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The Global ETD Search service is a free service for researchers
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Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
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Showing 1 to 7 of 7 (0.171 seconds)Spelling suggestions: "subject:"sedimentation anda deposition -- arizona."" "subject:"sedimentation anda deposition -- orizona.""
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Sedimentation studies in the vicinity of Willcox Playa, Cochise County, ArizonaPine, Gordon Leroy, 1938- January 1963 (has links)
No description available.
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Stratigraphy and depositional environment of the Colina limestone (lower Permian), southeastern ArizonaLyons, Timothy Williams, 1957- January 1989 (has links)
No description available.
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Stratigraphy and depositional history of the Pantano Formation (Oligocene-early Miocene), Pima County, ArizonaBalcer, Richard Allen January 1984 (has links)
No description available.
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The Hellhole Conglomerate: a study of a mid-Tertiary extensional basinWalsh, James Leo, 1960. January 1989 (has links)
No description available.
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A numerical model of watershed erosion and sediment yieldLopes, Vicente Lucio,1952- January 1987 (has links)
A physically based, distributed parameter, event oriented, nonlinear, numerical model of watershed response is developed to accommodate the spatial changes in topography, surface roughness, soil properties, concentrated flow patterns and geometry, and land use conditions. The Green and Ampt equation with the ponding time calculation for an unsteady rain is used to compute rainfall excess rates. The kinematic wave equations are used to describe the unsteady one-dimensional overland and channel flow. The unsteady and spatially varying erosion/deposition process on hillslopes and channel systems is described dynamically using simultaneous rates of sediment entrainment and deposition rather than the conventional approach using steady state sediment transport functions. To apply the model the watershed is represented by a simplified geometry consisting of discrete overland flow planes and channel elements. Each plane or channel is characterized by a length, width, and a roughness parameter. For channel elements, a cross-section geometry is also needed. A modular computer program called WESP (Watershed Erosion Simulation Program) is developed to provide the vehicle for performing the computer simulations. Rainfall simulator plots are used to estimate infiltration parameters, hydraulic roughness, and soil erodibility parameters for raindrop impact and overland flow. The ability of the model to simulate watershed response (hydrograph and sedigraph) to a variety of rainfall inputs and antecedent soil moisture conditions is verified using data collected on two small watersheds. The good agreement between the simulated watershed response and the observed watershed response indicates that the governing equations, initial and upper boundary conditions, and structural framework of the model can describe satisfactorily the physical processes controlling watershed response.
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The depositional environment and petrographic analysis of the Lower Cretaceous Morita Formation, Bisbee Group, southeastern Arizona and northern Sonora, MexicoJamison, Kermit January 1983 (has links)
No description available.
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Stratigraphy and Depositional History of the Pantano Formation (Oligocene-Early Miocene), Pima County, ArizonaBalcer, Richard Allen January 1984 (has links)
The Pantano Formation comprises 1,250 m of alluvial, fluvial, lacustrine, and volcanic rocks deposited in a basin formed in response to regional extension during mid- Tertiary time in southeastern Arizona. During deposition, the locations and composition of sediment source areas varied as contemporaneous uplift occurred adjacent to the basin. The lower half of the formation was deposited as alluvial fans that prograded northward, westward, and southward; the upper half was deposited during southwestward retreat of alluvial fan deposition and the onset of lacustrine deposition. An andesite flow separates the two depositional regimes. Radiometric dates of 24.4 ± 2.6 m.y. B.P. for the andesite and 36.7 ± 1.1 m.y. B.P. for a rhyolitic tuff disconformably underlying the formation indicate that deposition occurred during Oligocene to early Miocene time. Proper stratigraphic sequencing and description, paleocurrent analysis, and gravel provenance study aided in understanding the depositional history of the formation.
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