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Ostracods form a significant component of the Late Ordovician fossil fauna of the Ellis Bay Formation, Anticosti Island, Canada. Sixty-two ostracod species are identified, belonging to 36 genera. These include 14 species described as new, and 13 species described in open nomenclature. The ostracod fauna reveals new and important data bearing on the biostratigraphical, palaeogeographical and palaeoecological significance of the Ellis Bay Formation. The stratigraphic distribution of the ostracods permits the recognition of four successive intervals: (A) the Longiscula subcylindrica Biozone, (B) the Eurychilina erugoface Biozone, (C) the Tetradella anticostiensis Biozone and (D) an Interregnum. Stratigraphical intervals A, B and D can be related to Copeland’s (1973) ostracod biozonation for the Ellis Bay Formation. Biozone C is equivalent to three of Copeland’s (1973) ostracod sub-zones. Presence/absence analysis of the ostracod distribution patterns in the Ellis Bay Formation identifies two palaeoecologically discrete assemblages: an open marine assemblage characterises most of the formation (lithostratigraphical members 1 to 6); whilst a lower diversity assemblage typifies the uppermost Member 7. Biogeographically, the Ellis Bay Formation ostracod fauna is typically North American (Laurentian), but also shares affinities with the Late Ordovician ostracod assemblages of palaeocontinental Baltica and Avalonia.

The depleted mantle producing mid-ocean ridge basalt (MORB) can be divided into chemical domains through variations in its radiogenic isotope compositions. Through performing whole-rock ¹⁴³Nd/ ¹⁴⁴Nd and ¹⁷⁶Hf/ ¹⁷⁷Hf analyses of MORB-like material in Rheic Ocean ophiolites, the range of the Indian Ocean-type mantle domain has been spatially and temporally traced. Isotope results presented in this study extend the known range of Indian Ocean-type mantle by highlighting its existence since c. 480 Ma, and documenting its pervasive distribution through Europe in the Devonian (c. 410 Ma to c. 390 Ma). Ophiolites from the Rheic Ocean generally contain radiogenic ¹⁴³Nd/ ¹⁴⁴Nd and ¹⁷⁶Hf/ ¹⁷⁷Hf, above estimates for the depleted mantle (DM) at the time of formation. These values indicate a history of melt depletion in the mantle pre-dating formation of the Rheic Ocean and depletion model ages (TDM) suggest this occurred throughout the Neoproterozoic-Cambrian. Highly radiogenic ¹⁷⁶Hf/ ¹⁷⁷Hf in the Careón ophiolite, NW Galicia, extend the known range of εHft in MORB from < +25-30 up to +39. The generally decoupled isotope compositions and increased ¹⁷⁶Hf/¹⁷⁷Hf common in the Rheic Ocean ophiolites is inconsistent with a model of mantle depletion, storage and re-melting. Instead, isotope compositions may highlight a complex history of mantle depletion, re-fertilisation, and mixing. Specifically, the isotope compositions may be reproduced by mixing Pacific Ocean-type mantle with anciently depleted and subsequently re-fertilised sub-continental lithospheric mantle. This modelling indicates that the Indian Ocean-type compositions in the Rheic Ocean ophiolites may have been produced by shallow contamination of the mantle, and likewise, the Indian Ocean-type mantle signature may also be a shallow mantle feature. The appearance of Indian Ocean-type mantle in the incipient Rheic Ocean preserved in the Pulo de Lobo ophiolite, S. Iberia (c. 480 Ma), coupled with a lack of such material in the coeval Ballantrae Complex from the Iapetus Ocean, suggests that the signature may be intrinsically related to Gondwana.

The taxonomy of benthic foraminifera recovered from 160 core samples over depth 20.59 m and representing the past ~597 Kyr (sedimentary deposit of the Tarantian and Ionian stages) at Bowers Ridge, Bering Sea IODP site U1342, includes some 52 species from 41 genera and 22 families: these species are given formal taxonomic treatment with detailed illustration. A further 16 species are discussed in open nomenclature. Foraminifer assemblages are dominated by species of Takayanagia delicata, Uvigerina bifurcata, Islandiella norcrossi and Alabaminella weddellensis accounting for more than 58 % of all specimens recovered. In addition to their taxonomic identification, this study interrogates the relationship between benthic foraminifera and interpreted changes in oxygen concentration and productivity during a series of late Quaternary glacial– interglacial cycles at site U1342. In particular, the species Bolivina spissa (Cushman) – thought to record changes in seabed oxygen level, shows no correlation between test pore density and interpreted bottom water oxygen level (BW-O2), suggesting that oxygen is not the sole driver influencing the distribution and morphology of this species. Further assessment of the total foraminiferal assemblages at site U1342 - using the sedimentological context and the proportion of deep infaunal species as a proxy for low oxygen conditions at the seabed, and shallow infaunal species as a proxy for a welloxygenated seabed, identify eight broadly defined temporally successive benthic foraminiferal intervals through the sampled core. Three of these intervals, between depths 0 - ~5.40, ~ 6.50 - 9.00 and ~16.90 - 18.67 m-CCSF, signal a well-oxygenated sea bed, whilst the other five intervals suggest increased phytodetritus flux to the seabed, coupled with variations in seabed oxygen level. In general, there is no clear connexion between these intervals and the glacial-interglacial oscillation at the site during the past ~597 ka, suggesting that ecological influences on foraminiferal distribution at Bowers are complex.

