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Oviraptorosaurians were a group of theropod dinosaurs that reached high diversity in the Late Cretaceous (100.5-66 million years ago). Later diverging members evolved a distinctive cranium which was extensively pneumatised, short and tall, and ended in a robust, toothless beak. Their skull has been previously interpreted as adapted for a powerful bite as part of a herbivorous or omnivorous diet. This thesis focusses on testing whether these interpretations of oviraptorosaurian cranial function are accurate. Digital 3D models were created of four key oviraptorosaurian species - early diverging oviraptorosaurian Incisivosaurus gauthieri, and later diverging oviraptorid oviraptorosaurians Citipati osmolskae, Conchoraptor gracilis, and Khaan mckennai. Finite element analysis using scaled loads demonstrates oviraptorosaurian cranial shape was stronger (lower stresses) and more efficient (lower total strain energy) compared with other herbivorous theropod crania (Erlikosaurus and Ornithomimus) and performed similarly well or better compared with large carnivore Allosaurus. Digital volumetric reconstructions of jaw adductor musculature quantify elevated bite forces in oviraptorosaurians compared with other herbivorous theropods (349-499 N in Citipati down in order of cranial size to 53-83 N in Incisivosaurus). Maximum angles of oviraptorosaurian jaw gape were estimated as similar to but more limited than reported estimates for herbivorous theropod Erlikosaurus and greatly more limited than carnivorous theropods. When approaches were combined to model muscle driven biting, oviraptorosaurians display greater cranial stress than other theropods indicating that the increased relative force of their jaw adductor musculature outweighs the effect of a comparatively strengthened cranial morphology. Oviraptorid crania may function closer to structural safety limits while feeding due to the influence of other functional or developmental pressures acting on their cranial shape. Nevertheless, it appears Oviraptoridae were adapted for powerful bites as part of a predominately but not necessarily exclusively herbivorous diet, distinct from other herbivorous theropods, while cranial function varied among oviraptorids with different species favouring different positions of biting.

The work in this thesis relates to the field of gravimetry, the measurement of gravitational fields and their variations, which is carried out using highly-sensitive accelerometers known as gravimeters. By using gravimeters to measure the changes in gravitational field strength from place to place, it is possible to detect differences in the concentration of mass around the gravimeter and this has historically been used to monitor geophysical activity (such as variations in groundwater, volcanic activity or glacial mass), for geological exploration (such as searching for mineral or hydrocarbon resources) and many other applications. This work covers a range of topics in gravimetry, starting with the use of computer programs to simulate the gravitational fields that would be generated when a submarine travelled past a stationary gravimeter, or array of gravimeters, situated underwater. This is done with the aim of estimating the efficacy of a new gravimeter known as the 'Wee-g' under development at the University of Glasgow at the time of writing and also has applications to the gravitational detection of submarines more generally. The gravitational field of a 100m-long submarine is simulated, using a simplified one-dimensional density profile approximating the real density variations along the length of a large submarine. The simulated gravity field is then compared to the sensitivity of a prototype Wee-g gravimeter of 5µGal/ √ Hz to give an initial estimate of the maximum detection range of such a signal by the Wee-g, which is found to be approximately 20m. Then, synthetic noisy signals are made by combining the simulated gravity signals with real Wee-g sensor noise data and digital signal processing methods are used to try and recover the corrupted signal from the noise in a way that maximises the detection range. Matched filtering is applied which uses foreknowledge of the signal being searched for to significantly increase the signal to noise ratio (SNR) in the noisy data by an order of magnitude, which increases the Wee-g's detection range of the modelled submarine to ∼ 30m. In addition, computer programs are made that determine a quantity known as the terrain correction at a given gravity survey point using digitised elevation data describing the surrounding topography. Terrain correction is the effect that the presence of surrounding hills and valleys has on the gravitational field strength at a location and, if it is not accounted for, substantial variations in gravity (and hence, potentially useful information) can be partially or completely obscured. Methods already exist to calculate the terrain correction but these are either slow and laborious, inaccurate (in comparison to contemporary gravimeter performance) or both, while the program presented in this work makes use of modern computing speed and high-accuracy elevation maps to improve on these. The terrain correction program presented here analyses terrain out to a distance of 166.735km from the survey point, using 1m-resolution LiDAR elevation data to describe the nearest 2km2 , and can calculate terrain correction values in approximately 9s when run on a computer with 8GB of RAM. Terrain at all distances from the survey point is modelled using many flat-topped rectangular prisms and the gravitational field strength due to each prism is calculated using an already existing analytic solution. An in-depth analysis of the terrain correction computation of the innermost 2km is carried out to compare the accuracy of the method used with simple analytic solutions. This analysis concludes that terrain corrections can be calculated with an uncertainty of 2µGal or less when using 1m2 -resolution elevation data, provided the terrain immediately around the survey point has an incline of less than 10◦ . Finally, two gravity surveys carried out in January of 2020 by the author with a Scintrex CG-5 commercial gravimeter are described: one in the Campsie Fells - a range of hills roughly 10km north of Glasgow - and the second in the cloisters of the Gilbert-Scott building on the University of Glasgow campus. The Campsies survey is compared with a gravimeter survey of the same region carried out in 1969 and discrepancies of up to a few mGal are observed, understood to be due to terrain correction inaccuracies in the older survey. Results from the survey in the cloisters are compared to the gravitational field due to underfloor air ducts described by plans of the building but little correlation is found. This is suspected to be the result of either inaccuracies in the building plans or the impact of environmental noise on the measurements.

The Northern Cape Province of South Africa is host to some of the largest deposits of iron and manganese metal in the world, contained in two separate districts, namely the Kalahari (KMF) and Postmasburg Manganese fields (PMF). The current thesis attempts to shed light on the chronicle of the complex epigenetic history of the two ore fields by focusing on the previously underexamined recurring theme of gangue alkali-rich assemblages, contained in and flanking a series of Fe and Mn orebodies. The principal outcomes of this study not only (a) set constrains on the characteristics, origin, sources, timing and relationship of alkali mineralization between the KMF and PMF, but also (b) challenge current ore genetic models by exploring the role of regional "alkali flooding" as a shared mechanism in the formation or at least hydrothermal upgrade of the deposits, (c) are beneficial for future exploration for new orebodies in the study and other prospective areas and (d) improve our knowledge of fluid circulation in sedimentary basins.

The Early Cretaceous witnessed a progressive rise in global sea level (following the marked global low stand at the end of the Jurassic). Global temperature also rose, and species richness increased for some calcifying marine organisms - gastropods, bivalves, ostracods, calcareous nannoplankton, and foraminifera among them. This project investigates Early Cretaceous foraminiferal assemblages from a range of depositional settings and palaeodepths in the North Sea Basin and the surrounding region to study the impact of global and local environmental changes on foraminifera communities from both shallow and deep-water. This study will aim at understanding key ecological shifts that ultimately provided the opportunity for diversification within the foraminifera. The fossil material studied was obtained from the following sites: 1. Filey Bay outcrop section, and 2. North Fordon G1 borehole from the Cleveland Basin in Yorkshire, which represent the shelfal environment. 3. 16/26-B3, and 4. 15/30-7 ST2 boreholes from the Britannia Field in the Witch Ground Graben. 5. North Jens-1 borehole from the Danish Central Graben. The last three sites represent the upper bathyal environment. The results of this project provided information regarding three initial hypotheses involving increasing species richness and ecological niches expansion for planktic, benthic calcareous and agglutinated foraminifera as each of these foraminiferal groups was found to increase in species richness and abundance in specific stages of the Lower Cretaceous. However, for agglutinated foraminifera, their initial hypothesis could not be confirmed entirely because the palaeodepths of the upper bathyal environment were not significant enough to develop a proper deep-water agglutinated foraminiferal assemblage.

Chondrichthyans, the cartilaginous fishes, are a highly successful clade of vertebrates that have occupied the aquatic realm for over 450 million years. Of these, the Palaeozoic represents a key time interval in terms of their origin and early diversification, yet much of their early macroevolutionary patterns remains unresolved because of the limitations of their fossil record. Their early fossil record is poor because their mostly cartilaginous skeletons are rarely well preserved and this, in turn, has restricted the data available for estimates of their evolutionary history. In this thesis, multiple statistical methods for quantifying the skeletal completeness and estimating diversity trends are combined to critically assess the quality of the Palaeozoic chondrichthyan fossil record. A novel metric is presented to quantify levels of soft tissue preservation next to skeletal completeness in the stem-chondrichthyan acanthodians which are known to preserve notoriously little skeletal features. The results identify a complex array of natural and human-driven biases that greatly influences our understanding of the Palaeozoic chondrichthyan fossil record. Variation in completeness impacts on the utility of characters for assessing phylogenetic relationships of the various chondrichthyan groups, specifically the stem-chondrichthyan lineages. An extensive assessment of early chondrichthyan diversity patterns give greater insight on their environmental and biological drivers but also highlight the impact sampling biases may have on them. Together, the quantified macroevolutionary patterns of completeness and diversity draw a more comprehensive picture of the evolutionary history and nature of the early chondrichthyan fossil record.

Dinosaurs first appeared ~230 million years ago during the Late Triassic and dominated the global terrestrial ecosystems before the non-avian dinosaurs went extinct at the Cretaceous-Paleogene extinction. Given the broad geographical distribution and temporal range of non-avian dinosaurs, clarifying their feeding mechanisms and diets is essential for a fuller understanding of the macroevolution of non-avian dinosaurs, their trophic relationships with the contemporaneous organisms, as well as the global Mesozoic ecosystem. Oviraptorosauria is a clade of non-avian theropod dinosaurs that blossomed during the Late Cretaceous. Despite the long history of discovery, their diets remain controversial as the skeletons do not display obvious feeding adaptations. In this study, the mandibular anatomy and functional morphology of oviraptorosaurs are examined using approaches such as comparative anatomy, digital visualization and modelling, geometric morphometrics, and finite element analysis. It explores the feeding of oviraptorosaurs in the broad context of non-avian dinosaurs, compares the edentulous mandibles of phylogenetically distant vertebrates for dietary inference in oviraptorosaurs, identifies and describes an oviraptorid embryo exquisitely preserved inside an egg, and lastly estimates the bite forces of oviraptorids using musculature modelling. The results demonstrate that the feeding apparatus of oviraptorosaurs were functionally versatile, which facilitated niche-partitioning among contemporaneous oviraptorosaurs and other terrestrial vertebrates.

We understand plate tectonics by understanding relative plate motion at the plate boundaries, and the processes occurring there. Diverging plate boundaries are classified according to their spreading rate, with two broad categories as fast or slow-spreading. While fast-spreading is considered dominantly a magmatic process, faulting is much more important during slow spreading, leading to a far rougher, more rugged and more three-dimensional seafloor morphology which together with the large acoustic impedance contrast between basement and seawater, presents a severe seismic imaging challenge, with scattering of energy by the rough seafloor, velocity distortions from the rugged seafloor and strong side-coming events from the three-dimensional topography. Overcoming these challenges is critical to determine the geometry, extent, and mechanics of the faults, including large offset normal faults, called oceanic detachment faults (ODFs). As their footwalls - known as oceanic core complexes (OCCs) - consist of plutonic gabbros and mantle rocks, the fault must root beneath the crust. Their dimensions in the spreading direction indicate large offset, together suggesting that ODFs locally take up much of the plate divergence, but key questions remain about their geometry, mechanics, and lateral extent. This thesis addresses these issues and the challenge of seismic imaging of slow-spread crust in the 13° N area of the Mid-Atlantic ridge through a study of two oceanic detachment faults (13°20' N and 13°30' N, shortened hereafter to 1320 and 1330). A processing scheme - consisting of downward continuation to collapse side-swipe diffractions, followed by amplitude muting to remove them, deconvolution and velocity filtering processes - was developed to allow 2D seismic data to resolve the fine structure of the detachments, to suppress side-coming events, to reveal the geometry of ODFs in depth, and to determine the lateral extent of the detachments and the interaction between neighbouring detachments. The fine structure of the ODF was resolved to be anastomosing subsurface features, consistent with the latest ideas for the origin of the corrugated surfaces. Depth imaging shows that ODF steepen smoothly downwards from the low-angle of the exposed OCC to dips of ~60° at depths of ~5km, projecting to the bands of micro-earthquakes observed, a geometry everywhere consistent with slip-angle allowed by rock mechanics. Finally, Imaging on four intersecting profiles outline the extent of the two ODFs (1320 and 1330) in the slip and isochron direction showing the 1320 ODF cuts across and deeper than the 1330, in agreement with micro-earthquake data that show it is active while 1330 is not but suggesting they could have been linked in the past.

Granite petrogenesis is a fundamental Earth process that underpins the construction and evolution of the continental crust. Understanding how granites are generated and structurally emplaced is key to answering the question of how the continental crust has grown throughout geological time and can also provide insights on tectonic and geodynamic processes; styles of mineralisation; and the interaction between the Earth's mantle and crust. The study of granite petrogenesis is also deeply influenced by the experience of the researchers that engage in this field. For researchers from minoritized backgrounds, pursuing scholarly studies in the Geosciences, a disciplinary area with a documented lack of diversity in the context of UK higher education, can be experienced as particularly challenging. This thesis presents a dual approach which examines both the fundamental Earth process of granite petrogenesis as well as documenting and reflecting on the perspective of the author as a researcher from a diverse, intersectional background. A variety of research designs are employed including: rock magnetics to provide novel structural data to link granite petrogenesis to tectonics; geochemistry to investigate the sources of granitic magmas and their evolution in the continental crust; review of the literature to examine equity, diversity and inclusion in the Geosciences; and finally, autoethnography to document and provide reflection on individual experiences and challenges and proposed solutions to the persistent inequities in the wider field. The findings of this thesis suggest that parallels can be drawn between constructing the continental crust and building diversity in the Geosciences. Just as granite petrogenesis and emplacement is often pulsatory and incremental in nature, efforts to address structural inequalities, systemic discrimination and exclusionary cultures within academic Geoscience are shown to be equally episodic and prolonged by institutional inaction, departmental unaccountability and personal biases deeper-seated than the continental crust itself. In order to improve our understanding of granite petrogenesis and enhance equity, diversity and inclusion it is paramount that intersectional approaches are applied in future work, both in terms of research methodologies and the frameworks by which we acknowledge individual's different experiences and identities within the academic Geosciences.

