Due to the potentially wide-reaching impacts on climate and sea-level change of a declining Greenland Ice Sheet (GrIS), the mass balance of the past decade has caused concern that the ice sheet is reacting to increased temperatures of the industrial era and that the ice sheet is in the initial stages of deglaciation. Global mean sea-level has been rising at a rate of 1.8 +/- 0.5 mm/yr over the past 50 years (Bindoff et al. 2007), and this has accelerated to 3.1 +/-0.1mm/yr (Cazenave et al., 2008) over the past decade. This study shows that although the surface mass balance of the GrIS can react quickly to changes in temperature, overall the ice sheet is in near balance over the period 1866-2005. During 1866-2005, the contribution from the GrIS to eustatic sea-level change is not larger than the error attached to current estimates of global mean sea-level rise. A novel type of relative sea-level data gathered from salt marshes in the south west of Greenland cover the period from ~1200 to 1800AD and show that a major slowdown in local sea-level rise from ~3mm/yr to ~0mm/yr occurred around 1500-1600 AD, with no significant departure from a 0mm/yr trend thereafter. Large contributions to sea-level change from steric changes and cryospheric sources outside of Greenland are ruled out as major drivers of this deceleration in sea-level fall. Modelling results indicate that the slowdown in relative sea-level is most likely due to the combined contribution of dynamic-related ice loss from Jakobshavn Isbrae and a delayed earth response to mass loss during a period of elevated temperatures from ~1000-1500AD. When considering the saltmarsh sea-level data for the 20th century within the context of the complete time series, the magnitude of ice loss in west Greenland for the past decade does not appear to be anomalous. This analysis suggests that similar mass loss has been sustained for several centuries prior to 1500AD.

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The Niger Delta fold and thrust belt occurs in an area of tectonic shortening – caused by the thin-skinned gravitational collapse of large deltaic sediment wedges above a ductile overpressured shale. Syn-sedimentary processes such as down-slope flowing gravity currents interact with the deforming seafloor topography to produce growth packages that record the deformation history of the folds. The thesis documents the spatial and temporal interaction between Pleistocene to Recent submarine channels, and folds/thrusts that have been growing since 12.8 million years ago (Ma). 3D seismic reflection data and key stratigraphic/horizon ages are used to constrain and analyse the spatial and temporal variation in shortening of major folds having seabed relief. Geomorphic techniques were applied to quantify the geomorphic responses of submarine channels developing coevally with structural deformation. This thesis documents two types of structures (fault-propagation folds and a detachment fold) whose cumulative strain (shortening) varies spatially and through time. The maximum interval shortening rate occurred between 9.5 Ma and 3.7 Ma, and has reduced significantly from that time to present. Channels show a range of interactions with structures, from simple deflection to fold tips to complete diversion. However, channels are capable of crossing the actively growing fault-propagation folds in positions of recent strain minima and at interval strain rates that are generally less than 15 m/Myr. In contrast, channels have been completely diverted by the broad detachment fold albeit growing at comparably lower rates. This thesis emphasizes that careful fold displacement – distance measurements which bracket the time interval of channel system development are very important for predicting sediment pathways in deepwater settings. Detailed geomorphic analysis showed that the bathymetry longitudinal profiles of the active channels are relatively linear with concavity values that range from -0.08 to ̵ 0.34, with an average profile gradient between 0.9[degrees] and 1[degrees]. In contrast, channel systems that have been abandoned and buried for long period of time, have longitudinal profiles that are more convex. The profiles of both the active and buried channels are characterized by knickzones that are apparent near mapped structures – and implicitly record variations in substrate uplift rate. The recently active channels (the modern thalweg) show no systematic width change down-system but they do show an increase in incision depth/erosion of up to 70 % at structural locations. However, the channel system (made of several cut-and-fill sequences), shows clear width narrowing together with time-integrated incision and erosion in response to time-integrated structural uplift. Estimates of the down-system variation in channel bed-shear stress and flow velocity, using the thalweg-geometry of the active channels, suggests that near growing folds and thrusts, the enhanced bed-shear stress-driven incision is up to 200 Pa. and the flow velocity is up to 5 m s-1. In essence, the linear nature of the active channel profiles, in comparison to the convex nature of the buried channel profiles, suggests that the active channels are able to keep pace with the time-integrated uplift of folds and thrusts, and therefore appear to be in topographic steady-state with respect to structural uplift since at least 1.7 Ma. Facies analysis using the seismic data showed that the main seismic facies include: (i) channel axes sands and top-channel sands (ii) sheet-sands or crevasse splays (iii) slump deposits and (iv) pelagic drapes. The growth of structures with seabed relief has affected the location of channel avulsion, the locus and the deposition/distribution of sheet-sands (splays). These splays can spill over the growing fault-propagation folds in areas of lower fold growth rates, and absence of seabed scarps; but are completely blocked, and subsequently incorporated onto the limb of a broad detachment fold in the east of the study area as incoming channels are forced to divert through time. This thesis has contributed to the understanding of: (1) Deformation by thrust-related folds that have been growing since ca. 12 Ma, and attained maximum interval growth rates between 9.5 Ma and 3.7 Ma. These maximum growth rates have reduced significantly in the last 3.7 million years during which submarine channels that are generally less than 1.3 million years old also occurred. (2) How modern seabed channels (i.e., recently active channels) have responded to the time-integrated growth of structures along their paths; and the related effect on the positioning of channels pathways, which in-turn, governs the depositional system – especially the distribution of sands in the toe-thrust area of the deepwater Niger Delta. (3) The time-integrated channel system erosivity, the evolution of the channel system geometry and the channel system fill as these systems interact with active structures through time. (4) How submarine channels in the deepwater Niger Delta achieve, and maintain bathymetric steady-state over periods of approximately 1 – 1.3 million years.