Landslides pose a significant risk to life and infrastructure in Papua New Guinea (PNG). The combination of rugged topography and high seismicity makes PNG highly susceptible to large-volume, earthquake-induced landslides, while the climate encourages widespread rainfall-induced landslides. Of the two triggering mechanisms, rainfall offers the best opportunities for the development of early warning/forecasting systems, as meteorological models continue to improve in skill and resolution. To understand the relationships between rainfall and landslides, studies have conventionally looked to develop landslide-triggering rainfall event thresholds. Such thresholds can form the basis for early warning/forecasting systems. In this thesis, satellite-based precipitation estimates from the Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) are used to examine characteristics and relationships between rainfall and landslides. These data, in conjunction with Bayesian statistical approaches, were then used to develop landslide probabilities based on rainfall events of varying duration and magnitude. Understanding the landslide triggers is only one aspect of slope instability. Environmental control factors, such as slope or curvature, can enhance or reduce the likelihood of slopes to fail. Therefore, multispectral imagery and high resolution GeoSAR (synthetic aperture radar) digital elevation models have been exploited to verify and map landslide scars in different regions of PNG. These data also support the development of landslide susceptibility maps, providing detailed information on the terrain and structures important for slope instability. Using fuzzy relation-based assessments these data were used to produce landslide susceptibility maps which differentiate areas of low/no susceptibility from those with high susceptibility. Overall, the satellite and airborne techniques have provided the tools to understand landslide occurrence relative to changes in rainfall and susceptibility, which can form the basis of early warning/forecasting models.

The Fenland of East Anglia is the largest area of Holocene deposits in Britain (c. 4000 km[superscript 2]) and some successions reach a thickness of 30 m. A complex palaeoenvironmental landscape has been progressively revealed as the overlying peat has wasted away to reveal exceptionally preserved roddons. Roddons are defined as dendritic ridge systems, up to 1 m high, that meander across Fenland areas. They are interpreted as being the surface expression of silted-up tidal creeks. Three generations of East Anglian roddons have been identified, each being related to a major “transgressive” event between about 2000 and 6000 yrs BP. Soon after the tidal creeks and channels had been established, they were choked by sediment (silts and fine sands) derived from a nearby shallow marine environment, perhaps following major (storm-induced?) physiographic changes. The final stage in their formation occurred after 17th century Fenland drainage, with compaction, shrinkage and wind ablation of the surrounding salt marsh clays and peats, leaving the more resistant channel infill as topographic highs. Roddon deposits contain rich assemblages of autochthonous, low marsh foraminifera with rarer ostracods (together with allochthonous taxa and fossils reworked from bedrock); assemblages differ from trunk to tributary roddons. A late-stage channel incised into a roddon at Must Farm, near Peterborough, is filled predominantly with clays containing freshwater ostracods and molluscs, together with riparian archaeological remains. This freshwater channel, therefore, represents a distinctly different palaeoecological regime compared to that of the roddons. Any future marine transgression will take place across an anthropogenically modified Fenland where the topographically positive roddons will act as barriers and islands that will affect marine ingress.

Shallow marine late Neogene and Quaternary sedimentary deposits around coastal Antarctica and South America contain abundant fossil bivalves, but these have rarely been utilised for palaeoclimate work. Due to their incremental growth, bivalves contain a wealth of information relating to the environment they were living in, including temperature (using δ[superscript 18]O) and productivity (using δ[superscript 13]C). A repeatable method of assessing the preservational state of fossil bivalves using a combination of techniques has been developed to ensure only pristine material is analysed for stable isotopes. These include inspection of the lamellar structure under an optical microscope, observation of luminescence using cathodoluminescence and identification of internal crystal structure using scanning electron microscopy. A targeted study of modern pectinid, cardiid and hiatellid bivalves confirm their suitability for reconstructing sea surface temperatures (SSTs), although in the case of hiatellids an understanding of the local environment is essential for an accurate interpretation of oxygen isotope records. Stable isotope analysis of pristine late Neogene (ca. 6.5 to 2.5 Ma) pectinid bivalves from James Ross Island, Antarctic Peninsula and pectinid, cardiid and hiatellid bivalves from the Vestfold and Larsemann Hills in the East Antarctic, record two distinct environmental signals: 1) warmer than present summer SSTs of up to +4.5°C, consistent with a number of other shallow-shelf and deeper water marine fossil proxies, including bryozoans, silicoflagellates and cetaceans, and with General Circulation Model simulations (e.g. PlioMIP) and, 2) seasonal fluxes of freshwater from local ice sheets, artificially decreasing δ[superscript 18]O ratios. Stable isotope analysis of late Pliocene to Quaternary (ca. 3.5 to 0.2 Ma) Chlamys bivalves and Argopecten purpuratus from the Mejillones Peninsula and Coquimbo, northern Chile, identify similar SSTs (+13 to +18°C) compared to present and suggest El Niño-Southern Oscillation (ENSO) variation has been present in the south-eastern Pacific since the late Pliocene, a signal consistent with climate model predictions. This study emphasises the importance of developing new climate proxies that identify seasonal variation, and which can be used in conjunction with other environmental proxies to provide detailed palaeoclimate data for little studied Neogene successions of the coastal zones of Antarctica and the south-eastern Pacific.