The Cryogenian Period in Earth's history extended from approximately 720 to 635 million years ago and was characterized by extensive global glaciations, known as 'Snowball Earth'. During this time life not only survived but appears to have diversified, staging the conditions for the development of animals in the subsequent Ediacaran period. The mechanisms and habitats that enabled microorganisms to survive and diversify through this time are not known. Cryoconite holes, diverse and robust habitats on glacier surfaces, have been proposed as a candidate refuge habitat as the communities within support both photoautotrophy and heterotrophy, and can survive complete freezing. DNA sequencing, lipid analysis and laboratory incubation of cryoconite communities from both poles identified key eukaryotic crown taxa and provided evidence for how microorganisms could have survived during Snowball Earth. The application of 16S rRNA and 18S rRNA gene high throughput sequencing and intact polar lipid analysis enabled evaluation of the richness, relative abundance and biogeographic distribution of microbial communities across both poles to higher resolution than ever before. The Arctic and Antarctic cryoconite holes harboured distinct microbial communities, but the various biotic niches (grazer, predator, photoautotroph, chemotroph) are filled in every location. Eukaryotic keystone taxa that had emerged prior to the Cryogenian were identified across both polar regions. Laboratory experiments were used to incubate sediments from cryoconite holes under "Snowball Earth" physical conditions. The community responses were measured using oxygen sensors, comparative intact polar lipid analysis and quantification of 3H-Leucine incorporation. Community growth remained the same between Snowball Earth and modern polar conditions, indicating community resilience despite extreme cold and limited access to external resources. For cryoconite communities to have survived during Snowball Earth, the habitats that seed and distribute cryoconite must also have endured, particularly during glaciation and deglaciation. Signy Island of the maritime Antarctic South Orkney Islands was used as a model for these transitional habitats. Communities recovered from ponds, streams, ice margins and cryoconite on Signy Island did not thrive under Snowball Earth temperatures. However, DNA sequencing and intact polar lipid analyses revealed biodiverse and habitat-specific communities. The island presents a useful model for the networks of interconnected meltwater habitats during early glaciations and deglaciations of the Cryogenian. Through this combination of community DNA analysis and laboratory incubations, I present modern analogues for Cryogenian ecosystems, in which glacial surface ecosystems provide "diversity hotspots" that allowed the survival and proliferation of biodiversity during Snowball Earth.

Qatar is a desert where precipitation is uncommon and occurs mostly in winter. Qatar depends on desalination for drinking water and groundwater and recycled water for irrigation. There is overextraction of groundwater causing seawater intrusion. Re-use of treated wastewater (TWW) is extremely limited with only 14% of TWW being used for irrigation. This has led to the country disposing of unwanted water from various sources in artificial lagoons situated across the country where it evaporates and infiltrates the groundwater raising concerns over the possibility of environmental pollution. This is a unique situation that is limited to extremely arid countries. Research on the artificial lagoons is limited, with a noticeable knowledge gap in understanding the lagoon influence on Qatari aquifers. Accordingly, the hypothesis underpinning this research is that the quality and quantity of water in lagoons is currently having an impact on the groundwater reservoirs in Qatar. To validate this hypothesis a social survey, a hydrogeochemical survey and a microbial survey have been undertaken to establish the current situation and provide policy makers with recommendations for future lagoon management. A social survey was conducted through the distribution of online questionnaires to the public and conducting semi-structured interviews with policymakers responsible for water management in Qatar. The public had variable knowledge about the lagoons and expressed a willingness to learn more about them. Public and policymakers in Qatar agreed that there were both good and harmful consequences of the lagoons on groundwater and the environment. Policymakers' views differed, dividing into groups perceiving the lagoons as having the potential to degrade groundwater quality and those suggesting that infiltration of lagoon water would improve groundwater sources. Public opinion is important in lagoon management, thus policymakers agreed to raise awareness and incorporate public views with respect to water management in Qatar. Both public and policymakers encouraged the reuse of TWW and lagoon water and Qatar might leverage this approval to promote and extend its TWW reuse programs. A hydrogeochemical survey was conducted by sampling lagoons (n = 14) and wells (n = 54) in both the summer and winter of 2018 - 2019 (designated 'summer' & 'winter'). Water, soil and plants samples from sites irrigated with well water were analysed for multiple elements by ICP-MS. Major anions were determined by ion chromatography and organic and inorganic carbon was also measured. Lagoons violated the Qatari TWW reuse standards in terms of pH, TDS, TN, SO4 2- , Mn, and Zn. Groundwater samples violated WHO and Qatar drinking and irrigation standards in terms of pH, TDS, TOC, B, Ca, Cl- , Mg, Na, SO4 2- , As, Fe, Se, Sr, Tl, and U. Spatial and temporal variation in lagoons and groundwater salinization and water/rock process were visualised to illustrate the influence of lagoon water infiltration on adjacent aquifers. Soils (collected from close to lagoons and on farms) had Ni concentrations that violated EU and FAO/Who standards. Plant samples violated EU and FAO/WHO fodder standards in terms of Cr, Cu, Mn, Mo, Ni, Pb, Se and Zn. The multivariate statistical analysis revealed similar trends in the chemical variables of soils and plants from both farms and lagoons. Contamination from water and the environment tend to be higher in plants than in soil. A microbial survey was conducted using MALDI-TOF-MS to identify species of isolated bacteria strains (MacConkey and EMB selective media) collected from lagoons (n = 9) and wells (n = 13). Both groundwaters and lagoons were found to contain levels of coliform bacteria that exceeded national and international standards. Coliform bacteria in groundwater wells were observed to be associated with nearby lagoons, implying microbial infiltration. While the majority of the literature uses E.coli as a faecal indicator for wastewater contamination of groundwater, this research determined that P.aeruginosa is a more appropriate indicator in the Qatar lagoon context. In conclusion, this study examined three distinct scientific domains pertaining to the lagoon situation in Qatar: social, chemical, and microbial, with the goal that policymakers and managers in Qatar may benefit from the findings. Additionally, this research will serve as a baseline for future research and policy development for future lagoon management decisions in Qatar.

Mineral micronutrient deficiencies (MND), prevalent in Ethiopia and Malawi among most countries in sub-Saharan Africa, are linked to soil type. Dietary mineral intake is influenced by mineral content of edible portions of crops, and there is strong evidence that cereals grown in these regions have low uptake of micronutrients. The low nutrient uptake is attributed to soil conditions. Spatial information on soil and crop properties is therefore required to improve local estimates of MND risk in order to implement targeted and efficient interventions. Obtaining spatial information on soil micronutrients status and other relevant properties that affect their uptake requires substantial effort, and there are uncertainties in the resulting information, which depend, in part on the methods used for prediction and the sampling design. Therefore, it is necessary to use robust and efficient methods for spatial prediction which characterise the uncertainty of the predictions reliably. Furthermore, it is necessary that these uncertainties can be communicated effectively to stakeholder groups so that they can account for them at all stages from commissioning the survey through to making decisions based on the information. In this study, it was important first to understand how uncertain spatial information can be communicated to stakeholders (e.g., those in public health or nutrition and agronomy or soil science) through a systematic evaluation in the forms of maps. Evaluation of the test methods were done through a structured elicitation of the opinions of members of a stakeholder group about the usefulness of the methods. Stakeholders found that general measures of uncertainty, such as prediction error variances (e.g., kriging variance) were less clear than measures which integrated the uncertainty explicitly with the decision-e.g., the probability that the true value of a variable at a site if interest falls below a critical threshold. There was no evidence that they found verbal phrases these (e.g., "very uncertain") clearer than numerical values (i.e., a probability in the interval [0,1]). Following on this finding, it was necessary to examine how stakeholders interpret such probability information in more detail. Specifically, is it possible to estimate a probability threshold which a stakeholder group would choose to intervene, reflecting their assessment of the costs attached to errors of commission and omission? Further does this probability depend on framing of the problem (e.g., probability that a threshold is exceeded or that it is not exceeded) and does it depend on professional background of the stakeholder? In a designed experiment, stakeholders were presented with uncertain information on micronutrient supply from a crop, with the uncertainty expressed as a probability with positive framing (probability of adequate supply) or negative framing (probability of insufficient supply). The results showed that probabilities presented in a negative framing led to more conservative decisions, i.e., deciding to intervene at a much smaller probability of deficiency than if the equivalent probability of sufficiency were presented. The elicited probability threshold is prone to framing effects (i.e., how the question is posed), and that this effect interacts with professional group. The two components of this thesis described above showed how uncertain information can be effectively communicated to stakeholders to support decisions. The next task was to develop a framework for the planning, execution, and evaluation of surveys to address specific requirements of these stakeholders. This was based on a decision-theory approach to analyse the particular task, to identify the key uncertainties and their implications and so to enable stakeholders to ensure that an approach to survey would meet their needs. A particular task, based on research practices within the GeoNutrition project (Bill & Melinda Gates funded) was identified -the selection of the study sites to evaluate agronomic biofortification strategies for MND at selected sites based on soil soluble Se. The information required were analysed, and then the outputs of spatial prediction at national-scale of soil soluble Se by ordinary kriging, indicator kriging, linear mixed models and random forest were evaluated. There were substantial uncertainties by all three methods, and challenges with dealing with a complex statistical distribution. This work showed the importance of validation-internal and independent for understanding the suitability of spatial prediction to support decision making. Uncertainty should be considered when planning sampling for a geostatistical survey. It is important to consider how stakeholders can assess the implications of uncertainty in spatial predictions to determine appropriate sampling grid space for a geostatistical survey. Four approaches (offset correlation, prediction intervals, conditional probabilities and implicit loss functions), that can be used to assess the implications of uncertainty in spatial predictions using prior information on variability of the target properties, were presented to a diverse group of stakeholders in order to determine an appropriate grid spacing. There were variations in the selection made by each method. Some were not well understood. The one which stakeholder favoured, offset correlation, is not directly linked to decision making. More work is needed to develop sound but accessible ways to engage stakeholders with uncertainty consistent across planning and interpretation. Findings from this research will help in better understanding of uncertainties in the data obtained in the GeoNutrition projects thereby facilitating improved use and uptake of that information by decision makers in Ethiopia and Malawi. Better decisions will be made on sampling for such surveys in other countries which decide to undertake those using better methodologies for national-scale surveys of soil properties or similar environmental variables.

Astrobiology and the assessment of planetary habitability centres on the detection of organic matter as all known biological lifeforms on Earth are carbon-based. To understand how life began, and where else it may be found in the Solar System, requires knowledge of the origins of the building blocks of life (organic molecules). Mars is the most likely planet in our Solar System to host either extant or extinct life, thus the characterisation of its organics is key to improving our understanding of its habitability. Detecting organics has been a priority of Mars missions since the Viking era in the 1970s. There are two broad theories for the source of organic matter found both on Mars by rovers and in martian meteorites: martian carbon is exogenous, deposited on Mars from impacts of carbon-rich material, such as carbonaceous chondrites, or indigenous, originating from the reduced martian mantle. This thesis seeks to characterise the organic matter in martian meteorites, Mars analogues, carbonaceous chondrites, and ureilites, to determine the likely origin of martian organic material, and improve our understanding of the formation and processing of organics in the Solar System. In addition, by evaluating the protocols and techniques used to detect organic matter, this research demonstrates effective analytical workflows to maximise the scientific return from valuable planetary samples in anticipation of Mars Sample Return. This project has demonstrated that CHONPS, life's building blocks, and available on Mars through the detection of sulfur, nitrogen, and oxygen-bearing organic molecules in small samples of martian meteorites, and orthophosphate in Nakhla. Despite these compounds being formed through abiotic processes, this demonstrates that Mars has some of the key essentials for life to form. Macromolecular carbon (MMC) inclusions detected in the shergottites Tissint, NWA 8159, and SaU 008 are likely indigenous to Mars. Similarities between the STXM XANES peaks in NWA 8159 and previously published data from ALH 84001 demonstrate that abiotic synthesis of carbon has continued on Mars for at least two billion years. Raman and STXM XANES data from Tissint and the ureilites Goalpara and Hajmah (a) demonstrate the sensitivity of meteoritic organic matter to thermal processing, both on planetary bodies and during laboratory analysis. Results from the analysis of the bulk organic content of the nakhlites Lafayette and Nakhla, as well as CM chondrites, using liquid chromatography mass spectrometry (LC-MS) indicate the presence of a mixture of extra-terrestrial organic compounds in these meteorites. Organic sulfonates detected in Lafayette and Nakhla are consistent with sulfur-bearing compounds detected at Gale Crater on Mars by Curiosity's SAM instrument, as well as in Tissint, Nakhla, and NWA 1950 using time of flight secondary ion mass spectrometry. Numerous fatty acids detected with LC-MS in Nakhla and Lafayette show that Fischer-Tropsch-Type synthesis of organic matter probably occurred on planetary bodies. Results from the LC-MS analyses of Nakhla and Lafayette also reveal the presence of likely organic contaminants from the fall environments of these meteorites. Several plant-derived metabolites were detected in Lafayette, helping to constrain the fall scenario of this meteorite. The detectable presence of organic contaminants in small masses (< 40 mg) of martian meteorites which fell ~a century ago demonstrates the importance of careful curation of extra-terrestrial samples to minimise the ingress of terrestrial compounds. Results from LC-MS analysis of the Winchcombe meteorite also show the urgency of collecting environmental control samples from the fall sites of meteorites, when possible, to distinguish between organics indigenous to the sample, and terrestrial contaminants. LC-MS analysis of martian analogues stored in polyethylene sample bags also show evidence of plastic contamination during storage, illustrating the importance of comprehensive curation records, and the avoidance of any hydrocarbon-based storage for extra-terrestrial samples. The protocols used in this project demonstrate the effectiveness of a correlative in-situ workflow when studying organics in thin sections of extra-terrestrial samples, starting with optical microscopy and Raman spectroscopy to identify macromolecular carbon, and finally analysing functional groups at the nanoscale with STXM XANES. Non-destructive microscopy at the mm/μm scale reveals the context of organic material whilst nanoscale analyses with whilst STXM XANES show molecular details of organics, whilst only destroying ~tens of microns of precious samples. LC-MS is highly effective at non-targeted analysis of the bulk organic content of igneous materials. The extraction protocol developed in this project captures a wide range of metabolite classes in all four meteorites studies, as well as the martian analogues.

