likely to occur in the search stage of predation as in the pursuit stage. 4. Callers and noncallers are equally vulnerable to predation. I found that: ( 1) each Uinta ground squirrel (by sex and age) in the experimental population had an equal probability of giving an alarm call in the presence of a predator through the season, (2) callers and noncallers were equally close to burrows at the time of the call, (3) the caller was typically located farther away from its closest conspecific than noncallers at the time of the cal l, (4) the caller was significantly closer to the predator than were noncallers at the time of the call, (5) alarm calls occurred significantly more often in the pursuit stage of predation than in the search stage, and (6) noncallers suffered significantly more predation than did callers. There appeared to be little risk and energetic cost associated with calling. Squirrels that called usually were being pursued by the predator and were very close to a burrow when they called. The callers had little to lose and could increase their inclusive fitness by warning relatives of the presence of danger. This study dealt only with responses to ground predators. Squirrels are likely to respond differently to avian predators. It is suggested that responses of animals to avian and terrestrial predators should vary with the potential threat that the predator poses. The apparent inhibition of secondary calls is discussed. Once animals are aware of the presence of danger, there is no need for another animal to repeat the message and reveal its location to the predator.

Thesis (M.S.)--Brigham Young University. Dept. of Geological Sciences, 2007. / Includes map in back cover pocket. Includes bibliographical references (p. 29-30).

Detailed mapping (1:24,000), measured sections, and clast counts in conglomerates of the Duchesne River Formation and Bishop Conglomerate in the Vernal NW quadrangle in northeastern Utah reveal the middle Cenozoic stratigraphic geometry, the uplift and unroofing history of the eastern Uinta Mountains, and give evidence for the pulsed termination of Laramide uplift. The Unita Mountains are an EW-trending reverse fault bounded and basement-cored, Laramide uplift. The oldest unit of the Duchesne River Formation, the Eocene Brennan Basin Member, contains 80-90% Paleozoic clasts and <20% Precambrian clasts. Proximal to the Uinta uplift the conglomerates of this member are dominated by Paleozoic Madison Limestone clasts (70-90% of all clasts). Farther out into the basin, Paleozoic clasts still dominate in Brennan Basin Member conglomerates, but chert clasts are more abundant (up to 43%) showing the efficiency of erosion of the carbonate clasts over a short distance (~5 km). Conglomerates in the progressively younger Dry Gulch Creek, Lapoint, and Starr Flat members show a significant upward increase in Precambrian clasts with 34-73% Uinta Mountain Group and 8-63% Madison Limestone. Duchesne River Formation has a significant increase in coarse-grained deposits from the southern parts of the quadrangle (20-50% coarse) to the northern parts (75% coarse) nearer the Uinta uplift. The lower part of the Duchesne River Formation exhibits a fining upward sequence representing a tectonic lull. Clast count patterns show that pebbly channel deposits in the south maintain similar compositions to their alluvial fan counterparts. To the north, the fine-grained Lapoint and Dry Gulch Creek members of the Duchesne River Formation appear to pinch out completely. This can be explained by erosion of these fine-grained deposits or by lateral facies shifts before deposition of the next unit. Starr Flat Member conglomerates were deposited above Lapoint Member siltstones and represent southward progradation of alluvial fans away from the uplifting mountain front. Similarities in composition and sedimentary structures have caused confusion surrounding the contact between the Starr Flat Member and the overlying Bishop Conglomerate. Within the Vernal NW quadrangle, we interpret this contact as an angular unconformity (the Gilbert Peak Erosion Surface) developed on the uppermost tilted red siltstone of the Starr Flat Member sometime after 37.9 Ma. Stratigraphic and structural relationships reveal important details about the development of a Laramide mountain range: 1) sequential unroofing sequences in the Duchesne River Formation, 2) progradation of alluvial fans to form the Starr Flat Member, 3) and the unconformable nature of the Gilbert Peak Erosion Surface lead to the conclusion that there were at least 3 distinct episodes of uplift during the deposition of these formations. The last uplift episode upwarped the Starr Flat Member constraining the termination of Laramide uplift in the Uinta Mountains to be after deposition of the Starr Flat Member and prior to deposition of the horizontal Bishop Conglomerate starting at about 34 Ma. This, combined with 40Ar/39Ar ages of 39.4 Ma from the Dry Gulch Creek and Lapoint member, show that slab rollback related volcanism was occurring to the west while the Uinta Mountains were being uplifted on Laramide faults. These new 40Ar/39Ar ages constrain the timing of deposition and clarify stratigraphic relationships within the Duchesne River Formation; they suggest a significant unconformity of as much as 4 m.y. between the Duchesne River Formation and the overlying Bishop Conglomerate, which is 34-30 Ma in age, and show that Laramide uplift continued after 40 Ma in this region.

