Uplift of the Teton Range is primarily controlled by displacement across the range-front Teton normal fault. The Tetons comprise the footwall block while the hanging wall encompasses Jackson Hole valley and a portion of the Snake River. Relative to the rest of the Rocky Mountains, the Tetons experienced the majority of uplift very recently, substantiating the need for a detailed investigation integrating structural analysis and bedrock thermochronometry. New low-temperature cooling ages are documented in three vertical transects across the Teton Range and at low elevations parallel to the Teton fault. Samples adjacent to the Teton fault are consistently young (~9 Ma) and represent a minimum estimate for the onset of Teton fault-related uplift. Modeling of time-temperature histories supports a ~9-11 Ma onset of rapid uplift, indicating that the Teton fault likely originated as a Basin and Range-type structure. A maximum throw of ~8 km occurs proximal to the Grand Teton, while the average throw for the entire ~100 km along-strike fault length is ~3.3 km. Thus, the geometry of the Teton fault is comparable to traditional scaling relationships dictating a correlation between fault length and displacement. Inversion of the typical (U-Th)/He (AHe) and fission track (AFT) relationship in a few of the Teton Range samples is a result of intense zoning, primarily in apatite from Precambrian layered gneisses. Nonetheless, both the AHe and AFT ages consistently indicate slight differential uplift of the Tetons between the Late Oligocene and Middle Miocene. HeFTy models indicate that doming of the Precambrian-Paleozoic unconformity occurred prior to ~50 Ma. However, by ~15 Ma, rapid cooling of the Mount Moran section essentially "flattened" the unconformity. Thus, the modern domed shape is a result of displacement across the Teton fault, allowing the unconformity to be used as a proxy for fault deformation. Moreover, reconstruction of the unconformity and volume calculations produced an average depth to incision of ~0.3 km and a long-term erosion rate of 0.18 mm/yr. Compared to the long-term uplift rate of 0.22 mm/yr, this provides a quantitative explanation for the modern Teton topography. / Master of Science

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The evolution of mountain landscapes is controlled by complex interactions between large-scale tectonic, surficial and climate conditions. Dominant processes are attributed to creating characteristic features of the landscape, but topographic features are the cumulative result of coupled surficial processes, each locally effective in a different climate or elevation regime. The focus of erosion by glacial, fluvial, or mass wasting processes is highly sensitive to small changes in boundary conditions, therefore spatial and temporal variability can be high when observed over short time scales. This work evaluated methods for dissecting the history of complex alpine landscapes to understand the role of individual processes influenced by changing climate and underlying bedrock. It also investigated how individual and combined mechanisms of surficial processes influenced the evolution of topography in the Teton Range in Wyoming. Detrital apatite (U-Th)/He thermochronology and cosmogenic radionuclide erosion rates were applied to determine spatial and temporal variability of erosion in the central catchments of the range. Spatial variability existed between the glacial and fluvial systems, indicating that sediment erosion and deposition by these processes was controlled by short-term variability in climate conditions. Effective glacial incision also controlled other processes, specifically enhancing rock fall activity and inhibiting fluvial incision. Short-term erosion rates were highly variable and were controlled by stochastic processes, particularly hillslope failures in response to slope oversteepening due to glacial incision and orientation and spacing of bedrock fractures. Erosion rates averaged over 10 ky time scales were comparable to long-term exhumation rates measured in the Teton Range. The similarity of spatial erosion patterns to predicted uniform erosion and the balance between intermediate and long-term erosion rates suggests the landscape of the Teton Range is approaching steady-state, but frequent stochastic processes, short-term erosional variability and coupled processes maintain rugged topographic relief. / Ph. D.