Eruption records are crucial to understanding volcanic output and eruptive processes over time. However, due to a diminishing longer-term record of explosive eruption deposits, often due to burial, erosion and cover, volcanic histories are regularly incomplete thus limiting our understanding of eruptions and their effects through time. This is particularly detrimental for densely populated regions at risk from volcanic activity. Mexico City is one of the largest populations in the world and sits within one of the major intracontinental volcanic arcs. Risk from diverse eruptions is high, however eruption records are limited due to poor exposure. This thesis, therefore, improves upon these records by combining stratigraphic, geochemical, and geochronological results. To achieve this, a c.500 m lacustrine core from Lake Chalco, Mexico City is probed in order to construct a detailed tephrastratigraphy and volcanic stratigraphy of the succession. It is found that volcanic deposits account for 59.81% of the composite core, comprising a maximum of 603 tephra layers, along with laharic and coarser-grained volcaniclastic facies and lavas. Volcanic output is assessed using a novel methodology and reveals that the frequency of explosive eruption deposits in the lake has generally waned over time. Fieldwork was conducted at several volcanoes, including Popocatépetl, Iztaccíhuatl, and Tláloc-Telapón, in order to sample and obtain glass geochemical data to fingerprint possible volcanic sources of explosive eruption deposits at Lake Chalco. All three volcanoes revealed distinct fingerprints and supplementary 40Ar/39Ar dates extend the older eruptive histories of these volcanoes. Core tephras were also geochemically investigated, with 137 layers analysed for major element glass geochemistry. It is revealed that Nevado de Toluca and La Malinche volcanoes are not chemically distinct from Iztaccíhuatl, so the three volcanoes have to be grouped for correlation with the core. Of the 137 tephras analysed at Lake Chalco; 35 are from Popocatépetl, 43 from either Iztaccíhuatl, Nevado de Toluca or La Malinche; 1 from Tláloc-Telapón; 17 from the nearby monogenetic Sierra Chichicnautzin Volcanic Field; 3 from Los Humeros caldera, Mexico and 1 from Atitlán caldera, Guatemala. Amongst the analysed tephras, two well-dated and widespread eruptions (isochrons) are correlated into the Chalco succession: (1) the Xáltipan ignimbrite from Los Humeros and (2) the Los Chocoyos (LCY) eruption from Atitlán. Further to these chronological markers, 12 samples (plagioclase and groundmass separates) have been submitted for 40Ar/39Ar dating, although results are yet to be finalised. This study significantly builds upon the eruptive history of the Mexico City region, identifying and characterising many newly identified eruption layers as well as correlating others. The results of this thesis are of direct relevance to hazard assessment for Mexico City, providing a longer-term assessment of explosive volcanism that has directly impacted the region in the past. The methodology used in this study may also be replicated in other regions, and sedimentary successions containing volcanic deposits.

Salt collapse structures host significant hydrocarbon reserves and have enormous economic importance, however despite this there is comparatively little research conducted on their evolution, structure and facies distribution. This thesis provides and in-depth multidisciplinary study on the influence of halokinesis upon the sedimentology of the Upper Jurassic Fulmar Formation of the Central North Sea. The thesis will: 1) examine the temporal and spatial variability of facies within and between salt collapse structures; 2) relate any observed facies variations to subsidence (salt withdrawal) and sedimentation rates; 3) and aim to produce predictive models of likely reservoir distribution, quality and connectivity that are applicable to the salt basins. The Central North Sea area was selected for this study due to its extensive history of hydrocarbon exploration and production. This history has given rise to numerous, closely spaced wells and fields, providing the rare opportunity to conduct a detailed sedimentological study on the impacts of halokinesis on shallow marine sandstones. Results from the study provide a new tectonostratigraphic model for the evolution of the West Central Shelf and the Central Graben, highlighting the importance of subaerial erosion on the West Central Shelf in creating salt collapse structures. This salt influenced topography was determined to be the dominant control on the preservation of the Fulmar Formation, with evidence from the Mallard Field showing the importance of these palaeovallys in preserving the Fulmar Formation. A regional sedimentological analysis indicates that facies belts occur on a scale greater than singular collapse structures, suggesting the initial deposition of the Fulmar Formation would have been much more widespread. The study reveals a clear and observable relationship between facies deposition, preservation and salt dissolution. In instances where salt dissolution rates are equal to sedimentation rates regional facies trends continue unabated. In situations where dissolution rates exceed the sedimentation rate deep water fine-grained sediments dominate, conversely where dissolution rates are outpaced by sedimentation rates erosion of the sediment occurs. The study hypothesises a 'Goldilocks' zone in which sedimentation and subsidence rates are balanced in such a way that preferred facies are deposited and preserved from later erosion. The results presented here add to the growing body of literature surrounding salt collapse structures globally, and in particular can be used to mitigate risk during hydrocarbon exploration.

Sedimentary basins are an important geological archive as they contain a wealth of information about the regions palaeogeographical setting, thermal evolution, and post depositional history, which are critical to many geological applications. However, establishing the source(s) of the sedimentary material stored within a basin, can be complicated by the refractory nature of some minerals often used as proxies for sediment provenance, meaning that a recycled component may be present and difficult to recognise. Thermal and burial history reconstructions based on the maturation of organic matter (vitrinite reflectance, VR) has been applied widely by the hydrocarbon industry to great success. However, due to the techniques inability to supply a quantification on time, its application in regions that lack post depositional constraints can lead to differing interpretations. In this thesis two geochronometers (zircon and apatite U-Pb geochronology) and one thermochronometer (apatite fission track, AFT) have been applied to the Carboniferous sedimentary strata of the central and eastern regions of the Midland Valley of Scotland. The aim of which is to provide a better understanding of the evolution of post-Caledonian sediment source(s) and pathways and to better constrain the post-Carboniferous thermal histories of the Midland Valley. This will reduce the geological uncertainties associated with the region, which is vital for Scotland to meet its future low carbon geo-energy commitments. A multi-proxy approach, applying U-Pb geochronology to detrital zircon and apatite has been utilised to investigate and constrain the provenance of the clastic material in Viséan to Westphalian B, Carboniferous sandstones of the Midland Valley of Scotland. The results of this provenance data clearly show three distinct sources for the sandstones: 1) Laurentian associated rocks (~900-2000 and ~2500-3100 Ma), 2) Caledonian orogeny associated rocks (395-475 Ma), and 3) Carboniferous volcanic associated rocks (~330-350 Ma). Applying U-Pb geochronology to both zircon and apatite from the same sandstone has allowed for the identification of recycled components, indicating that not all U-Pb age populations have been derived directly from their original source. Detrital zircon UPb age peaks that align with the Grenvillian (900-1200 Ma), Pinwarian (1450-1510 Ma), Labradorian (1600-1700 Ma), and Lewisian (2500-3100 Ma) orogenic events, lack equivalent apatite U-Pb counterparts. This suggests that Laurentian associated populations have been derived through the recycling of existing sedimentary and metasedimentary lithologies from the Devonian Old Red Sandstone, Grampian terrane, and Southern Uplands. Samples with complementary prominent Caledonian orogeny associated zircon and apatite U-Pb age peaks, are likely to be derived from first cycle sources from north of the Midland Valley, while Carboniferous ages are most likely derived from volcanic sources within the region. Spatial and temporal variation in the sample detrital spectra, indicates the provenance source did not remain constant over time. Early-mid Viséan (ArundianAsbian) U-Pb zircon samples are dominated by Proterozoic and Archean, Laurentian associated ages and lack a significant Caledonian peak, indicating recycling of Devonian Old Red Sandstone, Grampian terrane, and Southern Uplands dominated the sediment supply. U Pb apatite samples from the same time are dominated by a Caledonian peak suggesting either a very minor Caledonian associated source was actively supplying a limited amount of sediment or recycling of apatite through existing sedimentary lithologies is possible, as previous investigations have shown late Devonian Old Red Sandstone to be lacking in Caledonian aged U-Pb zircon. Late Viséan (Brigantian) samples in the eastern Midland Valley of Scotland have a marked increase in Palaeozoic Caledonian associated zircon ages, indicating the source region now included first cycle Caledonian associate rocks, although Laurentian associated components still dominate the spectra. A Brigantian sample collected to the west of the Bathgate Hills Volcanic Formation, located towards the centre of the study area, still shows a paucity in Caledonian related zircon ages, suggesting the volcanic high was a barrier or at least hindered sediment from the northeast being deposited across the region. Carboniferous peaks present in Brigantian zircon and apatite samples indicate the volcanic highs were also local sediment sources. A major change in sediment provenance occurs during the early Namurian (Pendleian) evidenced by the reversal in the dominant source signal, with Laurentian associated ages now relatively insignificant compared to Palaeozoic peaks, indicating first cycle Caledonian associated rocks now dominated the source area. A similar signal is recorded in Carboniferous strata in the Millstone Grit Formation in the Pennine Basin, attributed to a regional source to the north supplied via the Pennine delta. This distal source was also likely supplying material into the Midland Valley as well as proximal sources from Scottish Caledonian rocks, which combined to drown out the recycled component. Caledonian ages continue to dominate the Midland Valley samples in the Westphalian, contrary to Carboniferous basins to the south, which experience a reduction in the influence from the northern source during the Westphalian. Sources that dominated basins to the south were most likely prevented from entering the Midland Valley of Scotland by the Southern Upland high, which allowed the Caledonian sources to prevail. Undertaking detrital thermochronology is challenging due to the low yield of accessory minerals in some sedimentary rocks. However, results show AFT ages from the Midland Valley of Scotland reflect the geological structure of the region during the Carboniferous, with oldest ages located within the syncline cores and on structural highs. A complex series of forward and inverse modelling of individual and multi-sample profiles, combining outcrop and borehole samples, suggests the thermal histories can be sub-divided into three episodes: 1) Carboniferous Permian heating, 2) PermianMesozoic Cooling, and 3) Cenozoic cooling. . Inverse models also suggest initial heating was under the influence of an elevated geothermal gradient, supported by Carboniferous volcanic activity. These episodes are similar to those reported in other thermochronology investigations for onshore Scotland and show a contrast to those reported offshore, suggesting the onshore region was cooling as a coherent block from post Carboniferous times. Though the general trend observed in profile models is one of cooling through the Mesozoic, indicating an absence of significant burial under continued successions, some individual samples display an element of late Mesozoic reheating, which may be attributable to the Late Cretaceous transgression. The final Cenozoic cooling pulse, evident across the region, has been recognised in numerous investigations and has been attributed to processes associated with the emplacement of the proto-Icelandic plume or far field stresses related to compressional forces associated with the opening of the North Atlantic Ocean and Alpine collision. However, the temperature sensitivity of AFT is not enough to resolve this part of the thermal history. The results reported in this thesis reveal that the provenance of the Carboniferous sedimentary strata of the Midland Valley of Scotland did not remain constant through time and that post burial thermal maximum was attained following Carboniferous burial under an elevated geothermal gradient which was followed by episodes of cooling. These findings have important implications for assessing the future geo-energy potential within the Midland Valley of Scotland.

Past lacustrine and wetland sediments from arid regions, sensitive to changes in precipitation and evaporation, are important archives of past environmental variability. This thesis presents new data that contribute to the Quaternary records of Jordan through multi-proxy analyses of sediment archives from two study sites in southern Jordan; the Gharandal Valley and the Dead Sea Basin. Through detailed analyses of the sediments from the two study sites, the depositional environments, environmental conditions, and how these changed, and to some extent their timing were reconstructed. Sediments from the Gharandal Valley were investigated and collected from five different sedimentary sections (> 30 m sediments) and analyzed for particle size distribution, organic and carbonate content (through LOI), and elemental (through XRF) and minerogenic (through magnetic susceptibility) composition. The results indicated complex tectonic/climate-driven depositional environments prevailed in the valley, during Marine Isotope Stage (MIS) 6, alternating from fluvial in-wash to fluvio-aeolian and wetland deposition following the proposed valley outlet damming. The GH1 and GH2, the main sections in the valley, record the environmental aggradation from stream-fed wetland depositional conditions where thin wetland beds developed following in-wash events, in the lower parts, into more consistent wetland (wetter) conditions towards the top of the sections. These cycles were identified in 16 fining upward primary associations in the GH1 section and 8 fining upward primary associations in the GH2 section. The age estimate (MIS6) is consistent with wet phases recorded elsewhere in the Levant and increased monsoon precipitation recorded in southern Arabia suggesting that an influence of the two systems (the northeastern Mediterranean Cyclones and the southern tropical monsoon), which do not reach the valley site today, may have contributed to maintaining the wetland conditions in the valley during glacial stadials and interstadials. From the eastern side of the Dead Sea Basin (DSB), the lacustrine section DS1 was investigated. The section is primarily comprised of laminated pale and dark laminae and laminated detrital laminae with a thick gypsum-dominated bed. Considering the different nature of the sediments, the DS1 bulk sediments were first analysed using proxies mentioned earlier for the Gharandal Valley. In addition, the pale laminae were analysed for the carbonate isotope composition (δ13C and δ18O), mineralogy (through XRD) and carbonate crystal habit (through SEM EDS) analysis. Through preliminary U/Th dating of aragonite laminae, the DS1 section age was estimated at ca. 40 ka to 37 ka (MIS3). This places the section as part of the Lake Lisan Middle Member (ca. 58 ka to 31ka). Based on the sediment's lithology and the multi-proxy records, the environmental history of the DS1 section, of enhanced/reduced freshwater input into the lake (P/E ratio) at millennial, centennial and close to annual scales, is recorded in four distinct lithostratigraphic units. The units record relatively high lake levels, then lake level lowering and the deposition of the gypsum bed, a lake re-filling stage and return to stable relatively high lake levels. The environmental proxies suggest that during Greenland Interstadials (GIs), the lake level was relatively higher than during Stadials (GSs). The gypsum bed, the lowest relative lake level in the record, probably coincides with Heinrich Event 4. At centennial scales, the environmental proxies apparently record lake level changes corresponding to the GIs indicating variable amounts of freshwater reaching the DSB. An initial assessment of the moisture source was done based on the aragonite initial 234U/238U ratios variability and indicated the dominance of the Eastern Mediterranean cyclones in driving the deposition of the DS1 section. The results of this thesis emphasize southern Jordan's sedimentological and palaeoclimatic heterogeneity and the complexity of the past environmental records that can be recovered. This indicates the need for continued investigations and particularly more dating control, based on more comprehensive and detailed approaches in order to achieve a better assessment of the Quaternary sedimentological and environmental variability in the region.