The headwaters of the Bear River in the Uinta Mountains of Utah provide a good setting in which to examine the influence of geological materials on stream chemistry. Ionic contributions to the stream-water from soils, vegetation, and the atmosphere generally are sparse enough that they do not mask the geologic contributions. Samples from 37 sites on the four major headwater streams and several minor tributaries were examined geochemically. Data derived from the samples allowed the construction of a hydrogeochemical weathering model specific to the study area. A significant feature of this model is that carbonic acid is the dominant chemical agent involved in geochemical weathering. The aim of this study was to examine the geologic influences on river chemistry. However, atmospheric contributions dominate the hydrochemistry through at least the first 10 kilometers of stream length for the easternmost three of the four major headwater streams. Except for the atmospheric contribution, surface-water chemistry is dominated by the groundwater chemistry, which is indelibly marked by the lithology the groundwater passes through. Other geologic factors in the study area that appear to influence groundwater chemistry, and hence stream chemistry, are the glacial till and outwash deposits and a major zone of east-west trending high-angle thrust faults. A technique for estimating the hydrochemistry of the groundwater based on surface-water chemistry and flow measurements was developed in this study.

The objectives were (1) to relate terrestrial vertebrate responses to the management practices used for lodgepole pine forests within the Barometer Watershed, Mountain View Ranger District, Wasatch National Forest, Utah . (2) To correlate terrestrial vertebrate densities or frequencies with community types, edge, major forest stand structures , and (3) to propose management plans to manipulate densities of major vertebrate species in a predetermined manner. The study was conducted between 1973-1975 and provides a detailed description of forest vegetation for 53 lodgepole pine (Pinus contorta) stands. For each of these stands, a complete summary is provided of tree populations, coverage, and frequency of major vascular undergrowth species . Eight lodgepole pine forest community types are defined. A key is provided for identification of each community type and its anticipated habitat type. The relationships between densities of major vertebrate species, forest communities, and major forest stand structures are described. Big game utilization of ecotones created by mountain meadows and the lodgepole pine forest are discussed. In addition, the response of selected small mammal and big game species to clearcut size is provided. Important research findings were: (1) In the lodgepole pine forest most vertebrates exhibit preferences for specific community types. (2) Due to the broad definition of present habitat classifications, limited predictions can be made about the general response of wildlife populations on most sites. (3) The use of park-like openings and associated peripheral timber hy big game animals is closely associated with community type, edge configuration, and historical travel lanes. (4) An abundance of downed woody material enhances big game calving and resting areas. (S) The number of bird species is closely associated with understory biomass and diversity. (6) Management schemes that speed up the rotation of lodgepole pine overstories eliminate certain vertebrate communities associated with the final successional stages. The following specific recommendations for overstory removal are suggested. (1) Timber sales should be developed by drainage, with longterm objectives that insure the distribution of a variety of communities within a drainage. (2) The addition of major stand structure information should be included in habitat classification systems. (3) Timber sales should be designed with irregular edges and buffers of standing timber which provide cover and concealment. (4) Moist sites and relic areas, representing the final stages of succession, should be planned into the overall drainage sale philosophy. {5) In relatively undisturbed areas, vehicular travel should be prohibited following overstory removal.

The Shiras moose, Alces alces shirasi, and its winter habitat on the north slopes of the Uinta Mountains in Utah were studied from August, 1969, to July, 1971 to determine the food requirement for moose, the key browse species during the winter months, the acreage, density and utilization of the key browse species, and their carrying capacity for moose. It was determined that an average adult moose had a daily food requirement of 19,133 kilocalories. The key browse species for moose were Salix drummondiana and S. geyeriana. These two species accounted for 92.0 and 4.7 percent respectively of all feeding occurrences on browse species recorded. According to density analyses, S. drummondiana made up 59 percent of the vegetation and S. geyeriana 31 percent. The caloric capacity of the key browse species for moose body maintenance was slightly more than 1.5 billion kilocalories. The moose carrying capacity of the key browse species on the winter range was 80,030 moose days or 445 adult animals for a period of six months. Specifically, the carrying capacity, based on a weighted caloric requirement and annual classification counts, would be 115 bulls, 250 cows, and 156 calves for a period of six months on the winter range.

