This thesis uses a combination of two-dimensional (2D) and three-dimensional (3D) seismicreflection data to investigate the morphology and internal architecture of mass transport deposits (MTDs) from the west Nile delta, offshore Egypt and from the Deepwater Taranaki Basin, New Zealand. The overall aim of the project is to gain an improved understanding of the impact of MTDs on hydrocarbon seals. To this end a novel seismic based classification for MTDs that is directly mappable onto the problem of defining their potential as sealing sequences is proposed based on results of investigations from three core research chapters. In the first core chapter, the phases and mechanisms of failure of three main MTDs (termed A, B and C) in the western Nile delta (Eastern Mediterranean) was investigated using 3D seismic data. Analysis of the geometries of the MTDs suggests that they were emplaced in at least two main phases: Progressive failure occurred initially with MTD A cutting through MTDs B and C. Retrogressive failure then occurred due to the natural unbalance of the supposed headwall of MTD A. Reconstruction of the pre-seabed topography suggests a minimum total volume (residual and depleted) of remobilisation of the order of 750 km3, making this amongst the largest submarine landslide complexes documented to date. It is suggested that this giant slope failure might have posed a risk to the integrity of petroleum seals considering that the failure occurred in a gas rich province of the western Nile delta. In the second core chapter, six large scale MTDs, stacked and locally amalgamated making up c. 50% of the stratigraphic succession were recognised and mapped using 2D seismic data. Key kinematic features suggest a north-westerly transport direction for all of the MTDs with the exception of MTD 6, having a south-westerly transport direction. There is seismic stratigraphic evidence in the form of both lateral and basal truncations suggesting that the MTDs were erosive during their emplacement. Estimation shows that c 70% of the final volume of MTD 6 was contributed from substrate cannibalization greater than the other five MTDs in the study area. This work suggests that the rheology of the substrate immediately beneath the seafloor might not be the only factor controlling the degree of substrate cannibalisation during MTD emplacement and that the nature of any triggering mechanism might also play an important role. This has a bearing on the MTD content (sandy or muddy dominated MTD) and would in turn influence the seal integrity of MTD. The final core chapter presents insights into the dynamics of emplacement of MTD 6 using 3D seismic data. MTD 6 consists of five distinctive domains (labelled A – E). Domains A – C show evidence of deformation and remobilisation of c. 30% of a lower transparent interval while Domain D is characterised by a partial or complete loss of seismic character coupled with c. 30% reduction in thickness compared to adjacent domains. Based on the deformation styles, the transition across domain boundaries and the observed volume loss, a progressive stratal disaggregation is inextricably linked with gravity spreading as the mode of emplacement of MTD 6. This study highlights the power of 3D seismic data in unravelling the detailed processes involved during MTD emplacement and which may have significant implications as regards the translation and emplacement of other submarine slope failures in other continental margins.

During the Miocene (23.03 to 5.33 Ma), western Amazonia experienced major changes in its geography and biodiversity as a response to Andean uplift. To better understand these changes, the palynology of the Solimões Formation (NW Brazil) is presented with the objective of providing age control, and establishing palaeoenvironments and pollen richness within the framework of geological and climatic events. The ninety-five palynological samples yield 491 palynomorphs, of which 76 pollen and 25 spores are new. Correlation with a nearby calibrated biozonation resulted in ages from 18.7 to 10.7 Ma (late early to earliest-late Miocene). The pollen associations are typical of Amazonian humid forests, with abundant palms, Bombacoideae, trees and grasses, and lack diverse and abundant herbs or dry forest indicators. Spikes in algae and dinoflagellates show phases of lake development and two marine incursions – one between 18.4 and 17.8 Ma, and another between 14.1 and 13.7 Ma. Statistical analyses of the data show inundations had no effect in the vegetation composition. Estimates of diversity using different metrics clearly show a diversity increase and community change at ca. 16 Ma, independent of lithofacies. This change is driven by the Middle Miocene Climatic Optimum and not correlated with any of the marine incursions. Altogether, the results bring more detail to the environmental history of western Amazonia, establishing two inundation events and furthering the climate diversification relationship in Neotropical biomes into the Miocene period.