Atomic-scale defects can control the exploitable optoelectronic performance of crystalline materials, and several point defects in diamond are emerging functional components for a range of quantum technologies. Nitrogen and hydrogen are common impurities incorporated into diamond, and there is a family of defects that includes both. The N3VH0 defect is a lattice vacancy where three nearest neighbor carbon atoms are replaced with nitrogen atoms and a hydrogen is bonded to the remaining carbon. It is regularly observed in natural and high-temperature annealed synthetic diamond and gives rise to prominent absorption features in the mid-infrared, the strongest of these being its C-H stretch mode at 3107 cm-1. Often, it is observed alongside another feature at 3237 cm-1. This feature is presently unidentified, but speculated to belong to an N-H stretch. Here, we combine time- and spectrally resolved infrared absorption spectroscopy to yield unprecedented insight into the vibrational dynamics of both of these defects, following both infrared and ultraviolet excitation of the C-H stretch. In doing so, we gain fundamental information about the energies of quantized vibrational states and corroborate our results with theory. We map out, for the first time, energy relaxation pathways, which include multiphonon relaxation processes and, in the case of N3VH0, anharmonic coupling to the bend modes. These advances provide a new route to probe and quantify atomic-scale defects in diamond.

This thesis addresses the macroevolution of coccolithophores during two significant cooling periods of the Cenozoic: the Eocene-Oligocene Transition (EOT) and the Neogene to Recent. New onshore low-latitude site NKK1, from the Indo-Pacific Warm Pool (IPWP) in the Indian Ocean, documents high-resolution calcareous nannofossil assemblage responses during the EOT. Data from NKK1 consists of detailed high-resolution species relative abundance records documenting the late middle Eocene to early Oligocene, with well-preserved nannofossils. Research on tropical calcareous nannofossil assemblages through the EOT where sediments yield good recovery and well-preserved coccoliths, is uncommon and so NKK1 presents valuable new palaeoceanographic, palaeoecological, palaeoclimatic and biostratigraphic data from calcareous nannofossils across the EOT. Through this time interval species diversity declined coincident with the extinction of rosette-shaped discoasters (~34.44 Ma) termed the Discoaster extinction event (DEE). This interval, during the early EOT, represents the decline of oligotrophic taxa due to increased nutrient supply from the Southern Ocean; additionally, an abundance decrease is observed in small (< 3.5 μm) Reticulofenestra morphotype cell sizes through the DEE interval - signifying coccolith size was apparently not limited by atmospheric CO₂. Additionally, a combination of two datasets offers a global perspective to assess the macroevolutionary drivers influencing coccolithophore lineages during declining atmospheric CO₂ through the late Neogene. The first is a compilation of ~2.5 Ma time-slice data from ocean sediments recovered at 9 sites across the Atlantic, Indian, Pacific and Southern Ocean basins that spans the last 15 Ma. The second is a high-resolution (200 ka) dataset from Integrated Ocean Drilling Program Expedition 363, Site U1482, where a continuous sedimentary sequence encompassing the crucial late Miocene to early Pleistocene (7.7-1.7 Ma) interval yields a well-preserved, sub-tropical high diversity calcareous nannofossil assemblage. These two records provide supporting evidence that declining pCO₂ had a significant impact on evolution within the Noelaerhabdaceae family with a correlation between atmospheric CO₂ and a decrease in Reticulofenestra coccolith size observed since the late Miocene. Through the Plio-Pleistocene however, the rise of small Gephyrocapsa spp., an upper euphotic zone species, is correlated with the rise in deep-photic zone dw₂₂ that drives major macroevolutionary turnover in dominance, but that a deepened nutricline exerted as much of a selective pressure as pCO₂ with potential impacts across multiple lineages including the extinction of Discoaster spp., demise in Reticulofenestra groups and the modern dominance of Florisphaera profunda - Gephyrocapsa assemblages.

Over the years, the continuous expansion of cities has drawn the attention of engineers and researchers to the need to support sustainable planning. As cities expand, they would be more prone to geohazard risk, which could cause severe costs. Therefore, a system to provide information of geohazard risk could support sustainable urban planning. A suggested application is proposed in this thesis to assess settlement risk caused by tunnelling. A framework methodology is proposed to aid the assessment of urban geohazard risk. The settlement risk assessment analyses and the associated building damage and cost assessment form the structure of the framework. Building Information Modelling (BIM) provided and supported the information for the data processes used in the whole analysis and the 3D geology-tunnel-building model creation. The resulting risk assessments are presented using 3D visualisations. From these visualisations, further investigations could be focused on the 'higher-risk' outcomes presented. This forms a preliminary assessment a tool. The final oucome of this research is an integrated information system based on advanced analysis and 3D modelling tools for urban geohazard risk. The research also provides information which contributes to knowledge and understanding for relevant associated problems and supports sustainable decision-making.

The mobilisation and intrusion of salt plays a major role in the evolution of basins. Although the geometry and distribution of salt structures can be easily examined, the internal dynamics of salt intrusion are only partially understood. Collecting detailed structural data from outcrop is difficult due to limited exposure, inaccessibility, and poorly preserved visible fabrics. To overcome this crucial impasse in salt tectonics, detailed and high-quality strain data is required from salt outcrops. To obtain structural strain data we have used anisotropy of magnetic susceptibility (AMS) measurements on oriented samples collected from mine and coastal exposures of Carboniferous evaporites in Nova Scotia, Canada. With any AMS study it is important to have a grasp of the magnetic components of the rock. Further magnetic techniques, along with chemical analyses, have been used to better constrain these magnetic properties. Out-of-Phase AMS was also applied for the first time on diamagnetic rocks and rock with very small ferromagnetic fractions to untangle the ferromagnetic fabric from the whole rock. It is unusual to find diapiric structures so well exposed as they are on the west coast of Cape Breton, Nova Scotia. These evaporites overlay a predominantly halite diapir core and are surrounded by Carboniferous sediments. Deformation within the gypsum deposits reflect deformation of the underlying halite core of the diapir and the overall structure. Both brittle and ductile deformation fabrics have been recorded within the surrounding sediments and we have observed them imprinted within the evaporite facies. To understand the magnetic fabrics these are detailed and assessed in relation to AMS. 3D Models have been created using aerial drones and photogrammetry to help understand the scalar relationships between fabrics and geological structures related to halokinesis. Pugwash mine offers a perfect opportunity to study diapiric growth structures at a much larger scale. Using 5 maps and 3D photogrammetric models at different depths we can better understand the deformation of the deposit and the 3D geometries formed. Similar experimental methods to those described above have been used to ascertain the strain recorded by the detrital material within the halite samples. This study provides evidence for AMS being a fast, quantitative approach to studying deformed evaporitic deposits.

During the Pliocene (5.33−2.58 Ma), the NE Atlantic and Nordic Seas witnessed a transition from enhanced warming, whereby surface temperatures were up to 8°C warmer than present, to cooling associated with the intensification of the Northern Hemisphere Glaciation. Currently, there are few reliable multiproxy datasets to document this change, and a notable mismatch between data- and model-based temperature reconstructions. This thesis develops a new palaeoclimatic, palaeoceanographic and palaeogeographic understanding of this region during the Pliocene by geochemical fingerprinting of marine and terrestrial sediments. First, new benthic foraminifera δ\(^{13}\)C and authigenic εNd records are used to assess tectonic and climatic controls on deep-water connectivity between the NE Atlantic and Norwegian basins. Secondly, new alkenone and TEX86 records are used to evaluate the magnitude of warming, and to unravel whether data/model discrepancies are attributable to proxy biases. Thirdly, brown coals from the Pliocene Tjörnes Beds in northern Iceland are investigated to establish whether they preserve branched GDGTs capable of reconstructing terrestrial temperatures. Together, these results suggest climatic events are at least as important as tectonic events in driving regional oceanic circulation at this time, and reveal data/model discrepancies are influenced by warming biases, associated with the analysis of low concentration alkenones.

Landslides are one of the most common natural geological hazards in the world, which result in detrimental consequences and significant damages to human life and properties every year. In many occasions, due to extensive runout of the landslides, substantial destruction can be imposed on nearby structures. Therefore, understanding post-failure behavior of landslides is significantly important as it allows for the prediction of possible catastrophic consequences and timely planning of the disaster mitigation measures. In numerical modeling analysis, reliable prediction of landslides post-failure behavior is significantly difficult due to its large deformation, inherent heterogeneity of soils, and their complex spatially varying multiple geological properties that are internally correlated with each other. The natural heterogeneous structure of soil mass makes the landslides post-failure behaviour highly random and haphazard. However, current simulation methods cannot accurately investigate the post-failure deformations. In this thesis, a new integrated probabilistic computational framework, based on the stochastic material point method, is developed to evaluate the post-failure behavior of landslides considering the effects of heterogeneous soil properties. Material point method is used to simulate the large deformations during and after the landslide failure. The spatial variability in the parameters of soils is modelled by random fields, which are discretized by Cholesky matrix decomposition method to incorporate the effects of the soil spatial heterogeneity on the post-failure deformations. A Monte-Carlo simulation is adopted to generate series of random fields with soil properties. In the computational framework, monovariate, bivariate, and multivariate geotechnical random fields are implemented to investigate the effect of different spatial varying soil properties. The capabilities of the framework in postfailure modeling are illustrated by applications to modeling heterogeneous sand collapse, v clay slope with undrained condition, and cohesive-frictional slopes. It found that the spatial varying soil properties notably influence the post-failure behavior of landslides/flows. It is demonstrated that the uncertainty of runout distance increases with the increase of coefficient of variation for soil properties. In addition, a practical landslide hazard zoning is conducted to quantitively evaluate the level of disaster for facilities or structures located in the vicinity of the slope by using the exceedance probability of influence distance and runout distance. Five categories based on different thresholds of exceedance probability are used to visualize the area potentially affected by the landslide. In comparison, the deterministic analysis particularly underestimates the post-failure behavior and the runout motions, which may give an nonconservative estimation of the potential risks for structures located in the vicinity of slopes. Moreover, the framework allows the user to consider soil interdependent anisotropy and fabric orientation in assessing the post-failure behavior of a landslide. Not only the magnitude of uncertain soil properties, but also the orientations of soil stratification are considered, which shows the proposed method is capable of reproducing the post-failure behavior of landslides with different rotational layer of heterogeneous soil. The findings highlight the importance of considering the orientation of soil stratification, rather than only the magnitude of shear strength, in analysing the runout motions of a landslide. Furthermore, based on sparse field geo-data, dependent random variables are cross-correlated using a multivariate copula function to capture their unique internal dependence structure, the use of which provides a more accurate representation of the interdependent properties of randomly-distributed soil in large-deformation modeling analysis. The results indicated that the cross-correlation and dependence structures among soil properties on the accuracy of post-failure behavior of landslides are significant and should not be ignored.

This thesis provides an account of the ongoing effort to define the Anthropocene as a formal geological unit. Coined in 2000 by the atmospheric chemist Paul Crutzen, the term 'Anthropocene' has become symptomatic of a critical-theoretical zeitgeist: from a warning concerning the "deep time" effects of anthropogenic climate change, to an epistemological critique of the "human subject". It is a theme that has taken on significance in critical legal theory as well. I respond to these debates, focusing on a component of the Anthropocene thematic that is often overlooked: the political, legislative, and historical dynamics of geology as a scientific discipline. Beginning in the seventeenth century, techniques such as fossil correlation and the relative ordering of earth's material deposits have redefined understandings of scriptural authority, bringing geoscience to bear on the predominant existential reckonings of the day. Since 2008, the Anthropocene Working Group (AWG), a team of geologists, Earth System scientists, historians, and also including a lawyer, have been compiling a proposal to include an Anthropocene unit within the Geological Time Scale, the formal guide for the designation of time and space over 4.5 billion years of earth history. Folding contemporary concerns and events into transhistorical deep time, the AWG's formalization effort can be seen as an attempt to advance novel strategies of geoscientific classification in a manner continuous with contemporary social anxieties. Engaging the formalisation effort as a legislative exercise, I provide a genealogical account of the evaluative procedures in which the formalization of an Anthropocene unit is situated, and engage participant observation of the AWG, tracking the controversies, negotiations, and procedures involved in their effort to ratify a new geological unit. Ultimately, I argue that the effort to define an Anthropocene unit unfolds as a process of refiguring the significance of geoscience in society.

