3 Feb 2016 – Simon Kohn (Bristol)
Title: Diamonds: precious stones yield precious clues to deep Earth processes.
Abstract: Diamonds and their inclusions are key samples for looking at processes that occur deep in the Earth and far back in Earth history. Although most diamonds originate from depths of 150-200 km, some are known from the transition zone and lower mantle, and inclusions within diamonds gives ages back to at least 3.5 Ga. The key to the usefulness of diamond is the extraordinarily low diffusion rates within the structure, which enable inclusions to remain isolated from the external environment of the diamond and defects within the diamond structure to change slowly, and at predictable rates, over long periods of residence in the mantle.
In this talk I will focus on two contrasting ways in which diamonds can provide unique information on the evolution of the Earth. Firstly I will describe how structural defects in diamond evolve at different rates during storage in the lithosphere and thus how they can be used to constrain the temperature history of the lithosphere from different cratons. I will show results from high-resolution-infrared-mapping that indicate multiple growth phases in many localities, and show how study of the systematic behaviour of a planar defect (called a platelet) in diamond provides novel insights into the history of the lithosphere. The second example that I will discuss is a suite of superdeep diamonds from Brazil. These diamonds show unambiguous evidence for a subduction-related origin, and we have combined observations on the mineralogy, geochemistry and stable isotopic composition with experimental constraints to develop a model for superdeep diamond formation as part of a deep carbon cycle.
17 Feb 2016 – Wolfgang Maier (Cardiff)
Title: The Bushveld Complex, South Africa: petrogenesis and mineralisation
Abstract: The Bushveld Complex is the product of what was one of the world's largest magmatic events. The event comprised the largest layered mafic-ultramafic intrusion globally (the 400 x 300 km Bushveld Complex) plus the ~150 x 100 km Molopo Farms Complex in Botswana, the Phalaborwa carbonatite located >100km to the east of the Bushveld, and several other small mafic intrusions. Associated with these mafic rocks is the largest A-type granite on Earth (the Lebowa granite suite), and a vast rhyolitic lava flow field (the Rooiberg felsites) whose remnants are preserved over 800 km in EW direction and 300 km in NS direction. The Bushveld event hosts the world's largest PGE, Cr, V, as well as vast Ni-Cu, apatite, gold, andalusite, magnesite, and dimension stone resources, and numerous other mineral deposits. The present talk will review the petrogenesis of the Bushveld Complex, including its mantle source and tectonic setting, and the origin of the PGE-Cu-Ni-Cr-V mineralisation.
24 Feb 2016 – Philip Mannion (Imperial)
Title: Why the long face? 250 million years of decline on the crocodile line
Abstract: Projected global warming of 2.0–4.8°C over the next century could have profound repercussions for environmentally sensitive crocodylians. The fossil record of crocodylians and their extinct relatives reveals a rich evolutionary history, prompting questions about causes of long-term decline to their present-day low biodiversity. Climatic drivers of subsampled crocodylian biodiversity are analysed over their 250 million year history. Biodiversity peaked during the earliest intervals of the group’s history and was punctuated by extinctions and radiations during the Mesozoic. Overall diversity was unaffected across the Cretaceous/Paleogene mass extinction 66Ma, although only three clades survived, with these rapidly diversifying. Biodiversity and environmental changes correlate strongly, with long-term decline of terrestrial taxa driven by decreasing temperatures in temperate regions from ~35Ma, and biodiversity decreases at lower latitudes matching patterns of increasing aridification in Africa and South America during the late Neogene. However, there is no relationship between temperature and biodiversity for marine species, with sea-level change and post-extinction opportunism demonstrated to be more important drivers. Range expansion towards the poles occurred during warm intervals, with present day restriction to the subtropics corresponding to cooling. Although their fossil record suggests that current global warming might promote long-term increases in crocodylian biodiversity and geographic range, the 'balancing forces' of anthropogenic environmental degradation complicate future predictions.
9 Mar 2016 - Lars Hanson (Oxford)
Title: Causes and consequences of upper-mantle seismic anisotropy: The link between olivine microstructure and the nature of plate tectonics
Abstract: The link between plate tectonics and the dynamics of Earth's upper mantle is heavily dependent on the material properties of mantle rocks. Seismic anisotropy (the dependence of seismic wave speed on propagation direction) has been a valuable tool in determining the behavior of tectonic plates through our understanding of the microphysics of olivine deformation. However, major questions remain. For instance, can we precisely map seismic anisotropy to flow and kinematics? What is the best interpretation of the seismic structures that are used to define the lithosphere? Can our current understanding of upper-mantle mechanics explain the major features of plate tectonics?
The results of a campaign of laboratory experiments on olivine aggregates that yield new insight into the mechanisms of upper-mantle deformation will be presented. This set of experiments provides a link between seismic properties, deformation mechanism, rheological behavior, and composition.
16 Mar 2016 – David Schultz and Jonathan Fairman (Manchester)
Title: Build Your Own Earth: A Climate and Paleoclimate Tool for Teaching and Research.
