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There is increasing evidence for high magnitude dust storms in high latitude environments. Yet, Aeolian processes in these areas have been largely understudied and therefore our knowledge of these systems is limited. Understanding dust emission processes from the high latitudes regions is of increasing importance because future climate scenarios indicate a reduction in terrestrial ice masses and an expansion in glacial outwash plains which are the main dust sources in high latitude environments. Of these regions, Iceland is the most researched high latitude dust source region, however our understanding of processes which lead to dust events are still poorly understood. This thesis examines the interlinking relationship between dust source and dust particle sedimentology and the physical and meteorological drivers which promote or inhibit dust emission in Iceland. This is achieved through active aeolian monitoring at source during two monitoring periods at Markarfljot, South Iceland. These measurements are complimented using secondary data sources (e.g. meteorological and satellite data), sedimentological mapping and particle analysis and laboratory abrasion experiments. This thesis is the first high resolution multi event record of dust emissions in the high latitudes and concludes by showing that potential dust concentrations and dust particle size are driven by the interlinking relationship between wind speed, sediment texture and surface moisture. Factors that affect the potential sediment availability for dust events are more important in the high latitudes than in the subtropics in driving spatial and temporal variability in dust emission. Measurements presented in this thesis are required to verify and tune regional and global modelling attempts to quantify the potential contribution of high latitude dust in the Earth system. However, further measurements are required to fully understand seasonal changes in dust emissions, across a variety of dust source units within all high latitude dust source regions.

The farming of Atlantic salmon (Salmo salar) is challenged by parasitic infestations caused by Lepeophthreirus salmonis and Caligus elongatus. A convenient and effective way to control sea lice and treat farmed salmon is by in-feed treatments such as Slice®. A reliable, accurate and reproducible method for the determination of emamectin benzoate (EB), the active ingredient of Slice®, and its desmethylamino metabolite (DES) in sediment was developed and validated. It involved methanolic extraction, clean-up using solid-phase extraction with a strong cation exchanger, and derivatisation with trifluoroacetic acid anhydride and N-methylimidazole. Analytes were quantified following HPLC separation with fluorescence detection. The method was successfully applied to determine EB and DES in salmon flesh and skin, seawater, mussels (Mytilus edulis) and seaweed (Palmaria palmata). A laboratory study showed that EB was persistent under anaerobic conditions in two different sediments at 4 and 14 ºC. A further study also demonstrated that the growth of seaweed (P. palmata) was not affected by the presence of EB and that EB did not accumulate significantly in the seaweed. This result is encouraging in view of proposed polyculture systems involving seaweeds. Studies conducted on a working Scottish salmon farm investigated the fate of EB and DES in target and non-target matrices. For three months post-treatment, EB was detected, by mass in descending order, in the salmon flesh, skin, faeces, then mucus and sea lice with concentrations in each matrix declining steadily over the period. As EB had never been quantified in sea lice before, it was unclear whether they were a significant sink for EB in the environment, following their exposure to the medicine and dislodging from salmon after feeding. However, due to the low concentrations of EB detected in the sea lice, faeces are most probably the main route for emamectin entering the environment. Sediment collected directly below and around two active walkways, over five or six months following treatment, showed that the spatial dispersion of EB and DES was mainly limited to the area within 25 m of the cage edge, although concentrations depended on sampling location in relation to water currents. Maximum EB concentrations were recorded three months after treatment. Seven days after treatment, 6 % of the total EB input was present in the sediments within 25 m of the cage edge. Neither EB nor DES were detected in seawater, mussels, periwinkles, dogwhelks and seaweed samples collected from the walkway and the surrounding environment. This work, one of the few studies of the uptake of EB by indigenous fauna and flora of an active salmon farm, suggests that it is not significantly accumulated in matrices outwith the target organism and the sediment.