This PhD is a contribution to the rapidly expanding application of sedimentary ancient DNA (sedaDNA) as a tool for palaeoecological reconstruction. Using the current understanding of preservation of sedaDNA within lacustrine sediments, this PhD applies the technique to three case studies from fluvial (Brown Bank) and intertidal (Tan-y-Bwlch and Orkney) depositional environments often considered problematic for conventional proxy analysis as a methodological approach for testing the framework of sedaDNA preservation. This PhD examines both the taxonomic output and the approaches for understanding preservation of sedaDNA. As a comparative, conventional proxy datasets such as pollen and diatoms are analysed to examine the overall preservation potential across the sedimentary sequences and as means to compare taxonomic outputs and provide overall assessment of the complementary role of sedaDNA for palaeoecological reconstruction. As part of this PhD, the MetaDamage tool is presented as a new tool to undertake DNA damage analysis on a metagenomic scale as meant to provide additional confidence in the assessment of the sedaDNA outputs. The results of this PhD demonstrated low level preservation and low taxonomic diversity of sedaDNA associated with vegetation across the Brown Bank, Tan-y-Bwlch and Orkney sedaDNA analysis. The assemblage that is presented demonstrates ancient DNA relating to the plant growth within the sequences described above, supporting the current understanding of a localised mechanism for deposition and preservation. Although limited by inconsistent comparative conventional proxy datasets, this PhD also demonstrates a patterning of preservation within highly organic matrices, leading to the formation of testable working hypotheses for future work. This PhD is a demonstration of the challenges of applying theoretical models for proxy archive formation and the reality of an output of working within depositional environments that are often considered problematic for palaeoenvironmental reconstruction. It is clear from this sedaDNA analysis that there is potential for preservation within fluvial and intertidal deposits, and that there is future work to be undertaken to better understand the mechanisms for sedaDNA preservation within these depositional environments.

Until ~7000-8000 years ago, much of the southern North Sea was a coastal plain now named Doggerland. Doggerland was inhabited by Mesolithic people and is expected to be a rich source of archaeological information. This thesis reconstructs environmental changes through time in a region of Doggerland using sedimentary ancient DNA (sedaDNA) from marine cores. Plant and animal DNA profiles are produced for individual samples using a novel, highly accurate sequence assignment method. These are used to infer environmental conditions and changes through each core. Patterns across cores are then examined. The validity of these results is evaluated by searching for age-associated DNA damage patterns and evidence that DNA has not moved vertically between sediment strata. Certain unexpected taxa that would be particularly informative for climate or human activity are investigated in greater depth where data allows. Finally, the authenticated results are drawn together and re-examined in the context of preliminary dating information from Europe's Lost Frontiers colleagues. Overall, the cores appear to have captured environments through the inundation process. There are woodland and freshwater profiles; some are grass dominated and may represent reed beds; others combine seagrasses and small terrestrial signals to imply a brackish coastal environment. The project presents a detailed insight into an ancient submerged landscape, demonstrates the capability of emerging sedaDNA analysis methods, and provides a platform for further investigation of the relationship of sedaDNA to other environmental proxies.

The monitoring of land motion can provide critical information on potential geological hazards. Geohazards are phenomena that can pose significant socio-economic and environmental risks. There have been an increasing number of geohazard mapping programmes across the world that utilise space-related technologies, such as the Global Navigation Satellite System (GNSS) and Earth Observation (EO). Differential interferometric synthetic aperture radar (DInSAR) is an EO technique that utilizes spacebourne synthetic aperture radar (SAR) data to measure millimetric rates of ground deformation from the differences in phase between image acquisitions. However, two significant limitations of DInSAR analysis are that incoherence restricts measurements to urbanised or rocky areas and free, readily available data with sufficient temporal coverage has not historically been available. In this regard, the Intermittent Small Baseline Subset (ISBAS) is a processing algorithm which is capable of computing velocities over land cover types that have typically been unfavourable for DInSAR analysis. In addition, as part of the Copernicus EO program, the Sentinel-1 satellite provides readily available conflict-free data every 6 days in Europe. The purpose of this research is to demonstrate the potential of the ISBAS processing method and Sentinel-1 SAR data for enhanced capability to monitor ground movements related to geological hazards. Previously, the initial results utilizing the ISBAS method on archive data have identified notable deformations over former coalfields in the UK. Here, previous research was revisited over the Northumberland and Durham coalfield, whereby the ISBAS method was applied to archive and Sentinel-1 data providing deformation data spanning 3 decades. The results show that unexpected and changing amounts of ground motion can be present over former coalfields. The near complete coverage of measurements aided the interpretation and most notably temporal correlations between the rise of mine water and surface heave were made. The results showed that ISBAS measurements had the potential to be utilized to map changes in groundwater levels. Subsequently, an analytical model based upon the principle of effective stress and concept of mine water ponds was developed to relate changes in groundwater levels to changes in the thickness of the strata and, hence, determine surface movement. The forward models estimate surface heave utilising measurements from monitoring boreholes. The models were calibrated and validated using ISBAS measurements, where good agreement was found between the model and the DInSAR, over the demonstration site of the Nottinghamshire coalfields. The ISBAS measurements were then inverted to estimate the change in groundwater levels across the whole coalfield, providing greater spatial coverage than could be inferred from the spatially sparse monitoring boreholes or the forward model. The inverse map was then utilized to predict the time it will take for groundwater to discharge out of the Coal Measures rock. Additionally, the seamless coverage and regular revisit of Sentinel-1 affords the potential for wide-area monitoring of mining deformations and other geohazards. This was demonstrated over the Netherlands where multiple stacks of data were processed and mosaicked together to produce a wide-area-map. The motions, attributed to compressible soils, infrastructure settlement, peat oxidation, gas production, salt mining and underground and opencast mining, were validated with all available independent ancillary information such as previous persistent scatterer interferometry (PSI) deformation maps, models of subsidence and settlement susceptibility and GPS measurements. A statistical analysis showed that measurements in rural areas can provide reliable information with a high degree of confidence (5σ). Finally, the processing requirements for a full Europe-wide deformation map were calculated to determine the opportunity and challenges Sentinel-1 presents for future operational services.

Deformation bands are the primary structural element of fault damage zones within porous granular rocks. They are sub-seismic structures that act to modify the petrophysical properties of the host lithology, and as such are an area of focused research to understand their impact on fluid flow in subsurface reservoirs. Deformation bands have been shown to negatively impact fluid flow in reservoirs, with reduced porosity and permeability, and therefore pose a problem for many subsurface energy resources including hydrocarbon exploration and production, groundwater aquifer management, geothermal energies, and carbon sequestration. Deformation bands require a diverse methodological approach in order to fully understand the mechanisms of their formation and their impacts on rock properties. Current understanding of deformation bands has been drawn primarily from field outcrops, subsurface sampling, as well as insights provided by experimental rock mechanics. It is suggested that the formation of these structures and their properties is strongly related to host lithological properties, such as porosity, grain size, sorting and mineralogy, as well as the stress conditions at which they form. Their prevalence within high porosity, coarse-grained lithologies of aeolian origin has shown that grain size and porosity are the primary controls on their formation. However, the prevalence of this facies in the literature presents sampling bias and therefore bias in interpretation of the controls on their formation, with other lithological variables such as grain sorting and bed thickness, relatively understudied. This thesis presents results of an integrated approach to understand the controls on deformation band formation, and the controls on their petrophysical properties. Mixed aeolian-fluvial reservoirs of the United Kingdom, the Triassic Sherwood Sandstone Group and the Devonian Old Red Sandstone Group are host to pervasive deformation band networks associated with faulting, and also offer the unique opportunity to examine the role of extreme lithological variability on their formation. Field sampling of fault damage zones and deformation bands is combined with petrographic and microstructural analysis and complemented with experimental rock mechanics to investigate the link between sedimentary facies and deformation band formation and petrophysical impact. Results of petrographic and microstructural analysis show that the type of deformation band structure formed is function of the porosity and grain size of the host lithology. Grain size distribution analysis reveals fractal grain size relationships which reflect the deformation mechanisms of band formation that is strongly influenced by grain sorting. Deformation bands within aeolian lithofacies display higher porosity and cataclasis than those within fluvial lithofacies, resulting in greater reduction in permeability. This field observation is also supported by triaxial deformation experiments on unconsolidated quartz aggregates in which the porosity, grain size, and mineralogy remain fixed, and sorting is varied. Sorting is found to influence the micromechanics of deformation, and thus the grain textures produced by cataclasis, resulting in greater permeability reduction within well-sorted materials. Measurements of deformation band intensity using two dimensional window sampling also reveal a strong influence of grain sorting on both the intensity of fault damage zones, and the width of deformation bands. Intensity is highest within well-sorted lithologies, where permeability reduction is also highest, however, the average width and width variability of deformation bands is greatest within fluvial facies. It may be proposed that the increased intensity of bands within aeolian facies, may be balanced by the increased width within fluvial facies, and therefore these structures may act to maintain any inherent fluid flow heterogeneity. These observations provide crucial insight into the effects of facies and ultimately lithological properties on deformation bands in mixed aeolian-fluvial reservoirs.

This thesis helps determine some key structural and geodynamic controls on the evolution of Carboniferous basins in northern England and Scotland. One key control on early Carboniferous (rift) basin evolution in northern England is the role of buoyant and pre-existing granite intrusions in causing localised basement highs. To investigate this relationship, lithosphere-scale numerical modelling and sedimentological approaches are combined. Whereas rift basins are typically considered to be largely normal fault driven systems, lithosphere-scale numerical modelling of the Pennine Basin highlights the role of flexural isostasy in determining basin geometry. Sedimentological-based studies of the Fell Sandstone Formation show that aspects of the basin fill do not conform well with classically depicted models for the region. Highlighted divergences from these models relate to occurrences of granite-cored basement domes or monoclines, whose origins as basement highs are associated with buoyancy and flexural isostatic processes. Local seismic and borehole-based mapping of the late Carboniferous succession in the Canonbie Coalfield and in the Midland Valley of Scotland provides evidence of repeated episodes of positive inversion and unconformities. Three phases of accelerated intra-basin deformation are identified: during the middle-late Namurian, the Duckmantian-Bolsovian, and Asturian-Stephanian. Regional depositional and subsidence trends and more local depositional and structural trends help inform an original structural and geodynamic model for the late Carboniferous basins of the British Isles. It is suggested that northern England and Scotland formed part of an extensive 'broken' Variscan foreland system during late Carboniferous times. The regional structural and geodynamic frameworks for the Carboniferous succession of northern England and Scotland presented in this thesis could be used in combination with other tools, such as the regional subsurface temperature modelling methodology presented, to aid deep geothermal exploration and offshore petroleum exploration. More importantly, they may help reinvigorate research into these rocks.

Oceanic transform faults are considered relatively weak structures and are dominantly aseismic, but occasionally host larger earthquakes (Mw >6.0) that occur quasiperiodically. The seismic behaviour varies along-strike, down-dip and between different oceanic transforms. Several mechanisms have been proposed to explain this mechanical weakness and observed variability in seismic behaviour. These include: (1) hydration and alteration of mafic and ultramafic minerals to frictionally weaker phases; (2) elevated fluid pressure; (3) fluid-driven weakening mechanisms and strain localisation and (4) spatial variation in fault zone damage and mechanical properties. There is, however, limited direct geological evidence on the mechanical properties of creeping and locked portions of oceanic transforms. This thesis investigates the geological controls on the seismic behaviour and strength of oceanic transforms using the exhumed Southern Troodos Transform Fault Zone (STTFZ) in Cyprus as an analogue for active oceanic transforms. Deformation in the STTFZ took place within the thermally-defined seismogenic zone (T < 600◦C). Within serpentinite shear zones, ubiquitous fractures and macroscopically ductile serpentinite fabrics are mutually cross-cutting. These serpentinite fabrics developed progressively from lizardite-rich mesh-textured serpentinite to intensely-foliated, chrysotile-rich phyllonitic serpentinite with increased strain. Dissolution-precipitation is considered an important fabric-forming mechanism during this transition. Within the mafic crust, jointed dolerite dykes were progressively deformed to generate fault breccias and chlorite-rich fault zones, and brittle fracture and gouge formation were important deformation processes. Direct-shear friction experiments on natural samples show that chlorite-rich faults are weak (µ < 0.3) and velocity-strengthening, while less deformed dolerite crust is strong (µ ∼0.7) and velocity-weakening. The geological data indicate that variable deformation and alteration can control the weakness and seismic style of oceanic transforms. In this model, foliated serpentinites and chlorite-rich fault gouges represent weak and dominantly creeping portions. In contrast, less deformed and altered sections remain strong and represent locked patches where earthquakes may nucleate.

Climate change poses a significant risk to water supply resilience. Reduced summer rainfall combined with elevated temperatures are likely to threaten both water quantity and water quality. With respect to water quality, shallow warmer reservoirs can increase risk of biological causes of poor quality, for example due to harmful algal blooms, cyanobacteria toxins and taste and odour metabolites. This was investigated at Llandegfedd, the largest potable water reservoir and a critical water supply system in Wales. The overarching aim addressed in this thesis was to determine if the reservoir would be vulnerable to poor water quality events in the future. To this end, the project comprised four main areas of research: 1. Historical data; 2. Water nutrient dynamics; 3. Sediment nutrient dynamics; 4. Effects of extreme weather events upon water quality. Analysis of water samples indicated phosphorus limitation and the reservoir overall was classified as oligotrophic; unusual for a lowland reservoir. Mass balance analysis demonstrated low internal loading potential even in summer months, which was supported by sediment phosphorus measurements. Allochthonous sources of phosphorus were responsible for the low levels of bioavailable P in the water column. In contrast, the shallowest site at the northern end of the reservoir, adjacent to the main pumped inflow, was eutrophic and at highest risk of water quality deterioration, cyanobacterial growth and geosmin production. Analysis of extreme weather events indicated this risk to be compounded by pulse rainfall events. The reservoir relied upon an allochthonous source of phosphorous, with the refilling process also changing nutrient dynamics through increasing phosphorous concentrations. An additional finding of this study was that analysis of nutrients pre and post water abstraction tower failure around 1999/2000 indicated that the current water abstraction method is inappropriate for monitoring water quality risk at this site, demonstrating the need for enhanced monitoring. This study has shown that Llandegfedd Reservoir remains oligotrophic despite potential for internal P loading, suggesting possible future issues with water quality at the site. This is compounded by extreme weather events and patterns of drawdown and refilling. This is an important warning to the wider Water Industry that oligotrophic water supply reservoirs still require significant monitoring to assess water supply resilience in the face of climate change.