Palynological investigation of the Carboniferous-Permian Nilawahan Group of the Salt Range, consisting of the Tobra, Dandot, Warchha, and Sardhai formations, led to age determination and palynostratigraphic correlation. The sedimentological analyses of these units resulted in the palaeoenvironmental syntheses. The palynological assemblages from the Late Pennsylvanian Tobra Formation correlate with the Oman, and Saudi Arabia Palynological Zone 2 (OSPZ2), the South Oman 2165B Biozone, the eastern Australian Microbaculispora tentula Oppel-zone and western Australian Stage 2 (sensu Backhouse 1991). The Tobra Formation represents deposition via glacio-fluvial processes associated with the final stages of the Gondwana glaciation. The overlying Dandot and Warchha formations are found to be barren of palynomorphs during the present study. The Dandot Formation occurs between the Upper Pennsylvanian Tobra Formation, and the Artinskian Stage Warchha Formation and it therefore ranges from the Late Pennsylvanian to Artinskian. The Dandot Formation represents deposition in an intertidal to shallow marine settings that developed as sea level rose following waning of the Carboniferous-Permian glaciation. The Warchha Formation is dated as Artinskian Stage, based on the presence of plant megafossils. The Warchha Formation represents deposition in a fluvial system. The Sardhai Formation at the top of the Nilawahan Group is dated as Middle Permian, Wordian Stage, based on the presence of stratigraphically diagnostic Florinites? balmei, and is correlated with the Oman and Saudi Arabia Palynological Zone 6 (OSPZ6). This correlation shows that Florinites? balmei is endemic to the southern neo-Tethys area. The Sardhai Formation was deposited in a shallow marine setting, associated with neo-Tethys opening and sea floor spreading during the Wordian.

Ostracods form a numerically important component of certain Late Ordovician faunas of the Girvan district, southwest Scotland. Fifty-two ostracod taxa are identified, including twenty-three discussed in open nomenclature, and seventeen species that are considered as nomen dubia. The fauna reveals new and important data bearing on the biostratigraphic, palaeogeographic and palaeoecologic significance of the Girvan Lower Palaeozoic succession. Much of the Ordovician ostracod fauna of the Girvan district preserved in clastic deposits represents transported material. However, those ostracods from the early Katian Craighead Limestone Formation define shallow marine and open marine faunas respectively. The Girvan ostracods include many short-ranging species which are useful for inter-regional correlation of the Late Ordovician succession of Scotland and North America; these include Hippula ventrospinosa, Balticella deckeri, Eurychilina sunbloodensis and Baltonotella parsispinosa which characterize Sandbian age strata, and Kinnekullea comma which is typical for the Katian (anceps graptolite Biozone). Biogeographically most of the Girvan fauna is typically of North American aspect at the species level but from the early Katian onwards shows generic links with Baltica and Avalonia. The spatial and temporal distribution patterns of the Girvan Late Ordovician ostracod fauna are assessed in the context of the entire Late Ordovician Laurentian ostracod assemblage particularly for the Sandbian interval, where ostracod diversity was highest at species and genus level. Multivariate analysis demonstrates that geography had the strongest control on the global distribution of Ordovician benthic ostracods. Within Laurentia Sandbian ostracods show striking inter-basinal endemism at species level, ranging from 25% endemic in the Foxe Basin of the Franklin district, Canada to 75% in the Michigan basin. This pattern of endemism is common in other benthic groups such as brachiopods, and may indicate rapid speciation in microhabitats. Despite the strong overprint of local endemism, pan-continental faunal differences are noticed between the midcontinent and marginal Laurentian ostracod assemblages that are confirmed by multivariate analysis, and these allow the demarcation of a ‘Midcontinent’ and a southern ‘Marginal’ province for the Sandbian. Ostracod assemblages of the two provinces appear to have been controlled by physical parameters such as temperature and salinity which are related to water depth and latitude.