the ground-water system was studied in Burnout Canyon, Northern Wasatch Plateau, Utah to provided hydrogeologic information relative to the impacts of longwall coalmining induced subsidence. The longwall panels of coal are overlain by approximately 600 feet of interbedded sand, silt, and shale. The water-bearing zones are comprised of local 1enticular sand lenses. Well analysis and locations of springs indicated that multiple ground-water systems are operating within the study area.A modular three-dimensional, finite-difference flow model (MODFLOW) was used to simulate the multiple water-bearing zones and associated hydrostratigraphy above the mine. The model was used to assess the distribution of head over space both pre- and post-subsidence, using absolute heads and measured values of mine-inflow for model calibration. Longwall retreat was simulated with two model runs, each representing a new face position. Model calibration indicated that spatial head distributions were affected by subsidence. / Department of Geology

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.

Though stratigraphic correlations are abundant in the Cordilleran basin-fill, they rarely include along-strike transects providing a spatio-temporal sense of deformation, sediment-supply and subsidence. A new, high-resolution, regional strike-correlation of the Castlegate Formation reveals progressive northward-growth of the San Rafael Swell during two embryonic episodes of Laramide-style deformation in central Utah. The intrabasinal deformation-events produced gentle lithospheric-folding punctuated by erosional-truncation of upwarped regions. The earliest episode occurred at 78 Ma in the southern San Rafael Swell likely causing soft-sediment deformation and stratal-tilting. Following this the alluvial-plain was leveled and rapid, extensive-progradation took place. A second episode, at 75 Ma, where deformation was focused in the northern San Rafael Swell, also caused sediment-liquefaction and erosional beveling. The stratal-tilting and sediment-liquefaction is attributed to seismicity induced by basal-traction between a subducting flat-slab and continental-lithosphere. The south-to north time-transgression of uplift is spatio-temporally consistent with NE-propagation of an oceanic-plateau subducted shallowly beneath the region.