Ancient dryland continental basins commonly comprise sedimentary fill that records the activity of both fluvial and aeolian environments. Despite extensive studies of dryland ephemeral fluvial systems, detailed three dimensional facies models for these systems are appreciably fewer in number and are less developed compared to those of their meandering and braided fluvial counterparts. This is despite the fact that depositional models illustrate the arrangement and interactions between depositional elements, along with the vertical and lateral connectivity of those elements, which are particularly useful and important for reservoir characterisation. This work focusses on an extensive outcrop analogue study of the dryland fluvial Kayenta Formation of the Colorado Plateau, USA, and applies the findings to a detailed core study of the Leman Sandstone, a similar depositional setting within the subsurface of the Southern North Sea, UK. The work utilises extensive regional fieldwork to examine the sedimentology, geometries, and interactions of ephemeral fluvial and aeolian environments, along with analysis of the spatial and temporal variations across the depositional system. Results show that the Kayenta ephemeral fluvial system is dominated by sandy laterally and vertically amalgamated, poorly channelised to sheet-like elements, with abundant upper flow regime structures. Spatial analysis of the system indicates many trends that are similar to those of a dryland terminal fluvial system, whereas temporal analysis indicates an overall regression of the fluvial system through time. This study provides valuable sedimentological data for characterising dryland fluvial systems, particularly when analysing the spatial and temporal variations of the system and demonstrates the inherent complexity in dryland fluvial systems and the downstream architectural and compositional relationships that they depict. These results are used to reconstruct the Leman Sandstone, providing valuable three dimensional data, in order to better characterise basin scale migration and reservoir quality.

The Aeolian arc is characterised by its complex geodynamic setting, with a heterogeneous mantle source and differing extents of shallow-level magmatic processes. These processes result in large within arc geochemical variations influencing the magma compositions erupted and styles of volcanism in the region distinguishing it from other volcanic arcs worldwide. Intermediate to silicic volcanism dominates during the most recent eruption stages in the central Aeolian arc, on Vulcano, Lipari and Salina after the first occurrence of rhyolitic volcanism in the Aeolian archipelago. Key eruptive centres from the central Aeolian arc characterised by alternating periods of Vulcanian to Subplinian explosive events and lava flow effusion were selected as case studies including La Fossa di Vulcano and the Lentia domes on Vulcano, the southern dome field and northern rhyolitic centres on Lipari and the Pollara crater on Salina. This study quantitatively assesses the role of crustal contamination in the generation of intermediate and silicic magmas in the central Aeolian arc, geochemically and isotopically constrains the evolution of the La Fossa di Vulcano magmatic system and identifies the shallow conduit processes during the 1888-90 eruption of La Fossa di Vulcano. We present a stratigraphically controlled dataset to elucidate magma storage conditions, magmatic processes occurring at different levels in the subvolcanic system, and the role and extent of crustal assimilation in producing intermediate to felsic magmas since the switch to dominantly rhyolitic volcanism in the central Aeolian arc. New major- and trace-element geochemistry, stable- and radiogenic isotope geochemistry data from characteristic crustal xenoliths from the different levels within the Calabro Peloritano basement are presented to quantify the role of crustal contamination during magmatic evolution in the central Aeolian arc. This study of the central Aeolian arc quantitatively assesses the role of source and crustal contamination at arguably the most hazardous volcanoes in Aeolian arc.

In the Philippines, aquaculture in freshwater lakes contributes significantly to its economy, food security and employment. However, intensive aquaculture often leads to degradation in lake ecosystem integrity because of nutrient fertilisation resulting in harmful algal blooms (HABs), eutrophication and degradation of water quality. The few limnological and palaeolimnological studies carried out on Philippine lakes demonstrate a link between aquaculture activity and degraded water quality but there is a lack of information to help define how lakes have reacted over time to changing intensities of aquaculture and other catchment effects. This research attempts to redress this imbalance by using two different palaeolimnological approaches to assess the impact of aquaculture on six of the Seven Lakes of San Pablo (Luzon Island). Both approaches used multiple proxies, specifically, chlorophyll and carotenoid pigments, carbon and nitrogen isotopes (δ13C, δ15N) and C/N ratios to help disentangle lake-specific effects of aquaculture from the impacts of regional drivers. The first approach used generalised additive models (GAMs) to assess responses of lakes along an aquaculture disturbance gradient and hence whether lake response was proportional to the level of aquaculture. The second approach endeavoured to quantify the extent to which aquaculture (and other drivers) led to change in algal communities using variance partitioning analysis. Using this whole-ecosystem "experimental design" across individual lakes allowed for a more critical interpretation of the pigment and isotopic records. Both approaches concluded that there was no proportional relationship between changes in the proxy record and level of aquaculture disturbance, suggesting aquaculture is not the main driver of change. Land use changes (since 1950) explained the greatest proportion of variance and corresponded to periods of significant temporal change indicating it was a more dominant driver of change in algal communities. As aquaculture intensity increased, lakes became more eutrophic and anoxia increased due to nutrient enrichment from a combination of anthropogenic (urbanisation, coconut plantations and aquaculture) and climatic factors. In the majority of the lakes, changes in the proxy records predate the introduction of aquaculture, providing evidence that aquaculture exacerbated pre-existing change especially in the lakes with the highest aquaculture disturbance. Furthermore, each lake had a distinctive response to aquaculture due to the impact of multiple stressors (climate, land use and aquaculture) especially on the high disturbance lakes, and the modification by individual lake characteristics such as hydro-morphology. Mitigation strategies, therefore, need to be specifically developed for each lake, with consideration given to their distinct morphological features and how this influences their complex response to aquaculture and other environmental pressures.

Along plate interfaces in subduction zones, displacement occurs by a spectrum of slip styles, including ∼steady creep, slow-slip events, tectonic tremor, and earthquakes. However, the factors which determine where, and how, different slip styles occur, are not clear. In Japan, on Kyushu, three exposures of plate boundary shear zones, exhumed from different metamorphic conditions along a similar paleo-margin, within the temperature range 300-550 ◦C, represent a natural laboratory to understand processes which influence slip style along the subduction plate interface. In exposures exhumed from conditions corresponding to localised metamorphic dehydration reactions, foliations and quartz veins are mutually overprinting, indicating episodic brittle behaviour within an otherwise viscous regime. Local fluid pressurisation, and amplified shear stresses along lithological contacts, are inferred to drive embrittlement. A quartz recrystallised grain size piezometer is applied to viscously deformed quartz veins, and used to constrain the level of differential stress within hydrated metabasalt. Results suggest that hydrated oceanic crust is far weaker than dry crust, and weak enough to control plate interface rheology. Microstructural observations of antigorite serpentinite deformed at ∼ 500 ◦C suggest that foliation development results in a reduction in viscosity. Geometric relationships within the shear zone deformed at ∼ 500 ◦C suggest that serpentinite may be more viscous than hydrated oceanic crust and subducted sediment, and therefore plate interface strain may be concentrated in the subducting plate, along the slab-mantle boundary. Outcrop and microstructural observations suggest that, within the plate boundary shear zone, subducted sediments are slightly weaker than hydrated oceanic crust, and antigorite serpentinite is stronger than both subducted sediments and hydrated oceanic crust. Overall, brittle instabilities occur in all of the deformed lithologies due to a combination of metamorphic dehydration reactions locally reducing effective stresses, and local shear stress amplifications along lithological contacts.

The Tara Deep Zn-Pb deposit (currently 26.2 Mt @ 8.4% Zn, 1.6% Pb) is the latest major discovery by Boliden Tara Mines (first announced in 2016) which significantly adds to the existing world-class Navan deposit. Located 2 km south of the Navan deposit in Co. Meath, Ireland, economic mineralization is hosted by upper Tournaisian carbonates (Pale Beds; 87% of the total economic resource), within a degraded footwall of a major south-dipping normal fault, and also within lower Viséan sedimentary breccias (S Fault Conglomerates; 13% of the total economic resource). Sphalerite and galena are the dominant sulfides, with massive, cavity fill and brecciated textures dominating. These textures attest complex, subsurface, episodic mineralization events that display considerable reworking, fracturing, dolomitization, open-space infill and selective replacement. Lower Viséan syn-rift sliding, erosion, and deposition of thick debrites and calc-turbidites at Tara Deep record basin margin processes near extensional faulting associated with formation of the Dublin Basin. These sedimentary breccias host detrital sulfide-rich clasts and offer unambiguous evidence that the onset of mineralization occurred during the upper Tournaisian. Conventionally drilled 34S values of base metal sulfides have a bimodal distribution suggesting both bacteriogenic (-13.5 to -3.6 ‰) and hydrothermal sulfur sources (+3.4 to +16.2 ‰). Both textural and sulfur isotope data reveal the dynamic nature of mineralization at Tara Deep and infer fluid mixing. Conventional lead isotope analyses display remarkably homogenous 206Pb/204Pb of 18.23±0.006 (2σ, n=25), which is consistent with Pb isotope data across the Navan deposit. Subsequently, Tara Deep and Navan are isotopically similar, showing both a statistically identical Pb isotopic signature and a bimodal sulfide S isotopic distribution and homogeneous sulfate signature. In particular, the Pb isotopes and the hydrothermal S signature, correlate with Navan and agree that base metals were leached from the underlying Lower Palaeozoic basement, this suggests that similar deep, circulating metalliferous fluids were also involved at Tara Deep. However, despite these similarities, key differences can be recognized within the S isotope data; around 5‰ shifts to higher 34S in the surface-derived S isotope signatures (both bacteriogenic sulfide and sulfate) indicate that Tara Deep's sulfur was sourced from a distinct seawater/connate fluid signature. Floatation concentrate samples were obtained on representative drillholes from across the Tara Deep deposit by Boliden Tara Mines' laboratory to inform recovery data for future financial modelling. The concentrates produced were analysed for S and Pb isotopes. The samples reveal limited variation with mean δ34S = -6 ± 5.9 ‰ (n = 38), and galena concentrate mean 206Pb/204Pb=18.22 ± 0.004 (n = 19). Mass balance calculations suggest that ~90 percent of the Tara Deep sulfides were derived from bacteriogenic reduction of contemporaneous Lower Carboniferous seawater sulfate. In contrast, metals were acquired from a local, orogenic crustal source beneath the orebody. These concentrate isotopic signatures differ from those associated with the Main Navan Orebody, in particular the bacteriogenic mode, reiterating that Tara Deep should be considered as an isolated deposit in space, and potentially time, and not an allochthonous block of the Navan deposit. As was reported for the world-class Navan deposit, enhanced bacterial activity was fundamental to ore deposition at Tara Deep, providing significant reassurance for continuing exploration. Tara Deep is located at depths of between 1.2-1.9 km within fault-controlled terraces on the degraded footwall of a major normal fault system. The system formed as a result of a rapidly subsiding basin margin during the upper Tournaisian extension. The region's long lived and dynamic evolution has resulted in a complex architecture of large normal and strike slip faults. The complexity of the Dublin Basin margin evolution at Navan can be divided into three distinct phases: pre-rift ramp sedimentation in the Lower Carboniferous (Mississippian), syn-rift abrupt detachment and destructive debris flows in the lower Viséan, and finally late-rift basin infill during the Viséan. Diagenetic processes include dolomitization, mineralization and extensive pressure solution, which complicate the lithofacies reconstruction by occluding pre-existing textures. Dolomitization occurs in four phases: D1 - D4. D1 predates mineralization and represents early replacement by non-ferroan euhedral dolomite (30 μm), this dolomite typically has cloudy cores (often associated with Mn), with clear ferrous rims. D2 represents interparticle infill by anhedral (50 μm) ferroan dolomite. D3 occurs as late, coarse, non-ferroan saddle dolomite cement which occurs in vugs. D4 occurs as the last phase throughout the Tara Deep succession, is nanocrystalline, and is related to burial dolomitization witnessed by its close association with pressure solution seams. Pressure solution is extensive at Tara Deep and is partially responsible for the generation of common and distinct stylo-nodular textures in the Pale Beds, and can also lead to occlusion of the original host rock fabric in the Thin Bedded Unit. Oxygen and carbon isotopes are used to constrain these interpretations. Mineralization is also intimately linked to basin margin development and architecture and is recorded across early syn-rifting textures to late-rifting textures, highlighting the complexity and longevity of the mineralizing system within the Lower Carboniferous (Mississippian) carbonates. Together these processes speak of a dynamic sedimentary, tectonic, and microbiological environment which has culminated in an exceptional accumulation and preservation of base metals during the Lower Carboniferous. Mineralization initiated during an early phase of the developing Dublin Basin (syn-diagenetically) and kept pace with rifting and subsequently an evolving basin. The Tara Deep deposit has many similarities with the neighbouring Navan deposit reflecting comparable controls on the mineralizing processes in terms of host rocks, Pb and S sources, and tectonic environment.

The Canadian Prairies rely heavily on ample amounts of freshwater, especially for their agricultural activities. Its position in the rain shadow of the Rocky Mountains and long-distance to major water bodies makes this area prone to re-occurring droughts and occasional floods. Especially the former creates costly natural and socio-economic disasters. Although, our understanding of climate drivers is fairly robust on a global scale, it is incredibly limited on a regional scale, which is indicated by our inability to fully explain the 2000s drought in the Canadian Prairie. Long-term regional droughts have the potential to occur abruptly but there is low confidence in current climate projections of their frequency, severity and timing (IPCC AR5, 2013). This uncertainty is to a large part caused by our limited understanding of climate drivers on regional and sub-centennial spatio-temporal scales. Here, the exceptionally low density of robust, (cross-) validated palaeoclimate records in the Northern Great Plains is particularly problematic. Dendrohydrological reconstructions are sparse, mostly short (<500 years) and of reduced fidelity in this region. Diatom-inferred salinity is based on the premise that water balance (P-ET) in a closed lake is traced by salinity but several in-lake processes exist that can decouple the salinity - water balance relationship. Pollen-inferred temperature/precipitation uses the vegetation's response to climate variability which limits its temporal resolution to 50-100 years. Moreover, training data sets in the Northern Great Plains that are used to find modern analogues are affected by anthropogenic impact on species distribution. The meta-problem for the Canadian Prairies hence is two-fold: we lack a) proxies that allow high spatio-temporal resolution and b) robust, site-validated palaeoclimate reconstructions of multi-millenial length. In this thesis, we substantially contribute to the understanding of the climate system in the Canadian Prairies and how novel proxies in terrestrial palaeoclimatology can offer us valuable insights into past climate variability. We advance comparatively novel proxies (in terrestrial palaeoclimatology) based on long-chain diols, ostracod trace metal geochemistry, X-Ray Fluorescence (XRF) and compound-specific isotope analysis (CSIA). Moreover, we apply long-chain alkenones, CSIA, n-alkanes, pigments, bulk isotope analysis (13C), XRF and grain size analysis to reconstruct past lake surface temperature, hydrology and organic matter composition. In the process, we use cutting-edge technology like Mass Spectrometry Imaging to gain sub-annual insights into temperature variability during the abrupt termination of the Holocene Climatic Optimum. Our ability to understand climate events, their causes and for the recent events (e.g. Dust Bowl Drought) our role in it, can be the cradle of desperately needed changes in how we manage the earth system. Climate reconstructions as the basis for projections offer a glimpse into a potential future and at the same time incentive to avoid that future.

