Throughout the Phanerozoic, and possibly throughout geological time, the Earth’s climate has oscillated between greenhouse and icehouse climate states. The most recent transition, from a greenhouse to an icehouse climate state, occurred during the Eocene-Oligocene transition. However, it remains unclear whether CO2 drawdown or some other factors were responsible for long-term cooling during the Eocene (56 to 34 Ma). In order to determine the primary driving mechanisms responsible, we compile and generate new records of marine and terrestrial temperature change during the Eocene epoch using a biomarker approach. Proxy estimates are compared to modeling simulations spanning each stage of the Eocene to help better constrain the drivers of long-term cooling during this time interval.
Our results indicate that terrestrial and marine settings were characterized by a long-term temperature maximum during the early Eocene. During the middle and late Eocene, there is a gradual decline in marine temperatures, especially at high-latitudes. The magnitude of cooling indicated by TEX86 is not supported by fixed-CO2 HadCM3L model simulations and provides indirect evidence that drawdown of CO2 (or some, as of yet unidentified, other factor(s)) was the primary forcing for long-term surface water cooling during the Eocene. This hypothesis is consistent with a new high-fidelity record of CO2 concentrations which constrains the relative decline in CO2 concentration through the Eocene to about fifty per cent (from ~1400 to ~770ppm).
Assessment of Earth’s finite natural resources becomes an increasingly urgent task as they are depleted, yet demand continues to rise. "Peak resources", the time at which production starts to decline, may occur within a few decades for some critical metals and oil. New methods of resource evaluation take advantage of the fractal geometry of georesources. Lode gold deposits, geothermal wells and volcanoes, and conventional and unconventional gas wells all have fractal characteristics that can be assessed by these techniques. These seemingly disparate resources are connected, as they form by fluid fluxes through the crust. Their origin can be considered as a consequence of percolation, bringing a further armory of theory to bear on understanding their formation and distribution.
Extraterrestrial dust falls everywhere, it is on our homes and even on our clothes. These tiny particles come from asteroids and comets and tell us about the origins of our solar system. They are also the fastest dust particles on Earth and their fiery entry into our atmosphere leaves its mark on these objects.
The end-Cretaceous mass extinction is one of the 'big five' events in Earth history, seeing the demise of the non-avian dinosaurs, ammonites and a large percentage of the oceanic plankton. There is an on-going, heated, debate as to whether the bolide impact at Chicxulub (Mexico) or the eruption of the Deccan Volcanics were to blame, or was it a combination of both? Using field information from Denmark, Sweden, Italy, India, Brazil and the USA (Colorado, Texas and Alabama), the case for each possible cause will be reviewed. In some of these areas, especially Texas and Alabama, poor field descriptions have not helped in the debate! One critical issue, based on comparisons with the present day, is the role of ocean acidification, as this appears to be more important than previously thought.
Dinosaurs are the most fascinating and charismatic of all fossil groups. In the last decades, we have found that many had feathers and they gave rise to living birds, so we know more about dinosaurs and their evolution than ever before. Recent discoveries have found that the melanin pigments are often preserved in the feather and skin impressions of dinosaurs, which means that we can reconstruct many aspects of their original colouration. Birds are some of the most colourful animals in existence, and now we can build a narrative of how dinosaurs evolved to give rise to the amazing plumage that we see in hummingbirds, peacocks and harlequin ducks and even how they saw ancient predators and what they ate!
Underground storage of carbon dioxide emitted from fossil fuel combustion and other industrial processes offers the most credible way of achieving the deep reductions in greenhouse gas emissions agreed at last year’s COP-21 climate change conference in Paris.
The regulatory framework for underground CO2 storage has been set up via a European Directive. In this there is a regulatory requirement to prove that storage sites are not leaking, that their current behaviour is understood, and that stored CO2 will continue to be contained in the long term. Time-lapse monitoring at storage sites, using geophysical and geochemical techniques provides the means by which these quite challenging objectives can be met.
Industrial-scale CO2 injection has been in operation at the Sleipner gas field in the Norwegian North Sea since 1996, with more than 16 million tonnes of CO2 now stored. A comprehensive time-lapse monitoring programme has been carried out, with a series of 3D seismic surveys providing strikingly clear images of the CO2 plume in the storage reservoir and its progressive spreading and growth with time. These can be matched with numerical fluid flow models to demonstrate that subsurface processes are well understood.
Other monitoring datasets from storage sites worldwide also provide robust indication that we do understand the key physical processes controlling the behaviour of stored CO2 and that longer-term predictions of storage site performance are likely to be reliable.
One of the mysteries of the sea are the large number of seamounts that rise up on the seabed and, in a few cases, break surface to form oceanic islands. Volcanic in origin, seamounts are widely scattered throughout the world’s ocean basins, especially in the Pacific. Recent estimates suggest that there maybe as many as 200,000 seamounts with heights that range from 0.1 to 6.7 km above the surrounding seafloor. Seamounts are generally circular in shape, have pointed, star-shaped, curved, or flat tops, and are often capped by a coral reef. They are of geological interest because they record the motions of Earth’s tectonic plates and the magmatic ‘pulse’ of its deep interior. They are also significant as ocean ‘stirring rods’, biodiversity ‘hotspots’, and hazards for megathrust earthquakes, submarine landslides, and navigation. Statistical studies suggest that there are as many as 24,000 seamounts higher than 1 km still to be discovered. The charting of these seamounts and the determination of their morphology, structure, and evolution is one of the many challenges facing marine geologists in the future.
Pterosaurs were the first vertebrates to take to the skies, and the largest animals ever to achieve powered flight. The largest had wingspans rivalling small airplanes at 10-11m. The biggest birds today are nowhere near this size, with albatross wingspans of 3-4 m., and extinct birds may have reached up to 8 m. in size. Why were pterosaurs able to reach this great size? How were they able to fly? Exactly how heavy were these animals? With unique adaptations, pterosaurs were able to dominate the sky for over 150 million years.
This talk focuses on the use of microscopic fossils from deep sea sediments and how they were used in recent scientific coring expedition to the Indo-Pacific 'warm pool' - the hottest part of the oceans.
Professor Pearson will describe how microfossils are used to date sediment cores recovered from hundreds of metres below the sea bed, stretching back millions of years in time; what can be learned from them about evolution and extinction in the oceans; and how the chemistry of the shells is used to track changes in temperature, the waxing and waning of the ice sheets, and the role of carbon dioxide in shaping earth's climate history.
In many parts of England, the extraction of building stone has long ceased, and many original source quarries have closed or been lost. Consequently, obtaining detailed information on distinctive local stones (or suitable alternatives), their source and use for historic building or conservation purposes is often difficult.
The Strategic Stone Study (‘S-cubed’) is the first country-wide comprehensive study undertaken of England’s buildings stones, their use in vernacular buildings and the identification of historic source quarries. Initially developed by Historic England (formerly English Heritage) as a response to difficulties sourcing suitable replacement stone for historic buildings, the study aims to provide freely accessible (on-line) data for anyone involved in sourcing stone for this purpose. Working with the British Geological Survey, the study has also involved local geologists and heritage building specialists.
This presentation explains the background that led to ‘S-cubed’, its subsequent development and the roll out of the latest features including interactive County Atlases and datasets with GIS search facilities. A series of recent case studies also demonstrate how data from ‘S-cubed’ can be used to further promote England’s building stones, to safeguard their future (for example by informing Mineral Safeguarding Areas) and help develop pragmatic approaches to the (re)opening of small scale building stone source quarries through local mineral planning policies.