The study of suspended sediment provides insights into the transport and accumulation of sediment in depositional basins. Past investigations have suffered, however, from a lack of methodology that can deal with the low concentrations of suspended sediment. The theory and method of three techniques to be used in the analysis of suspended sediment have been outlined. 1) VSA, provides a rapid, accurate and precise method of determining grain size distributions of low weight samples. The method is based on the solution to a set of equations that discretely define the increasing volume of a homogeneous sediment sample settling in an enclosed volume of water. The results are in terms of sedimentation diameters, a hydrodynamically sensitive property. 2) The Ag filter mount provides a fast technique for a low sample weight random oriented mount to be used in quantitative XRD analysis. The method has excellent precision and does not fractionate the mineral component due to their settling velocity. 3) Suspended sediment collectors have been used to measure the downward flux of sediment in the fjord environment. The traps have also provided a means to calculate the natural settling velocity of flocculated or otherwise enhanced particle settlement. Laboratory and field studies have dealt with the interaction of zooplankton with suspended sediment. Marine zooplankton ingest suspended sediment at a rate dependent on sediment concentration and mineralogy. Ingested mineral particles undergo chemical and mineral transformations which are functions of mineralogy, cation exchange capacity and residence time in the digestive tract. Zooplankton fecal pellets have a much larger settling velocity than their component particles. This increased settling rate allows clay to be deposited where the hydrodynamic nature of the environment would only allow coarse silt to fine sand deposition. Glacial flour (feldspar, quartz, trioctahedral mica, chlorite, amphibole, tourmaline, and vermiculite) enters the surface-layer of the Howe Sound fjord as a sediment plume which moves quickly down inlet while slowly mixing with the marine water. Although flocculation occurs in the lower brackish water of the surface-layer, mixing and diffusion are the dominant means for sediment to enter the lower-marine-water. Once in the lower-marine-water, zooplankton pelletization and biologic agglomeration of inorganic floccules takes place. These processes that enhance the individual particle settlement, generate a fast response time between the surface-layer and the lower-marine-layer in terms of sedimentation of particulate matter. Settling velocities of particles less than 1 μm have been enhanced over 1400 times. Size distributions of sediment deposited on the sea-bed are a function of variable multimodal and/or non log-normal size distributions from sub-laminae falling through the water column. The increase in deviation away from log-normality down inlet, for size distributions of both suspended and deposited sediment, is an artifact of the size analytical method. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Thesis (Civ.E)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1981 / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 107-108. / by Robert William Day. / Civ.E

A Dissertation submitted to the Faculty of science, University of the Witwatersrand, Johannesburg, for the Degree of Doctor of Philosophy / The Late Proterozoic Damara Oroqen (750-450 Ma} in Namibia forms part of the Pan-African mobile belt system which dissects southern Africa. The Khomas Trough in the inland branch of the orogen comprises thick multiply deformed metagraywackes and pelites of the Kuisab Formation. (Abbreviation abstract). / Andrew Chakane 2019