Lava-like and welded pyroclastic deposits are commonly associated with vent-proximal, high-temperature explosive eruptions, and due to the nature of welding of these deposits, evidence of the depositional and sedimentological aspect of the deposit is often absent. As a result, the dynamics and mechanisms of deposition and welding processes in high-temperature eruptions are poorly understood and this has often led to the misinterpretation of such welded deposits. This limited understanding can lead to misleading interpretations and underestimations of the potential hazards associated with active volcanic environments. This project is an investigation into the behaviour and emplacement of the welded and lava-like deposits belonging to the Ucanca and Guajara Formations of the southern flank of the Las Cañadas Caldera, Tenerife. Six individual eruptive packages are described and documented, representing explosive, destructive and constructive stages of the Ucanca and Guajara caldera-forming episodes. A systematic field campaign involving mapping and detailed stratigraphic logging of the deposits, combined with methodological sampling for petrographic, geochemical and thermal analysis, together with determination of the rocks' physical properties, has established the emplacement dynamics of the units, as well as geochemical and welding variations throughout individual units and across the proposed members. The description and analysis of welding textures at different scales allowed for sensitive mapping of welding intensity, providing insights into the controls and depositional factors contributing to the deformation of pyroclasts, both syn- and post-emplacement. Together these data provide the first detailed robust interpretation of the Ucanca and Guajara deposits, a key stage in the volcanic evolution of Tenerife. Extensive evidence is presented in support of their interpretation as deposits from a series of extremely high-grade pyroclastic density currents (PDCs). A variety of novel and exciting welding textures are documented, providing insight into the emplacement dynamics, thermal histories, and constraints on welding such as current interaction with variable lithic input. This work proposes a new classification system for high-grade ignimbrites, which are overly simplified and omitted in existing schemes, and may be applied to deposits in other volcanic settings.

Coalbed methane (CBM) is an important energy source in many countries. The origin and post-generation evolution of methane in coalbeds are rather poorly understood despite the importance of assessment of reserves and developing exploration strategies. Stable isotopes are the typical geochemical tools to analyse the gas origin and subsequent evolution. Noble gases are widely used for identifying the source of fluids in reservoirs and the impact of the tectonic and hydrologic activities on hydrocarbon generation and preservation. In this PhD, I have studied the composition of gases from the Southeast Qinshui Basin, the most CBM productive region in China, and the Liupanshui Coalfield, a CBM development target in southern China. Methane in these two regions was formed in the late Triassic during burial and heating driven by magmatic activity in the Late Jurassic to Early Cretaceous. Cenozoic basin inversion brought the coals to a shallow depth. This study aims to establish how the gas formed, to estimate the contribution of magmatic heating on methane generation and the influence of basin exhumation on gas storage. Nineteen gas samples were taken in April 2017 from methane-producing wellheads along an E-W transect perpendicular to the boundary fault in Southeast Qinshui Basin (SQB) in northern China. The stable isotope compositions (δ13C= -35.2 to -30.2‰, δD= -194 to -155‰) indicates a thermogenic origin with limited microbial input. They are, however, lighter than expected based on coal maturity, perhaps due to adsorption/desorption fractionation during commercial gas extraction. He-Ne-Ar isotopes are a mixture of crustal-radiogenic gas with air-derived noble gases from groundwater. 4He concentrations (0.52 to 33.25 ppmv) and 4He/40Ar* ratios (0.06-1.74) are unusually low. He-Ne-Ar concentrations are consistent with the open system Rayleigh fractionation of noble gases derived from air-saturated water (ASW) with 4He/40Ar*=1 during gas extraction. The low 4He/40Ar* compared with average crust (5) or local production (13) values, implies that radiogenic 4He produced in the coals was lost prior to equilibrium between gas and water phase in the reservoir. This likely occurred during rapid exhumation in Cenozoic. The event may have led to the loss of up to 44% of the methane from the coal seams. The depletion of Xe and Kr without significant enrichment of Ne suggests the strong retention of Kr and Xe in SQB coals. Ten CBM samples were collected in April 2018 from the four blocks containing different mature coals in Liupanshui Coalfield (LPC) in southern China. Two gas samples were collected from the same two wells in the Dahebian block in October 2018. This is the first gas geochemical work in LPC. Methane is mainly thermogenic in origin based on the C1/(C2+C3) ratio (16-971), δ13CCH4 (-42.9 to -34.9‰) and δDCH4 (-206 to -140‰). The difference in major gas and stable isotope compositions between the four blocks of LPC is mainly due to the different extent of maturation of coals in each block. Noble gases in LPC are a mixture of air-derived gases from ASW with crustal gases in the reservoir. The lower proportion of nucleogenic Ne and 4He/40Ar* ratios in gases from Qingshan block compared with other blocks implies an evident He and Ne loss. The gas loss is also inferred to be the result of basin inversion. 20Ne/36Ar ratios (0.23-0.70) are higher than local ASW (0.16), requiring a re-dissolution fractionation process similar to that proposed for CO2 gas reservoirs (Gilfillan et al., 2008). 84Kr/36Ar and 132Xe/36Ar ratios in LPC are mostly higher than the modelled fractionation lines. This is explained by desorption of initial trapped Xe and Kr in the coal matrix. The Qingshan block gases contain the same depleted Kr and Xe pattern as SQB, suggesting the stronger adsorption capacity of local coals to Kr and Xe. Over 93% of He and 9% of Ar budget of the coal basins is estimated to have been lost during the gas loss process. It explains the absence of mantle volatiles in the SQB and LPC CBM. This demonstrates the importance of basin inversion on gas preservation in shallow CBM and shows that the light noble gases are essential for tracing such a process.

The recoverable proportion of known mobile resources from fluvial multi-storey sandbodies (MSBs) reservoirs is relatively low. The low recovery proportion can be attributed to a lack of a three-dimensional understanding of the reservoir architecture, a lack of consideration of meso-scale heterogeneity, and a lack of geological realism within reservoir models. This thesis considers the architectural nature of unconfined and confined MSBs. The work will: 1) develop an understanding of the main controls upon preservation and deposition of architectural elements within unconfined and confined MSBs and determine key diagnostic features attributed to them. Finally, this work will determine best-practice stochastic reservoir modelling practices for the simulation of unconfined and confined MSBs. The works presented here use terrestrial photogrammetry, sedimentary logging and palaeohydrodynamic reconstructions from unconfined and confined multi-storey sandbodies to determine key architectural diagnostic criteria. Multi-point statistics, object-based models and sequential indicator simulation are used to determine the most appropriate algorithm to represent the two systems. Results indicate that unconfined MSBs show complex barform architectures with compound bar formation. This is highlighted by the presence of upstream accretion elements, developed by variable discharge. In confined MSBs large water depths relative to sediment supply indicate that local accommodation is not being filled and that compound bar formation and upstream accretion elements are impeded. It is therefore proposed that unconfined MSBs can be identified by the presense of complex barform geometries and upstream accretion elements, whereas confined MSBs, due to their larger water depths can be identified by the lack of upstream accretion elements and a lack of correlation between maximum flow depth reconstructions and the thickness of bars. Reservoir model tests suggest that the best method of representing these systems is through the use of three-dimensional multi-point statistics simulations, which provide the most realistic statistical and visual representation of the fluvial environment.

The Panama Arc formed following subduction initiation along the southwestern margin of the Caribbean Oceanic Plateau in the Late Cretaceous. Evidence for the arc initiation upon the oceanic plateau basement is preserved in uplifted segments of the forearc basement across southern Central America. Despite subduction initiation being one of the most significant processes of the plate tectonic cycle, it remains the most poorly understood, and the unique geological record of Panama and nearby Costa Rica and Colombia provides a valuable opportunity to investigate magmatic and tectonic processes in a nascent subduction zone. This study uses field observations, biostratigraphic dating, whole-rock geochemistry and Nd isotope geochemistry to investigate the nature of the plateau basement and the first magmatic products of subduction initiation across a ca. 650 km transect from western Panama to northwest Colombia. New results reveal that the oceanic plateau across this region is lithostratigraphically and geochemically heterogeneous. Similar to the bulk of the Caribbean Oceanic Plateau, the studied plateau sequences were sourced from a heterogeneous mantle plume likely associated with the initiation of the Galapagos hotspot in the Late Cretaceous. Earlier magmatic phases of the oceanic plateau in Panama and nearby Colombia are possible, but remain poorly documented in the studied area. In addition, this study provides a new insight into subduction initiation along the oceanic plateau with the recognition of two compositionally distinct 'proto-arc' groups. An early proto-arc magmatic phase includes sequences of pillow basalts, basaltic dykes and gabbroic intrusions that were formed from a plume-like source and are geochemically transitional between plateau and mature arc sequences. The second proto-arc phase is represented by basaltic dykes, locally crosscutting plateau and early proto-arc sequences, which have more depleted geochemical signature, and were produced from a MORB-like source with variable slab input. These proto-arc groups are separated from the plateau by a regional limestone formation that indicates cessation of plateau magmatism ca. 5-10 Myr prior to subduction initiation in the Campanian (ca. 72-73 Ma). Existing geochronological data and new results indicate that the establishment of a mature arc from the onset of supra-subduction magmatism took less than ca. 4 Myr. Overall, this study shows that igneous complexes of Panama and Colombia represent a novel record of subduction initiation which does not follow previous models of plume induced subduction initiation in Central America or spontaneous subduction initiation along the Izu-Bonin-Mariana Arc system. New and previous regional constraints suggest instead ii that subduction initiation in Panama most likely occurred due to propagation of an east- to north-facing subduction zone along the southern margin of the oceanic plateau during its collision with the South American continent.

The petrogenesis of intermediate silica magmas in continental arc settings remains heavily debated. Contention focuses on the importance of slab components (subducted sediments and altered oceanic crust) compared to processes within the overlying plate to imparting the distinctive geochemical signature of intermediate arc lavas. The Colombian Andes are an understudied region compared to other continental arc settings. The region has several compelling features, including a moderate crustal thickness for continental arcs and geochemically well characterised mid and lower crustal basement. This study utilises high quality geochemistry of major and trace elements and isotopes as petrogenetic tracers of the different components and processes within the Colombian Volcanic Arc, demonstrating that mantle derived melts undergo magma mixing and assimilation processes during ascent through the crust, promoting a diversity of geochemical signatures mainly dependent on pathway through the crust and assimilation of specific crustal components. A developing idea is that crustal thickness may act as a control on some arc parameters, and it is clear that magmatism is strongly controlled by crustal features from previous orogenic events, allowing for primitive compositions to be emplaced in contrast to highly fractionated compositions.

During the Eocene-Oligocene Transition (EOT; ~34.4-33.7 Ma), the Earth experienced a major shift in climate state, from so called "greenhouse" to "icehouse" conditions, with the first formation of the modern continental-scale ice sheet on Antarctica (Oi-1 event: ~33.7 Ma). This transition was associated with deep-sea cooling, glacioeustatic sea level fall, worldwide regressions, along with major disturbances in the global carbon cycle and ecosystems. To investigate this climatic disruption, high- resolution coccolith fraction (<20 μm) carbonate stable oxygen (δ18O) and carbon (δ13C) isotope records (~7 ka resolution), palynological and calcareous nannofossil assemblage (~26 ka resolution) records, and bulk sediment X-ray fluorescence analyses (<10 ka resolution) have been generated from a continuously cored (~137 m) and substantially expanded (~4.7 cm ka-1) succession of upper Eocene-lower Oligocene (~4 Ma) mid-shelf marine clays from the central Mississippi, US Gulf Coastal Plain - the Mossy Grove Core (MGC). Based on a refined age-depth model, this multiproxy analysis revealed that the increasing export of nutrients from the Southern Ocean to the tropical and sub-tropical oceans enhanced marine primary production in these regions, further leading to increased sequestration of atmospheric CO2 through an invigorated biological pump. We also found evidence that extraterrestrial impacts may have induced sulfate-aerosol-driven climate forcing, triggering positive feedback mechanisms, and intensifying and/or sustaining the cooling. Further analysis also demonstrated that a significant sea level fall (~34.5 Ma) preceded the Oi-1 event by ~800 ka and represents the first stage of large-scale expansion of the East Antarctica Ice Sheet. This challenges the current view that the dynamics of the EOT are dominated by global cooling during the earliest stages, which then precondition the system to continental-scale ice-sheet expansion in the later stages. We also propose that the earliest stages of the major EOT eustatic sea-level fall had a disproportionate effect on global biogeochemistry, by causing the first major incision of organic- and nutrient-rich coastal low lands that had been accreting under warm, high sea-level greenhouse conditions for tens of millions of years.