This thesis investigates torrent erosion in Lake District mountain catchments, Northern England. A nested research approach was used. Detailed investigations were undertaken at two case study sites (Iron Crag, Raise Beck) together with a survey of torrents across the Skiddaw and Helvellyn massifs. At Iron Crag an annual sediment budget was constructed by monitoring hillslope, channel and fan processes. Particle size characteristics of sediments, and the history of fan development were investigated. Results show channel and bank sediments are the main source of material supplied to the fan. Large rainfall events cause significant change in the channel, banks and fan. The impact of different meteorological conditions on sediment characteristics is complex, however a seasonal cycle of sediment production (winter) and exhaustion (autumn) exists. Historically, initial fan aggradation predates 36 BC, but a rapid phase of deposition began between 1200-1400 AD. Investigations at Raise Beck focussed on a flood that occurred in January 1995 and caused channel avulsion and shallow landsliding. This was reconstructed using a range of geomorphological and sedimentological evidence. Palaeohydrological methods give a discharge between 27- 74 in s-1. whereas as rainfall-runoff values range between 4-6 m3 s-1. The magnitude of the 1995 flood was smaller than two 19th Century events, but would still exceed the capacity of contemporary engineered channels. The regional survey considered the characteristics and importance of torrents,mountain streams, and debris flows; and provided a context for work at the case study sites. The case study sites are distinct members of the regional populations. Raise Beck being the largest (133 ha) and highest (858 m O. D. ); Iron Crag amongst the smallest (2.4 ha) and lowest (600 m O. D. ). Overall, torrents and hillslope debris flows are minor components of the landscape (aerially 2.1 % Helvellyn massif, 0.4 % Skiddaw massif). Sites are preferentially located in regard to altitude and slope. Debris flows are related to geological type. Large torrent floods are relatively rare and can be broadly related to regional flood episodes. Contemporary debris flow activity is of low magnitude and frequency.

The British-Irish Ice Sheet (BIIS) is predicted to have deglaciated rapidly from ~ 18 ka, in response to rising sea level and temperature, similar forcings experienced by modern polar ice sheets. As the main conduits of ice mass loss, the reaction of ice streams to these forcings is thought to have been central in determining the mode and timing of this deglaciation. However, lack of understanding of ice stream influence on the glaciology and deglaciation of ice sheets limits confidence in ice sheet model predictions. NW Scotland is an area of the last BIIS predicted to have been dominated by ice stream onset conditions. This thesis presents results from a geomorphological and terrestrial cosmogenic nuclide (TCN) analysis study which resulted in the production of a composite ice-sheet thermal regime map and retreat chronology for the last BIIS in this region. Mapping and surface exposure dating suggest that the regional glaciology and landscape evolution was dominated by the presence of ice-stream onset zones during Greenland Stadial-2 (GS-2). Mountain top erratics were uplifted and transported to high elevation during GS-2, before 16.5 ka BP. By inference, mountain summits were covered by ice during maximal ice sheet conditions. The existence of sharp thermo-mechanical contrasts, developed in response to ice streaming, are proposed as the main controls on bedrock erosion and terrestrial sediment deposition. The interpretation of ‘trimlines’ in NW Scotland as englacial thermo-mechanical boundaries, is verified by the identification of ‘rip-offs’, a newly recognised geomorphic feature in the UK, and by quantitative demonstration of the increase in glacial erosion in the vicinity of these boundaries. Geomorphic and TCN data supports a conceptual model of thermal inversion following ice-stream cessation. The first description of ‘till tails’ in the UK provides insight into the glaciological organisation and thermal evolution of the BIIS. A dated (17.6 ka BP) terrestrial glacial limit on the north Sutherland coast indicates early ice retreat from the shelf and provides a minimum ii constraint on ice-stream cessation. This indicates rapid loss of ice extent and volume following shutdown of the Minch palaeo-ice stream. Major ice sheet reorganisation c. 15-16 ka BP is suggested by the correlation of some lateral margin ages with high elevation erratic deposition ages implying significant ice thinning and margin retreat prior to this time. Additionally, thinning of ~300 m is predicted for some areas prior to 14 ka BP.