The Rockall Trough is one of the largest of the relatively unexplored basins that form the northeast Atlantic Passive Margin, and many aspects regarding its evolution remain unresolved. The basin can be subdivided into two distinct sub-basins termed the Northern and Southern Rockall Trough. The main period rifting occurred during the Cretaceous Period, with multiple rift events that culminated with the initiation of seafloor spreading in the North Atlantic Ocean. There are significant departures in the basin's subsidence-uplift history from classical post-rift thermal subsidence models} particularly during the Cenozoic evolution of the Rockall Trough. These include regional Paleogene uplift} associated with the development of the Iceland Plume} and a late Eocene deepening event. Possible explanations for the deepening event include compressional related buckling of the lithosphere or the loss of thermal support associated with the Iceland Plume. This study applies numerical} lithosphere-scale models to the Rockall Trough in order to gain insights into the mechanisms responsible for the early-evolution of the basin and the subsequent post-rift events. These models are used to test different hypotheses regarding the timing and nature of both extensional and compressional events} as well as the influence of thermal anomalies. The mechanisms that control the early evolution of the Rockall Trough have been modelled and include both uniform and non-uniform lithosphere extension combined with single- and multiple-rift scenarios. The formation of lower crustaI bodies, both magmatic underplating, mantle serpentinisation, and lithosphere rheology have been modelled in order to access the relative importance of all factors controlling the evolution of the Rockall Trough. In addition} the difference between the southern and northern Rockall Trough have been examined. The effects of the Iceland Plume have been modelled to assess its impact on basin evolution. This modelling has enabled the influence of thermal anomalies} the extrusion of large volumes of igneous material and the formation of magrnatic underplating to be investigated and quantified in terms of the uplift or subsidence generated. Model results show that compression during the Cenozoic Era can produce the rapid acceleration of subsidence observed in parts of the Rockall Trough. However, the magnitude of compressional related subsidence depends on the existing flexural deflection prior to compression. Consequently the interplay between the amount and distribution of crustaI thinning, the formation of lower crustal bodies, both magmatic underplating and mantle serpentinisation are crucial to accurately modelling the effects of compression on basin development.

This research identifies and validates a data-driven statistical method for morphological and morphodynamic modelling and prediction. The method, called the spatial regression model has been modified to account for a single forcing factor. In the model, spatial behaviour across a domain is accounted for as surface functions; changes between successive surfaces then explain the spatial and temporal evolution, which is used to calculate a prediction. In the model extension, the covariability between the time series of the morphology and forcing are assessed to derive an estimate that scales future forcing. The model is applied to idealised morphological scenarios and two study sites, which are the nearshore zone of Poole Bay, governed by wave and anthropogenic factors, and the Great Yarmouth sandbank system, governed by tidal, wave and storm conditions. The idealised scenarios results show that the model identifies morphological evolution. For scenarios with temporal periodicity, stochastic effects and noise, it generated predictions with Brier Skill Scores (BSS) of ≥0.97. Accounting for forcing improves the prediction for scenarios with complex behaviour. At the Great Yarmouth site, a BSS of 0.65 is obtained using the morphological characteristics only. In using the wind time series as a proxy for the forcing, the skill score decreases. For the Poole Bay site, a 0.64 BSS is obtained assessing the morphological characteristics only. Accounting for the wave time series as the forcing improves the score compared to that without forcing for the same time period. In assuming no change occurs across the domain, the model improves on results for the scenarios but generates larger errors at the real sites. Model sensitivity is dictated by the characteristics and complexity of the morphological behaviour and the spatial and temporal resolution of the associated time series datasets, which in turn influences the prediction accuracy. The spatial regression model can be a useful tool for morphodynamic modelling applications at large scales, where accounting for external forcing conditions can improve prediction results, given certain behaviour and data properties.

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Ocean acidification (OA) as a result of anthropogenic CO2 accumulation has major implications for the calcification of marine organisms. Assessing the calcification response of coccolithophores and planktic foraminifera to OA in particular is paramount as together they produce the majority of pelagic carbonate burial and thus impact biogeochemical cycling and oceanic CO2 uptake. In this thesis, two sediment cores from Eirik Drift and the Norwegian Sea are used to reconstruct the natural calcification response of marine plankton since the Last Glacial Maximum and compare these changes to recent anthropogenic influences over the last 200 years. Reconstructions of the bottom water dynamics and thus sedimentation at Eirik Drift infers the suitability of the core for palaeo-analysis of plankton calcification. The calcification response of three foraminiferal species and two morphotypes of the dominant polar species Neogloboquadrina pachyderma are significantly correlated throughout the Holocene suggesting similar calcification mechanisms between and within species. Although the drivers of calcification appear to vary temporally and geographically, down-core planktic foraminiferal Mg/Ca and faunal assemblage counts point towards the importance of sea surface temperature and optimal growth conditions on the calcification of N pachyderma. Unlike Globigerina bulloides, N pachyderma shows little sensitivity to CO2 changes across the last deglaciation Since the beginning of industrialisation, foraminiferal calcification fluctuates within the natural long-term trends observed over the last 22 kyrs inferring minimal anthropogenic impacts on foraminiferal calcification. Interspecies-specific responses are evident, as the test weight of G. bulloides increases since the early 1900s in response to a warming North Altantic Current, whilst Neogloboquadrina incompta shows little change over the last 200 years. Furthermore, an increase in the degree of calcification of the abundant coccolithophore Emiliania huxleyi occurs in response to accelerated 20th century climate change pointing towards increased carbonate burial in the sub-polar North Atlantic under future global change.

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