Antarctic coastal zones play a key role in regulating global climate, through sea level change, ocean circulation and the global carbon cycle. Observations over recent decades have documented changes such as thinning of ice sheets, freshening of the surrounding ocean and changes in sea ice extent. However, these records are only short and sparse leaving many questions yet to be answered about the drivers of such changes and environmental implications. Palaeoenvironmental records provide the potential to reconstruct such changes over the past and extend observations back through time. This requires a robust understanding of how different proxies work and thus what signal they are recording. This thesis aims to assess the use of two biomarker proxies for reconstructing past environmental conditions in the Antarctic coastal zone, namely compound-specific carbon isotopes of fatty acids and the TEX\(_{86} ^L\) sea surface temperature proxy, as well as applying these and other proxies to reconstruct past environmental conditions. Two marine sediment cores recovered from off the coast of Adélie Land, East Antarctica, are used for this work: a short core spanning roughly the past four centuries, and another core spanning the Holocene. Changes in concentrations and carbon isotopes of two fatty acids in sediment samples are analysed in the short core and compared with down-core changes in other proxy data. Different possible drivers of fatty acid δ13C are explored, of which primary productivity changes appear to be the most likely driver. The C24 fatty acid δ13C is suggested to be predominantly reflecting productivity in open water environments, while C18 fatty acid δ13C is reflecting productivity in the marginal ice zone. Fatty acid δ13C is applied to the Holocene sediment core to reconstruct primary productivity changes. These data suggest that primary productivity was spatially variable over the Holocene. Open water productivity appears to be highest and most stable during the middle and late Holocene periods, after local ice sheets have retreated. Despite a rapid and widespread increase in sea ice concentration in the Late Holocene, open water productivity remains high, possibly reflecting conditions within the Mertz Glacier Polynya, up-wind from the core site. In contrast, ice edge productivity reaches the lowest levels, perhaps due to a shorter ice-free season leading to a lack of stratified, nutrient-rich water. A high-resolution record of TEX86 L from off the coast of Adélie Land, East Antarctica is presented spanning the last four centuries. The TEX86 L record, however, shows no correlation with air temperature in this region over the period of temporal overlap. This, in addition to a consistent over-prediction of temperatures compared to known sea surface temperatures (SST) in the region, and the deviation of glycerol dialkyl glycerol tetraether (GDGT) distributions from the global core top dataset, suggest that TEX86 L is not recording SST. A correlation between TEX86 L and Sand% suggests that TEX86 L is being driven by changes in the strength of the westward coastal currents. We hypothesise that stronger currents are leading to greater advection of GDGTs from further east, where modified Circumpolar Deep Water (MCDW) upwells. MCDW is known to have a greater diversity of archaeal communities and thus, greater advection may lead to greater inputs of GDGTs produced by different archaea, for which the relationship between GDGT cyclisation and temperature may differ. A range of proxies are applied to both sediment cores to reconstruct past changes in different environmental conditions. In the Holocene sediment core, fatty acid hydrogen isotopes indicate a peak in meltwater input during the mid-Holocene which coincides with a widespread increase in sea-ice around the coast, persisting towards the modern day. This is hypothesised to reflect the development of a large ice-shelf cavity in the Ross Sea which fundamentally alters ice-ocean interactions and surface water properties. These surface waters are transported west, enhancing sea ice formation around the coast. This provides a new insight into ice shelf-ocean-sea ice interactions with implications for the incorporation of ice shelves into climate models. Proxy data from the short-core provides a high-resolution insight into the relationship between different environmental factors over the past four centuries. These data highlight the key role of sea ice in driving changes in ice-edge primary productivity, inputs of glacial meltwater and strength of the westward coastal current. Iceedge primary productivity broadly increases when both fast and pack ice are low. Productivity in more open waters, however, appears to be less sensitive to changes in sea ice. Inputs of glacial meltwater also appear to be controlled by sea ice concentrations, perhaps due to isotopically-depleted meltwater being locked up in sea ice and released when extensive melting of sea ice occurs. The strength of the westward current appears to be affected by the concentration of fast ice attached to the coast, due to its effect on wind stress. Comparison with instrumental data is difficult due to the short-term nature of the overlapping datasets. However, there is some indication that wind direction may play a key role in determining sea ice concentrations in this location which, in turn, affects many other environmental conditions offshore Adélie Land.

Observations of radioactivity from beach springs over a period of four decades provides insights into field scale characteristics of a migrating tritium groundwater plume from the oldest UK nuclear site at Sellafield, in Cumbria. The utility of high resolution spatial and decades long temporal tritium coastal discharge data is demonstrated as an indicator tracer of groundwater flows and radionuclide fate to coastal environmental receptors. Data mined from as far back as 1975 is presented to be of historical significance as one of the earliest unpublished radionuclide contaminant plume investigations in the coastal environment. New field data is presented for tritium activity in beach springs and delineates a distinct asymmetric groundwater plume discharge footprint stretching 2600 metres northwards of the site along the foreshore. The spatial distribution of the tritium is further to the north-west than predicted by the Sellafield Ltd conceptual model and extends beyond the perimeter of the current site groundwater monitoring well network. The spatial footprint was further confirmed by additional sample analysis for technetium-99 with similar contributing source areas. The results of the project suggest that the groundwater flow regime to the north-west of the nuclear site is highly complex and narrow plume contaminant contributions are from more than one source, merging and surfacing in low flow beach springs in the intertidal zone. It is recommended that nuclear sites located near the coast should adopt this simple and inexpensive beach spring monitoring practice as a useful spatial and temporal diagnostic tool at the field scale. This method is complimentary to traditional groundwater monitoring wells and has improved far-field conceptualisation of contaminant sources and resultant pathways to the beach springs and concluded low risk levels to the coastal region (as of 2018).

Panama Volcanic Arc (PVA) has a long magmatic history lasting from subduction initiation to the present. Different magmatic phases, e.g. pre-Oligocene arc and Cordillera arc, show different compositions which associate different tectonic settings. To better understand the magmatic and tectonic evolution of PVA, detailed work was conducted in central Panama (from El Valle to the west of Cerro Azul). Whole rock geochemistry shows that the pre-Oligocene Chagres Complex range from basaltic to andesitic while the post-Eocene rocks range from basaltic to rhyolitic. The Chagres complex have similar major elements as those of the post-Eocene mafic rocks but have smaller content of the most incompatible elements, as the former are similar to the oceanic arc basalt and the latter similar to the continental arc basalt. Las Cascadas Formation crystallized from a magma mush similar to the one for the Panama Formation and mineral/glass chemistry further indicate the Las Cascadas Formation magma extracted from the magma mush with or without trapping crystal framework of the mush. Whole rock Sr-Nd-Pb isotopes show that the ambient mantle is the Caribbean Large Igneous Province mantle with HIMU component. Trace element and isotope modelling show that the Chagres Complex have the highest sediment melt and partial melting degree while these parameters are smaller for the Panama Formation. The Cabra/Pedro Miguel Formation have the highest AOC melt and the lowest sediment melt. As the crust thickened through time, the mantle wedge became colder and the melting field in the mantle wedge moved downward and away from the trench, which resulted in the pre-Oligocene arc migrating away from the trench to the post-Eocene arc. The corresponding location of slab fluid/melt releasing also moved downward to a higher pressure due to which slab input decrease from the Chagres Complex to the Panama Formation. The decreasing slab input, probably along with the downward isotherms gave rise to the decreasing partial melting degree. When the Cocos-Nazca spreading centre subducted beneath central Panama, a slab window formed which facilitated AOC melting. Partial melting of ambient mantle metasomatized by this AOC melt formed the Cabra/Pedro Miguel Formation. The olivine basalts have the lowest partial melting degrees which mark the cessation of magmatism in central Panama.

Published datasets of the concentrations of the chalcophile elements in volcanic rocks are rare, and most of our knowledge of their behaviour is based on oceanic arc-like settings, rather than continental arcs, where economically viable deposits of the chalcophiles are generally associated. This thesis, therefore, investigates the processing and distribution of the chalcophile elements within a continental volcanic arc, by presenting novel whole rock analyses of the near complete suite of chalcophile elements in volcanic rock samples collected from several edifices along the Chilean Andes. The data presented demonstrates that continental arc magmas typically achieve saturation in a crystalline sulfide phase early during magmatic evolution, likely at or near the base of the overriding continental crust, prior to ascent and low-pressure fractional crystallisation, and before magnetite fractionation, in contrast to oceanic arc-like settings. Observations are replicated at stratovolcanoes and small eruptive centres. The degree of crystalline sulfide fractionated is modelled to be minimal (≤0.6 wt.%). The thickness of the overriding crust at convergent margins is argued to be the dominant control on the distribution of the chalcophile elements. The implication of these findings is that either secondary processes are required to transport chalcophile elements to the sites of ore deposit formation, or such ore deposits are generated in atypical scenarios (e.g., high magma throughput).

Carbonaceous chondrites are among the most primitive extra-terrestrial materials available for study. These meteorites provide a detailed record of the geological processes and events that have shaped our solar system over the last 4.5 billion years. "Ornans-like" carbonaceous chondrite meteorites, also referred to as CO3 chondrites, comprise pristine, primitive mineralogy that has undergone no or minimal aqueous alteration. CO3 chondrites are also known to contain up to 3.5% carbon in the form of insoluble and soluble organic matter, graphite and carbonates. The CO3 chondrites form a suite of samples that have experienced increasing degrees of thermal metamorphism, from weakly heated CO3.0s such as Colony and DOM 08006, to strongly meta-morphosed CO3.8s such as Isna. Detailed studies of this suite of CO3 chondrites enables firstly a determination of the most primitive and earliest formed aggregates of crystalline, amorphous and organic solids, and their textural relationships from which inferences can be made regarding the nature and composition of the protoplanetary disk; and secondly quantification of the effects of parent body metamorphism on these early solar system solids. In this thesis I have studied 12 CO3 chondrites that cover the whole metamorphic sequence, namely Colony and DOM 08006 (CO3.0), NWA 7892 (CO3.05), MIL 090010 (CO3.1), Kainsaz (CO3.2), Felix (CO3.3), Ornans (CO3.4), Lancé (CO3.5), Moss and ALHA77003 (CO3.6), War-renton (CO3.7) and Isna (CO3.8). Bulk mineralogy and chemical compositions were quantified using X-ray powder diffraction (XRD) and electron probe microanalysis, and were contextualised with in-situ, spatially resolved scanning and transmission electron microscopy (TEM), and synchrotron-based scanning transmission X-ray microscopy (STXM) combined with X-ray ab-sorption near edge structure (XANES) spectroscopy. XRD was used to quantify the bulk modal mineralogy of the CO3 chondrites. I found that the most primitive samples mostly comprise Mg-rich olivine and pyroxene, and Fe-bearing amor-phous silicates. Samples between CO3.0 and CO3.1 contained ~35% forsterite, ~13% Fo60 olivine, ~26% pyroxene, ~2.5 % sulphide, ~0.7 % metal, ~5 % magnetite and ~14 % amorphous material. On heating, forsterite within the primitive samples was systematically replaced by Fe-rich olivine such that all the olivine in the CO3.8 was Fo60. This transformation was linear and could be used for rapidly and accurately defining the petrologic grade of a CO chondrite. The amorphous Febearing silicates were fully crystallised by CO3.2, magnetite had disappeared by CO3.3 and nepheline appeared at CO3.3 and gradually increases in abundance up to CO3.8. Changes in the modal mineralogy are reflected in the bulk chemistry with the matrix becoming depleted in Fe and enriched in Mg, due to equilibration with chondrules, and there is a small linear increase in Cr with increasing metamorphism. Bright-field TEM images show the fine grain size and heterogeneous texture of the matrix in the most primitive CO3 chondrites, which consists of an amorphous groundmass within which is embedded ~ 0.1 μm silicate, sulphide, metal and phyllosilicate grains. TEM imaging also revealed a systematic change in the porosity of the matrix as a function of metamorphic grade. Recrystallization and equilibration of the low porosity, low permeability matrix in the CO3.0-3.1 chondrites caused by metamorphic heating, progressively increased the porosity and average grainsize of the minerals up to CO3.8. Fe L-edge XANES analysis of the STXM data revealed that the amorphous Fe-bearing silicates and the matrix of the most primitive CO3.0 chondrites are almost fully oxidized with the Fe3+/ΣFe ratio close to 1.0. On heating the Fe becomes rapidly reduced with Kainsaz containing only about 10 % Fe3+ and Moss being dominated by Fe2+. Limited spatial variation in the Fe L-edge X-ray absorption spectra was observed in DOM 08006, most likely related to the proximity of metal and sulphides to the amorphous silicates. No significant variation in the Fe L-edge X-ray absorption spectra was observed in the silicate fraction of Moss even down to the 40 nm scale. STXM and XANES at the C, N, and O K-edges reveal spatial variations in the functional chemistry of the organic matter in the most primitive CO3 chondrites. This variation was most evident in the intensity of the aromatic, ketone and carboxyl spectral features. The presence of carbonate was also occasionally observed most particularly in and close to a ~1.3 μm wide carbonate vein in a sample of NWA 7892. As a function of increased metamorphic heating I found that the aromatic group persists while the ketone and carboxyl groups disappear such that in Moss CO3.6 only aromatic carbon was observed (with a potential trace of carbonate). Graphite was not definitively identified in any of the samples. Spectral features on the O K-edge show the progressive crystallisation of the amorphous silicate into olivine with metamorphic heating. The effects of metamorphic heating on the primitive CO3 chondrites is to crystallise the amorphous Fe-bearing silicates, systematically modify the modal mineralogy, increase the porosity of the matrix and homogenise the molecular speciation in the organic matter. Furthermore, the hydrated amorphous silicates dehydrate within a narrow temperature interval of about 100°C and there is a concomitant reduction of the Fe3+ to Fe2+ as the amorphous Fe-silicates transform into crystalline minerals. This reduction of the Fe is facilitated by the changing redox conditions likely due to the removal of oxidizing H2O and the initial presence of reducing agents such as H and C. I conclude that CO meteorites formed from anhydrous parent bodies in which minimal aqueous alteration took place and the main source of water was hydrated amorphous silicates. I propose that these amorphous silicates were hydrated in the nebula prior to accretion onto the CO parent bodies. Water within the amorphous silicates contributed to the oxidation of the Fe to Fe3+. Low porosity and limited permeability in the primitive materials restricted any fluids from circulating within the parent body. Changes from metamorphic heating released water and increased permeability such that organic matter became homogenized and subsequently partially dissociated generating a reducing environment. It is possible that the CO parent bodies had an onion shell like structure with high petrologic type COs concentrated in the inner part of the asteroid and low petrologic types closer to the surface.