Marine sediments play an important role in the global carbon cycle, where they are ultimately important for recycling of carbon. At the sediment-water interface carbon is in constant movement both into and out of the sediment. However some environments are more important for the natural storage of carbon. Over long time scales this process has a role in climate regulation. Measuring the total O2 uptake represents a good proxy for the turnover of organic material at the sediment surface in oxygenated sediments, and equally the release of O2 represents benthic primary production. Many important biological processes are regulated by the availability of O2 at the seabed including: fauna composition and activity, phosphate exchange, nitrogen cycling and burial of organic material. Understanding of the rate and efficiency at which carbon turnover is occurring in marine sediments provides a valuable insight to the regulatory role they play in climate control. Investigation of marine sediments is best done in situ where possible, and the development of benthic “landers” has allowed measurements to be conducted at the sediment-water interface. Most recently, a novel approach known as “Eddy Correlation” (EC) has been developed. It allows quantification of the O2 exchange across any surface from simultaneous measurements of vertical velocity flow and oxygen concentration within the benthic boundary layer. The large sediment area accounted for; the high measuring frequency and the non-invasive nature are theoretical advantages over traditional methods such as benthic chamber incubations and O2 microprofiles. This study has shown that it is difficult to achieve consistent and improved measurements using EC compared to traditional methods due to the complex nature of the equipment and data analysis. Data does suggest that EC can be a strong complimentary tool for benthic carbon exchange studies. This project presents the first use of this technology across a range of benthic environments, from temperate coastal sediments and maerl beds to high-Arctic sediments and sea-ice. The method has allowed accurate quantification of the benthic remineralisation rates and carbon turnover efficiency in the coastal and maerl environments, but less so for the more complex under sea ice and cold Arctic environments. Rates presented agree well with other published studies documenting the use of this state-of-the-art technology.

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The Zerrissene turbidite system of central-western Namibia is a late Proterozoic sequence which consists of dominantly siliciclastic turbidites interbedded with minor turbiditic and hemipelagic marbles. The basin in which these sediments were deposited is located at the junction of the coastal and intra-cratonic arms of the Pan-African Damara Orogen, and an understanding of the sedimentary evolution of this basin is therefore important to the understanding of the development of the orogen as a whole. One major and two minor phases of folding have deformed the sediments, but the grade of metamorphism is low and sedimentary structures are often well preserved. Further, the area lies entirely within the Namib Desert and the lack of vegetation cover results in good outcrops providing an unusual opportunity for examining a large Precambrian turbidite system. The system consists of five formations: three siliciclastic and two mixed carbonatesiliciclastic units. The floor of the system is not exposed, and the oldest sedimentary rocks which outcrop are siliciclastics of the Zebrapiits Formation. This is overlain successively by the Brandberg West Formation (dominantly calcareous), the Brak River Formation (siliciclastic), the Gemsbok River Formation (calcareous) and the Amis River Formation (siliciclastic). Nine silicilastic turbidite facies have been recognised in the basin. These are facies A₂ (disorganised onglomerates), B₁ (horizontally laminated to massive greyackes), C₂ ("classical" turbidites), Dl (sandstone-shale couplets with base cut-out Bouma sequences), D₂ (sandstone-shale couplets with less sand than shale and base cut-out Bouma sequences), E (coarse, discontinuous sandstone-shale couplets), F (slumped units), G (shale) and H (glacial dropstones). Four facies are associated with the carbonate horizons, and these carbonate facies are given the suffix c to distinguish them from similar siliciclastic facies. These are facies Ac (disorganised and graded marble breccias), facies Cc (graded carbonates), facies Gc (hemi-pelagic marbles) and facies G (pelagic shales). The basal Zebrapiits Formation is made up of relatively thin packages of thin- to thickbedded, laterally continuous facies D₁, D₂ and B₁ beds encased in thick envelopes of shale. This type of sequence is typical of a distal lobe-fringe, and requires an unconfined basin-floor on which it can develop. The overlying Brandberg West Formation consists of a basal portion of interbedded facies Cc and G, followed by a sequence dominanted by facies Gc. This sequence is interpreted as representing outer-apron carbonate turbidites, derived from multiple point sources (facies Cc), with background pelagic settling (facies G) overlain by hemi-pelagic deposits (facies Gc). A reversal back to siliciclastic turbidites followed with deposition of the Brak River Formation. This sequence comprises relatively thick packages of laterally continuous facies B₁, D₁, and D₂ beds sandwiched between facies G shales, a succession characteristic of a lobe to lobe-fringe environment with intermittent abandonment of lobes. An unconfined basin floor adjacent to a passive margin is required for the development of this type of sequence. Glacial dropstones (facies H) are found in the upper portions of this formation, and slumped beds are also present (facies F), but are uncommon. The facies F beds are only found in association with facies H and are therefore considered to be genetically related. Slumping of beds was possibly caused by an oversupply of sediment from ice-rafting which caused instability. The overlying Gemsbok River Formation has a sequence similar to the Brandberg West Formation in that the basal portion consists of interbedded facies Cc and G, which is overlain by a thick sequence of largely facies Gc beds. Minor facies Ac beds occur near the top of the overall sequence. This formation is interpreted as an outer-apron succession with the facies Ac beds representing distal inner-apron deposits, indicating progradation of the system. The youngest unit in the basin, the Amis River Formation, shows strong lateral variation from west to east. In the west the sequence comprises laterally continuous facies B₁, C₂, D₁ and D₂ with rare, discontinuous facies E beds. Facies G is relatively minor in the sequence. In the east the succession is dominated by facies D₁, D₂ and G, and this succession is interpreted as a sequence of distal turbidites which were deposited on a basin-plain. The system developed by aggradation rather than progradation as only minor cycles are developed. Geochemical and petrological features indicate that the entire siliciclastic system was derived from a granite-recycled orogen terrane. Palaeocurrent data are unreliable because of the deformation, but transport was initially from the south-west, moving later to the west and north-west. The provenance of the carbonates is uncertain as reliable palaeocurrent indicators are rare, but they could have been derived either from South America or from the extensive carbonate deposits developed on the north-western margins of the basin. The Zenissene siliciclastic turbidite system represents the distal portion of a major submarine turbidite system, the more proximal parts of which now lie west of the exposed basin, either under the Atlantic Ocean or in eastern South America. The calcareous deposits developed as an apron adjacent to a multiple point source, the position of which is at present unknown.