The recent spate of floods in many parts of Britain has stimulated substantial interest among scientists, policy makers and the public concerning contemporary trends in flood frequency and magnitude, in particular questioning whether these events exceed historical extremes. However, detecting a clear signal of recent intensification in the flood regime is hampered by the relatively short timescales covered by meteorological and river flow data. Lake sediment sequences have proven a valuable archive of historical flooding over centennial and millennial timescales elsewhere in Europe and globally, but this thesis presents one of the first attempts to extract flood histories from the sediments of lakes in Britain. It adapts a detailed field and lab-based approach to test the hypothesis that discrete layers can be distinguished from long sediment cores (1 – 3.5 m) that were probably deposited by high-magnitude floods based on their particle size and geochemical signatures. The programme of research was developed and applied at Brotherswater (River Eden catchment), northwest England, and then further tested at the Loch of the Lowes (River Tweed catchment), southern Scotland. A detailed literature review led to the creation of a conceptual model to guide field site selection, based on the catchment-lake configuration and hydrological regime of individual sites. Characteristics deemed critical include a high catchment:lake area ratio to maximise sediment availability, limited pre-lake sediment storage and an effective sediment conveyor, as well as simple lake bathymetry. The viability of µXRF scanning to characterise flood laminations within wet sediment cores was assessed in detail. A new method of calibrating geochemical concentrations where the water content varies substantially (50%) down-core based on x-ray scattering is described, and the first inter-comparison between different core scanners is performed. The analytical resolution of the ITRAX can reveal laminations too thin to manually sub-sample but the dataset can be noiser, especially after correction to the dry-mass basis. Caution should be used when interpreting ITRAX data at the sub -mm scale to ensure peaks and troughs represent real changes in sediment composition. Inspection of multiple sediment cores extracted along a delta-proximal to distal transect in Brotherswater, coupled with high-resolution (0.5 cm) particle size measurements revealed silt-dominated (90th percentile grain size (P90) ~ 16 µm) sediment matrices frequently punctuated by coarser-grained sand layers (P90 >100 µm) that are lighter in colour. These layers cannot be easily characterised geochemically, most likely due to the volcanic bedrock in the catchment, but constitute the stratigraphical signature diagnostic of repeated high-magnitude floods for the River Eden catchment. Sediment supply varied substantially through the late-Holocene at Brotherswater, complicating the particle size record. A normalisation approach was tested to remove the background trend and identify notable particle size peaks (>1 standard deviation from the longer-term moving window) and the similar profiles produced for three cores from Brotherswater suggests the technique has been able to produce a record of major floods in the Patterdale Valley spanning the last 1500 years. Geochemical profiles at Brotherswater are dominated by enhanced metal deposition during the last 300 years, especially Pb, which mimics and could be used as a surrogate for production data for the nearby Hartsop Hall Lead Mine. The down-core pattern of Pb deposition is strongly reproducible in twelve cores extracted from different parts of the lake and reveals reveals the pattern, rate and controls over sediment deposition, with post-1860 accumulation rates four times greater near the inflow. A coherent chronology that integrates short-lived radionuclide dating (137Cs, 241Am, 210Pb), 14C ages and the geochemical contaminant markers for Brotherswater reveals that the last millennium was characterised by flood-rich and flood-poor phases generally 50 – 100 years in duration. The timing of these phases is significantly correlated with annual precipitation reconstructions, indicating a link between rainfall and flood generation. Some temporal correspondence between flood occurrence and phases of the North Atlantic Oscillation is observed but the relationship frequently breaks down. At Brotherswater, flood deposits have been most frequent during the 20th Century but isolating the influence of human activity on the sediment record is challenging. Sixteen months of process monitoring at Brotherswater using sediment traps confirms the mechanics of sediment delivery and shows a strong continuity of current process to the late-Holocene sediment record. Particle size signatures were identified for a major winter flood, low-flow conditions and the regular flushing of the sediment system by successive low magnitude flood flows. Scaling the sediment trap data to an equivalent