A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. Johannesburg, 2015. / The Palaeoproterozoic Baoulé-Mossi domain of the West African Craton in northeastern Burkina Faso hosts numerous gold deposits such as Essakane and Tarpako. Integrated strato-tectonic, geophysical, geochemical, geochronological, regional stratigraphic framework and metallogenic studies of the Oudalan-Gorouol volcano-sedimentary Belt and the Gorom-Gorom Granitoid Terrane have provided new insight into the geotectonic evolution of the northeastern part of Burkina Faso. This work outlines the structural context and architecture necessary for forming these deposits. In this work, a new strato-tectonic model is proposed for the area by integrating field data and geophysical, geochemical, and geochronological data. The integrated data highlights and characterizes the setting of the Essakane gold mine and gold camp relative to the location of other regional gold deposits, metamorphosed Birimian Supergroup, intrusive rocks and shear zones. Structural, geochemical and geochronological analyses have helped to clarify the geological evolution of the Oudalan-Gorouol volcano-sedimentary Belt and the Gorom-Gorom Granitoid Terrane during the Tangaean (D1) and Eburnean (D2) orogenies through to the Wabo Tampelse Event (D3). Further to these, zircon U-Pb geochronology data have demonstrated that the Oudalan-Gorouol volcano-sedimentary Belt and the Gorom-Gorom Granitoid Terrane represent some of the oldest outcropping geology in the Palaeoproterozoic Baoulé-Mossi domain recognised to date. The geochronology and geology suggest that the basement or a pre- Birimian crust to the Birimian Supergroup may be found in the northeast of Burkina Faso. The Eburnean Orogeny in northeastern Burkina Faso is preceded by two phases of deformation (D1-x and D1), and two phases of magmatism. The first, D1-x, is associated with the emplacement of the Dori Batholith at the onset of D1 (2164 – 2141 Ma). D1 ductile-brittle deformation formed F1 folds and discrete high-strain mylonite zones that deformed the Oudalan- Gorouol volcano-sedimentary Belt and the Gorom-Gorom Granitoid Terrane during a southwestdirected palaeo-principal compressive stress. The pre-Birimian to Birimian supracrustal rocks and intrusions were regionally metamorphosed during D1 to greenschist to amphibolite facies with development of mineral assemblage of quartz-chlorite-muscovite ± chloritoid to biotite-potash feldspar ± hornblende. D1 is also associated with volcanic arc type calc-alkaline magmatism, producing TTGs enriched in heavy rare earth elements. The Eburnean Orogeny (2130 – 1980 Ma) is characterised by northwest-southeast shortening; it was followed by north-northwest - south-southeast shortening with development of northeast trending sinistral strike-slip faults and shears. D2 brittle-(ductile) deformation is manifested by refolding of F1 by northeast-trending F2, and development of a pervasive northeast-trending S2 to S2-C foliation. Metamorphic grade attained greenschist facies during D2, with development of mineral assemblage of quartz-chlorite-muscovite ± actinolite. The Wabo Tampelse (D3) deformation event is brittle in character and does not significantly affect the regional geological architecture in the study area.

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Sedimentological analyses, including detailed facies characterization and lateral profiling, demonstrate deposition in a bedload-dominated fluvial system for the quartzose sandstones of Lee Formation. Internal (architectural) elements of the sandstones consist primarily of truncated channel-fIll sequences. Individual channel elements, up to 20 meters thick, contain a complex hierarchy of bedform deposits. The principal internal component of channels were downstream-accreting (mid-channel?) macroforms; channel elements frequently contain deposits of more than one macroform. Reconstruction of the macroforms reveals accretion primarily by superposed bedforms that migrated down a low-angle front. Steeper, giant foresets, transitional along flow with the low-angle facies, indicate that the macroform episodically developed a steep slipface. Uppermost channels within the Rockcastle Member contain macroform elements with components of lateral accretion, interpreted as deposits of alternate bank-attached macroforms. Also recognized within channel-fill deposits are minor-channel, sandy-bedform, gravity-flow (attributed to bank slumping), and channel-bottom elements. The latter element is contained within a facies sequence that suggests rising- to flood- to waning-stage deposition. In general, deposition was probably during relatively high stage; little evidence of low-stage flow was recognized. Subordinate fine-grained facies are interpreted as levee and overbank deposits. Strongly unimodal paleocurrents, lack of facies that suggest low-stage reworking and paucity of lateral-accretion features indicate deposition in a single-channel, low-sinuousity, system (i.e., a low braiding index). Fluvial architecture similar to that found in the Lee Formation has been previously explained by deposition in multi-channel, braided-river systems. However, the internal architecture of sandstone members is also consistent with a single-channel origin. Individual channels were temporarily confined, during which time the passage of several macroforms aggraded the channel. Position of the channel in the alluvial plain was largely controlled by avulsion of the river from fully aggraded channel belts to other areas of the plain. Calculations reveal that avulsion of a single-channel system across a wide alluvial plain is a plausible mechanism for building the sheet-like sandstone bodies of the Lee Formation. Spatial arrangement of individual sandstone members of the Lee Formation was probably controlled by tectonic processes. Episodic thrust-loading in the orogenic belt to the east and subsequent flexure of the crust in the foreland basin caused a step-wise progression of the river system towards the west. Petrographic, sedimentologic and stratigraphic data indicate that source area and climate functioned as the primary controls on the mature composition of sandstones in the Lee Formation. Source areas were composed primarily of quartz-rich sedimentary rocks and were located chiefly to the northeast/north. A east/southeast source area supplied subordinate and low-grade metamorphic rock fragments. Intense weathering, associated with humid tropical climates, acted upon the detritus throughout the sedimentation cycle. Less important controls on composition were tectonics and transport/depositional processes that extended exposure of the sediments to the severe climatic conditions. Quartzose sandstones of the Lee Formation reflect lower rates of tectonic subsidence and greater recycling of sand-sized grains during transportation and temporary deposition on the alluvial plain, relative to lithic time equivalents to the east. / Ph. D.