It has been suggested that the dominant controls on alpine sediment transfers during the Holocene Epoch relate to climate change, specifically paraglacial sedimentation and Neoglacial activity. Alpine lakes with appropriate geometry and hydraulic conditions trap a high proportion of sediments inflowing from their surrounding drainage basins. Thus alpine lake sediments have the potential to yield a comprehensive, integrated signal of drainage-basin geomorphic activity through time, which may be interpreted as a proxy record of Neoglacial activity. This study is concerned with the interpretation of alpine lake sediments in glacierized drainage basins as records of Neoglacial activity. It adopts an explicitly geomorphological approach that integrates an understanding of the drainage basin sedimentary system, specifically sediment sources and transfers, with the interpretation of lake sediment deposits and extends existing models of alpine sedimentary response down-valley, away from the immediate proglacial environment. A down-valley sequence of four valley bottom lakes, Kha, Klept, Kokwaskey and Kwoiek, within the Kwoiek Creek watershed, southeastern Coast Mountains of British Columbia, were studied. Sub-bottom sounding and multiple cores from each lake allowed identification of lake-wide changes in sediment input through time; in addition terrain mapping and characterisation of sediment sources provided a framework within which to identify the sources of the lake sediments and their fluctuations through time. Preliminary characterization of the sediments broadly separated organic and clastic components. Detailed laboratory analyses revealed organic matter content to be a good inverse indicator of sedimentation rates. Grain size analyses revealed three distinct textural populations. Graphical partitioning of the cumulative grain size distributions identified each fraction for further analysis. The provenance of the coarsest and intermediate fraction was determined through SEM surface texture analysis of a statistically representative number of grains. The coarsest fraction was derived from localized colluvial sources. The intermediate fraction was derived from glacial sources and strongly filtered downsystem. The finest fraction was characterised as glacial in origin because of consistent trends in its variability at the drainage basin scale through time. Fluctuations in the total influx of the intermediate and finest fractions are interpreted as a proxy record of Neoglacial activity in the watershed. Analysis of persistence in the sedimentation data indicates history of the order 100 yrs, which is interpreted as an index of the relaxation time of sedimentary stores. Basal dates on the sediments provide the earliest dates for deglaciation in the southern Coast Mountains, suggesting that extensive areas of southwestern British Columbia were ice free prior to 11 500 B.P. Three phases of Neoglacial activity centred 6000 to 5000 B.P., 3500 to 2900 B.P. and post 750 B.P are suggested by increased sedimentation rates for glacially-derived material. When compared with reconstructions from a pollen study conducted within the watershed and regional chronologies reported in the literature, there is remarkable consistency. The major advantage of the lake sediment approach as developed in this study is the continuity and apparent sensitivity of the derived proxy records. These records permit a consideration of both the magnitude and frequency of palaeoenvironmental change, specifically Neoglacial activity, at one site. Such a record has not been found elsewhere in British Columbia, where discontinuous terrestrial records have been used. / Arts, Faculty of / Geography, Department of / Graduate