annual accumulation show how event delivery of coarse material may be masked by more regular fine-grained sedimentation through the year. The revealed anatomy of the annual sediment accumulation cycle has significant implications for palaeoflood research with process understanding at each site clearly a critical precursor to any sediment-based flood investigation. Laminations interpreted as palaeoflood deposits in the Loch of the Lowes sequence also exhibit prominent peaks in particle size but differ in colour and geochemical composition from Brotherswater, which highlights the importance of developing site-specific protocols for interpreting the sediment record. The coarse bands are much darker in colour and the Zr/Rb ratio appears to be an effective proxy of particle size in this case, with higher values reflecting coarser material. Preliminary chronological information suggest a finely-resolved palaeoflood record has been recovered extending approximately 350 years at the delta-proximal zone and perhaps twice as long in the central basin. The thesis demonstrates that particle size data, supported by appropriately calibrated geochemical analyses, can generate high-resolution flood stratigraphies from upland UK lakes and these span millennia, extending our understanding of regional flood frequency.

When stones are incorporated into buildings their mineralogical composition and texture alters to adapt to the new environmental conditions. One of the most common building stones in Scotland is sandstone. Due to its high porosity and mineralogical composition sandstones can be prone to weathering. Scotland's diverse stone built heritage is endangered by frequent changes in environmental conditions such as cyclic wetting and drying and temperature changes caused by insolation. Buildings also face increased pressure through climate change. In Scotland, the decay of sandstone is a serious problem that urgently requires new approaches to preserve built heritage and to reduce maintenance costs. It is therefore important to understand the extent and timescales of weathering processes. New approaches to assess stone decay are required for deciding on the best conservation strategy for historic buildings. These approaches or tools need to be minimally or non-invasive, portable and provide a consistent method to gain empirical data for evaluation of the progress of weathering. This project aims to develop two new in-situ techniques that can assess the state of decay of building stones beneath their outer surface. The developed techniques use a laser interferometer to measure dilation over time and an ultrasonic drilling tool to estimate the structural properties of the stones. These measurements are joint with micro-climate monitoring of sandstones to enable a combined assessment of stone decay. The laser interferometer can measure decay induced contraction or expansion of stones on the nanometre scale. Salt crystallisation in porous systems can be examined with very high precision under any temperature and humidity condition that enable salt growth. Characterising dilation events through precise measurement of displacement and its frequency can provide insight on the intensity of decay of the building material. The drying behaviour of different samples (unweathered, weathered and artificially weathered) was monitored to enable the differentiation of rock type and state of decay. The ultrasonic drilling tool allows identification of changes in the structure of a sample while drilling a hole up to 4 cm depth. By continuously measuring the power required to drill, porosity changes and/or the presence of salt at depth can be mapped. The use of ultrasonic tools enables penetration of the rock with less average force on the stone and a faster progress rate into hard materials without a significant wear effect on the drill bits. Operational settings can be kept constant for different physical properties of the rocks such as compressive strength. Monitoring of the power consumption enables to determine different stone types and the location of salt accumulation/damage in artificially weathered sandstones. Micro-climate monitoring includes the measurement of temperature and humidity changes at the surface of building stones. The analysis enables an identification of areas that suffer from increased stress caused by frequent and high rates of changes in temperature and humidity. A study at four historic buildings was conducted for nearly two years. The sites include the University of Glasgow, Dunkeld Cathedral, Jedburgh Abbey and Fort Charlotte (Shetland Islands). Seasonal changes, stone type and north-south elongation were evaluated for determining rocks with increased weathering risks. The developed techniques provide a more precise identification of stone weathering and allow for better prediction of the decay processes. The techniques allow up-scaling from the lab to the field, and can potentially be used in-situ on historical buildings under site conditions.