Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 18 of 18 for “"Point-bar"”.
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Process Sedimentology and Three-Dimensional Facies Architecture of a Fluvially Dominated, Tidally Influenced Point Bar: Middle McMurray Formation, Lower Steepbank River Area, Northeastern Alberta, Canada
… a fluvially dominated, tidally influenced point bar that experienced strong seasonal variation in river discharge. Annual fluctuations between river-flood stage and low-flow stage are responsible for the deposition of fluvially dominated sand beds alternating with brackish, tidally …
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The influence of channel-skewed bedforms on flow structure in a high-amplitude meandering channel
… boundary configurations of ripples, dunes, and bars along alluvial rivers. The instantaneous boundary morphology heavily influences the local flow structure, especially within meander bends, and the temporal evolution of these interactions determines the behavior of channels as they migrate …
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Depositional Architecture of Confined Meander Belt Deposits, Lower Cretaceous Grand Rapids Formation, east-central Alberta
… due to the large scale of channels and point bars imaged in seismic data. The fine-grained character of the meander belt is likely a result of: (1) a propensity for muddy counter point bar preservation at the expense of sandy point bar deposits; and (2) limited supply of sand to the …
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Heterogeneity, paleohydrology, and 3D facies architecture of ancient point bars, Ferron Sandstone, Notom Delta, South-central Utah
… within one depositional unit (such as a unit bar or channel belt) and can be used to infer channel flow and bar migration patterns. Four hundred and eight paleocurrent directions were integrated with grain-size measurements to reconstruct the 3D facies architecture of the ancient channel …
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The Influence of Fluvial Geomorphic Processes on Spatial Patterns of Forest Primary Succession
… primary successional forests along depositional point bars at river bends of the Bogue Chitto River, Louisiana, USA and on nine additional rivers in the southeastern US. I hypothesized that geomorphic processes associated with river planform cause patterns of tree species to vary predictably …
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Stream Habitat Characterized by Stage -Specific Flows and Three-Dimensional Geomorphological Complexity: Development of Ecological Criteria for Stream Restoration Design
… pool, glide, riffle with and without a raceway, point bar platform, and a lateral area in the lee of an obstruction. At high-flow stages where flows are contained in the active channel, four habitat units were identified as the channel thalweg, deflection eddy, expansion eddy, and local hydraulic …
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Sedimentary Characteristics and Nutrient Sequestration of Embanked Floodplains Along the Lower Mississippi River, Mississippi and Louisiana
… sub-environments including levee backslope, point-bar and backswamp, taken from the Lower Mississippi floodplain were analyzed for their organic matter (OM), carbon (C), nitrogen (N), phosphorus (P), magnetic susceptibility, and particle size with depth. High concentrations of C, N, and OM …
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An investigation of information display variables utilizing computer-generated graphics for decision support systems
… four different graph reading tasks consisting of point-reading, point-comparison, trendreading, and trend-comparison. In each task, line, point, bar, and three-dimensional bar graphs were investigated under two levels of task complexity, and two levels of coding (color and black-and-white). The …
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Interactions between currents and the spatial structure of aquatic vegetation
… experiments in which vegetation was added to the point bar of a stream meander during base flow. During the next flood event, this vegetation proved to be destabilizing as a portion of the vegetation scoured away and the cross section of the open channel showed clear patterns of erosion. The …
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The fluvial dynamics of confluent meander bends
… of the bend, inducing bed scour and inhibiting point-bar development. The high junction angle forces the tributary flow to abruptly realign to the orientation of the downstream channel, initiating a counter-rotating helical cell over the outer portion of the bend. Two surface-convergent helical …
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The sedimentology and petrology of the new red sandstone of the Elgin Basin, North East Scotland
… during the Triassic is dominated by aeolian barchan dunes although minor point bar, playa and floodplain deposits were' present. A caliche, horizon terminates deposition during the late Triassic. The sediments were derived from the south and south west from an Old Red Sandstone, Moinian and …
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Stratigraphy, Two-Dimensional Geometry and Internal Sedimentary Structure of Hyaloclastite Deposits in the Siða Formation, SE Iceland; Implications for Mechanisms of Emplacement
… of a hyaloclastite lens at Location 2 resembles point bar formation in a braided river channel, while small-scale cross- and trough-cross bedding indicates the development braided river bars. The geometries of the lensoid hyaloclastite units are comparable to those of fluvial channels documented …
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High Resolution Facies & Architectural Analysis of a Tributive, Basal Terrace of a Ferron Compound Incised Valley
… of the facies architecture of a point bar in the basal, fluvial unit and a tidal channel/flats complex in the upper, estuarine unit. A marked, vertical increase in tidal influence and an accompanying landward shift in facies between these two units suggest Valley 3 is …
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Comportamiento morfodinámico e hidrosedimentológico de un sistema de canales mesomareales del estuario de Bahía Blanca
… en ellos. Los rasgos morfológicos (dunas, point bar, bancos elongados), junto con los datos de corrientes indican la dominancia del reflujo. En consecuencia, el modelo de circulación de sedimento, con máximos valores de transporte en El Alambre (0,08773 gr cm-1 seg-1), revela una …
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Remote sensing of river kinematics and their expression in the modern and ancient stratigraphic record
… while illustrating the potential importance point bar erosion during low discharge conditions. Floods are shown to have a significant impact on net stratigraphic preservation and represent a significant fraction of deposits preserved within the channel over the 7-year period. Chapter 4 shifts …
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Interpretation of coarsening upwards hemicycles in the Upper Paleozoic rocks of South-central West Virginia
… with thick subunits), b) distributary mouth bar (convex top sandstones and siltstones), c) interdistributary bay (mainly grey mud-clay rocks, and aphanic, highly fossiliferous limestones with abundant <em>Spirorbis</em>, ostracodes), d) levee-splay (silt shale, sandy siltstone with abundant …
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Stratigraphy, sedimentology, and depositional environments of the Hell Creek Formation (Late Cretaceous) and adjacent strata, Glendive area, Montana
… Creek.</p> <p>Sandstones are interpreted to be point bar deposits of meandering distributary channels. Sandy siltstones are natural levee deposits. Shales are interdistributary floodbasin, lake, and abandoned channel deposits. Lignites are swamp and freshwater marsh deposits. The meander belts …
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The sedimentology of bedforms to barforms within tidally-influenced fluvial zones (TIFZx): lower Columbia River, OR/WA, USA, and the lower Chehalis River, WA, USA
… sedimentary architecture of the bedforms and barforms in these systems. These results will be used to further the current understanding, and sedimentological models, of single- and multi- threaded TIFZs. New data are presented defining the large-scale TIFZ hydraulic environments along the …