The lower continental slope of Morocco’s west coast consists of Triassic-age salt manifested in the form of diapirs, tongues, sheets, and canopies, and both extensional and compressional structures that result from salt movements. Salt diapirism and regional tectonics greatly influenced a broad spectrum of depositional processes along the margin. Mapping of a 1064-km2 (411-mi2) seismic survey acquired in the Safi Haute Mer area reveals that Jurassic to Holocene salt mobilization has induced sedimentation that manifests itself in gravity slumps and slides and debris flows. An east-west–trending structural anticline located downdip of the salt-influenced region, was activated during the Atlas uplift (latest Cretaceous) and shaped much of the lower continental slope morphology from Tertiary time until present. The largest of the mass transport deposits (MTC) is a 500-m (1640-ft)-thick Cretaceous-age unit that spans an area of up to 20,000 km2 (7722 mi2). Seismic facies composing the MTC are (1) chaotic, mounded reflectors; (2) imbricated continuous to discontinuous folded reflector packages interpreted to represent internal syn-depositional thrusts; and (3) isolated, thick packages of continuous reflectors interpreted to represent transported megablocks (3.3 km2 [1.3 mi2]). The latter show well preserved internal stratigraphy. The MTCs originated from an upslope collapse of a narrow shelf during the earliest phases of the Alpine orogeny. Seismic geomorphologic analysis of the non-salt-deformed sections reveal numerous linear features that are interpreted as migrating Mesozoic-age deepmarine sediment waves. Three styles of sediment waves have been identified. These include: (1) type J1—small (less than 17 m thick) and poorly imaged, Jurassic in age, ridges that have wavelengths of up to 12 km and crest-to-crest separations of less than 1 km; (2) type K1—early Aptian constructional sediment waves (~110 m thick) that appear to show some orientation and size variations which suggest an influence on currents by salt-influenced seafloor topography, and (3) type K2—latest Albian and earliest post-Albian sediment waves exhibiting wave heights of 40 m and crest-to-crest separations of 1 km, that are continuous across the entire study area and show evidence of up-slope migration.

Hydraulic and morpho-sedimentary differences between pools and riffles have always intrigued fluvial geomorphologists. Surprisingly, earlier explanations of pool-riffle morpho-sedimentology dynamic focus too exclusively on hydraulic patterns and neglect analysis of sediment transport. Understanding the mechanisms governing pool-riffle morpho-sedimentary dynamics, such as the sediment transport patterns represent a big challenge in fluvial geomorphology, considering the stochastic nature of bedload transport in gravel-bed rivers. The main objective of this thesis is to understand the two-dimensional relationship between hydraulic patterns, sediment transport patterns and morpho-sedimentary changes in pool-riffle sequences and to use these insights to understand how pool-riffle sequences maintain their form over time. / This thesis is organized into four chapters. These chapters analyze hydraulic, sediment transport and morpho-sedimentary measurements collected on a riffle-pool-riffle sequence of the Des Coeurs river during seven controlled experimental floods. Chapter 2 tests the velocity reversal hypothesis (Keller, 1971), with results demonstrating that no velocity reversal was observed in the field, for peak flow up to 123% of the bankfull discharge. Chapter 3 demonstrates the existence of a bedload transport reversal: below 60% of bankfull discharge, sediment transport on the riffle exceeds transport in the pool; as discharge increased, more sediment was exported from the pool than imported, thereby maintaining the pool. Chapter 4 demonstrates that the bedload transport reversal is caused by the spatial heterogeneity of the sediment transport patterns (sediment supply, particle displacements and sediment sorting), which underlies the importance of developing two-dimensional bedload transport formulae. Chapter 5 tests the two-dimensional applicability of well-known bedload transport formulae developed in a one-dimensional environment. None of the formulae could be applied with accuracy in a two-dimensional environment. However, site-specific calibration considerably improves bedload transport rate and grain-size distribution prediction. / This thesis improves the understanding of the morpho-sedimentary dynamics of pool-riffle sequence; it argues that a purely hydraulic view of pool-riffle sequence is insufficient to understand their stability. It explains pool-riffle maintenance as a result of a bedload transport reversal caused by the spatial heterogeneity of the sediment transport patterns, and raises the importance of acquiring two-dimensional sediment transport data to improve two-dimensional bedload transport formulae.

Bibliography: v. 1, leaves 127-152 / 2 v. : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Geology and Geophysics, 1986

Zugl.: Berlin, Techn. Univ., Diss., 2005

Thesis (M.S.)--University of Nevada, Reno, 2006. / "December, 2006." Includes bibliographical references (leaves 104-108). Online version available on the World Wide Web.

Thesis (Ph.D. - Hydrology and Water Resources)--University of Arizona. / Includes bibliographical references (leaves 112-119).

Thesis (B.S.)--University of Missouri, School of Mines and Metallurgy, 1912. / One folded map inside back cover. The entire thesis text is included in file. Typescript. Illustrated by author. Title from title screen of thesis/dissertation PDF file (viewed April 20, 2009) Includes bibliographical references.

Thesis (M.S.)--Texas State University-San Marcos, 2007. / Vita. Appendix: leaves 65-67. Includes bibliographical references (leaves 68-75).

Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographic references (leaves [146]-152).

Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (leaves [136]-147).