Geologic mapping of the Jessen Butte 7.5 minute quadrangle and the gathering of structural data throughout the quadrangle was used to determine the paleostress regime during the Laramide Orogeny along the north flank of the Uinta Mountains. The Henrys Fork thrust fault and the Uinta thrust fault are major north bounding faults and within the Jessen Butte quadrangle these faults transfer deformation from one to the other. The Jessen Butte thrust fault is a fault splay that splits off from the Henrys Fork thrust fault. Complex fold geometries were created by the interaction of the faults. Bedding plane orientation, mode I fracture orientation, and fault kinematic indicators were measured throughout the quadrangle. A shortening direction to the NE was recorded by all of these different types of measurements, which match with the proposed regional stress field for the Laramide Orogeny. In a few cases N-S shortening was also recorded in the data, which may be from the local stresses in the area due to pre-existing weaknesses in the basement rocks. Finally, for creation of the cross sections, a positive flower structure model best fit the fold geometry of the rocks in the Jessen Butte quadrangle. This type of fold forms in areas which experience strike-slip motion. This suggests that, at least along the north side of the Uinta Mountains, deformation occurred in a uniform stress field during the Laramide Orogeny, with some influence from the pre-existing weakness inherited from the Precambrian basement.

The present work is a general survey of the vegetation of the Utah portion of the Dinosaur National Monument with special emphasis on some of the ecological aspects of the area. The vegetation ranges from xerophytic plant communities of the lower elevations to mesophytic communities of the higher elevations. Hydrophytic plant communities are also present to a limited extent along the Green River and where seeps or springs arise. Soils vary from fine clay to coarse gravel. The dividing lines between formations is often marked by extreme differences in soil type. During the author's first collecting trip into the Monument in April 1955 the possibility of correlations between geological formations and vegetation was suggested by the occurrence of certain plant species on some of the formations. The presence of a well defined geological section in a relatively short distance makes it possible to determine if such correlations exist.

Outcrop and petrographic studies of the Eocene Green River and Colton formations in the Uinta basin, Utah, document the facies architecture and heterogeneity characteristic of lacustrine reservoirs. A southwest-northeast transect of Eocene strata in the Uinta basin records three main marginal lacustrine depositional environments: fluvial, deltaic, and wave-dominated. Heterogeneity exists between and within individual depositional systems. Reservoir rocks of Outcrops One and Two (the flu vial facies of the Colton Formation and the deltaic facies of the Green River Formation, respectively) consist of 2 to 18 m thick lenticular, tabular, or undulatory channel-fill, distributary channel, and distributary mouth bar deposits that are partially to entirely compartmentalized, or encased, by mudstone units. These reservoir analog intervals are dominated by large­ scale heterogeneity, in that sand bodies show a variety of connectivity and lateral continuity. Small-scale heterogeneity exists within these sand bodies in the form of mud chip lag surfaces, large mud clast horizons, and discontinuous finer-grained beds. These features add complexity to the systems by reducing flow transmissibility or acting as flow baffles. The complex heterogeneity characteristic of these reservoir analogs confirms the need for detailed reservoir characterization studies on all scales in order to improve exploration and production efficiency in such systems. Outcrop Three (the wave-dominated facies of the Green River Formation) is dominated by thinner (2 to 4 m) tabular and laterally extensive offshore bar deposits that are compartmentalized by mudstone units. Large-scale heterogeneity is minimized in these reservoir analogs, in that sand bodies exhibit excellent lateral continuity and less complex amalgamation. Therefore, documentation of the smaller-scale heterogeneities (similar to those mentioned in the previous two outcrops) is necessary to better address exploration and production potential in these types of reservoirs. Data collected in this study were utilized in geostatistical simulations and fluid flow models in an attempt to document the effects of reservoir heterogeneity on hydrocarbon exploration and production efficiency in lacustrine basins. Further studies of this type are necessary if predictable classification systems and hierarchies of bounding surfaces are to be derived for lacustrine reservoirs. (152 pages)