This study investigated the process by which molybdenum was removed from sea water in Saanich Inlet, an anoxic fjord, whose basin sediments are enriched in molybdenum. Water samples were collected in the inlet from July 1971 to April 1972 at about two month intervals and were analyzed for pH, salinity, temperature, dissolved and suspended molybdenum, suspended manganese and iron, and dissolved oxygen and hydrogen sulphide. A new technique for the determination of dissolved and suspended molybdenum was developed. The data showed a negative correlation between dissolved molybdenum and suspended manganese, and a positive correlation between suspended molybdenum and suspended manganese. This suggested that molybdenum was being scavenged from sea water by suspended manganese oxides. The distribution of molybdenum in the basin surface sediments was qualitatively correlated to the distribution of suspended molybdenum in the overlying basin water. During about September to December, the molybdenum profile was described by a two layer system. In the top 75 m layer the molybdenum followed the salinity profile. Below 75 m the distribution was described by a one dimensional mathematical model. The yearly deposition of molybdenum in the basin sediments was calculated from the estimated sediment deposition rate. This value was not inconsistent with that calculated from the rate molybdenum is scavenged by manganese oxides from the basin water. / Science, Faculty of / Chemistry, Department of / Graduate

Alluvial fan construction within British Columbia was dependant upon temporary conditions resulting from deglaciation; there is no significant fan aggradation at present. Five study areas were selected from the semi-arid sections of the Fraser, Thompson, Bonaparte, South Thompson and Similkameen valleys. The Tertiary and Quaternary geo-morphic histories of these areas are similar in many respects--most significantly, one or more phases of Pleistocene glaciation were followed by fluvial and lacustrine aggradation--but vary regarding the amount of subsequent downcutting by major rivers. This ranges from several hundred feet in the Fraser and Thompson valleys to a few feet or none in the Similkameen and Bonaparte valleys. Stratigraphic evidence from the Fraser Valley indicates that fan building commenced soon after the valley floor became ice-free, probably whilst glacial conditions persisted in tributary basins. It continued during aggradation by major rivers and for sometime afterwards. In the Thompson and South Thompson valleys fans were most recently built upon degradational river terraces. The occurrence of Mazama volcanic ash within fans indicates that construction continued until after 6,600 years B.P. Fans were built during a phase of landscape readjustment from predominantly glacial to predominantly fluvial conditions. They resulted from the secondary deposition of glacial drift and locally weathered material by streams and mudflows. Fan composition was dependant upon the nature of the available material and upon the character of the parent basin. For example, the widespread occurrence of glacio-lacustrine silt in the Thompson Valley gave rise to fans composed of silty mudflow gravels. Generally, small, steep basins produced mudflows whereas larger basins had more constantly flowing streams which deposited fluvial gravels. Fan aggradation declined as the drift supply was exhausted; deposition of material derived by current weathering was insufficient to maintain the growth of the fans. After deposition ceased many fans were dissected as a result of local base-level lowering controlled by degradation of major rivers and/or fan-head trenching initiated as the debris supply declined. Fan-head trenching is best developed in the South Thompson Valley; base-level dissection predominates in the Fraser and Thompson Valleys. Where fan building persisted during degradation, multilevel fans were constructed. Statistical correlations among morphometric parameters describing fans and related basins indicate that basin characteristics exerted an influence upon fan geometry through the nature of the fan building stream. There relationships vary regionally, possibly reflecting lithologic, climatic and geomorphic contrasts. British Columbia fans are steeper and display a greater variation of morphometric relationships than fans of the arid American Southwest. Fans resulting from deglaciation are distinguished by use of the prefix "para-glacial". / Arts, Faculty of / Geography, Department of / Graduate

M.Sc. (Geology) / Please refer to full text to view abstract