Abstract: Imagine the ability to build your own worlds by selecting various planetary characteristics: distance from the Sun, tilt of the axis, location of continents, oceans and mountains, atmospheric composition, etc. You would enter these characteristics on a web page, and then, after pushing the “Go” button, a climate model would run in the background and produce the climate on that world for you. Although producing such an instantaneous simulation of climate is not possible due to the speed of today’s computers, we nonetheless persisted with our vision. The result was Build Your Own Earth (http://www.buildyourownearth.com/), a free web-based tool to engage students in understanding the controls on Earth’s climate. Three types of simulations are performed: 29 simulations using the modern-day Earth vegetation and topography but varying greenhouse gas forcing, solar constant, and orbital parameters, 11 idealized simulations (e.g., aquaplanet, terraplanet, and ice planet), and 10 palaeoclimate simulations ranging from the Last Glacial Maximum to the Ediacaran (600 million years ago). This presentation presents the tool and describes how Build Your Own Earth is used in teaching a massive open online course (MOOC) and in the introductory Earth science course for first-year students at Manchester. The simulations have been incorporated into journal articles to demonstrate the seasonal cycle in the Middle Jurassic in Argentina. Finally, we get the audience thinking about how they can use the tool for undergraduate or graduate dissertations, teaching and research projects.
20 Apr 2016 – Jessica Barnes (Open University)
Title: Using lunar apatite to understand the history of volatile accretion to the Earth and Moon
Abstract: For decades our Moon was considered a volatile-depleted, anhydrous planetary body. It wasn’t until very recently that volatiles were discovered lurking in samples of the Moon brought back by the NASA Apollo missions and in some lunar meteorites. Of great interest to the lunar community has been the only ubiquitous mineral in lunar rocks that is known to contain volatiles: the calcium phosphate mineral apatite. Lunar apatite mainly occurs as fluorapatite but it can also harbour varying amounts of H (as OH) and Cl in its crystal structure. The robustness of apatite has allowed us trace important magmatic and planetary processes through geological time. In this talk I’ll present an overview of where in the Solar System we think lunar water may have come from and my ongoing work trying to understand the processes that may have caused the chlorine isotope anomaly of the Moon.
4 May 2016 – Giulio Di Toro (Manchester)
Title: Fault weakening mechanisms in carbonate-bearing rocks at seismic deformation conditions
Abstract: Moderate to large earthquakes (e.g., Wenchuan Mw 7.8, 2008; L'Aquila Mw 6.1, 2009) often rupture and propagate along faults in carbonate-bearing rocks (dolostones, limestones, marbles, etc.). Because of the large stresses (hundreds of MPa at >10 km depth) and slip rates (about 1 m/s ) involved, a large amount of frictional work rate (product of frictional shear stress per slip rate) is dissipated along faults during earthquakes. The frictional work rate can be so large (1 to 100 MW m-2) as to grind and mill the rock (producing particles of nanometric size, or nanopowders) and trigger mechanically- and thermally-activated chemical reactions. Under these extreme deformation conditions, the fault surfaces in carbonates are separated by fluids or other tribochemical products (nano-powders, amorphous and decarbonation products, etc.). It follows that earthquake physics is controlled by the mineral reactions and phase changes triggered by the passage of the seismic rupture and, as a consequence, by the rheology of the reaction products. Here, by exploiting the results of (1) field and microanalytical studies conducted on natural fault products, and (2) experimental studies reproducing the extreme deformation conditions typical of seismic slip, we will discuss the mineral reactions and phase changes concomitant to and responsible of fault weakening in carbonates during earthquakes.
11 May 2016 – Iain Stewart (Plymouth)
Title: Between a Rock and a Hard Place: communicating geology to society
Abstract: Geoscientific knowledge and understanding lies at the heart of many of the most critical societal issues that face us in the 21st century. The pressing human challenges of natural disaster reduction, energy supply and security, and mineral and water resource management, rest on geological foundations. And yet, outside of the academic and industrial geoscience community there is a limited appreciation of Earth Science, especially among policy makers. Geology , it seems, lies out of sight and out of mind. For that reason, geologists are increasingly being encouraged to communicate more broadly what they do and what they know. Yet how can we do that when, for most people, geology is about 'stones' and stones are 'boring'! It is a problem compounded by the fact that many of our most acute geo-issues are rooted in the unfamiliar realm of the deep subsurface. This talk will use the experience of popularising geoscience for mainstream television to explore ways in which geologists can make our research connect better with the dissonant public, and in doing so forge more effective strategies for meaningful public engagement.
Speaker: Rod Robinson, National Physical Laboratory. Topic: Differential Absorption Lidar (DIAL) measurements of GHG emissions
Rod Robinson from the National Physical Laboratory has been involved in the development and use of the DIAL technology for over 20 years. DIAL is an optical remote sensing technique which is able to map the concentration of gases in the atmosphere. The talk will cover the background and capabilities of the this optical remote sensing technology, giving a brief summary of the development of the technique bringing it up to date with the latest system developed at NPL in 2014. Rod will present examples of the use of the technique for identifying and quantifying GHG emissions into the atmosphere, and give a summary of current research and future plans for the technology.
Speaker: Margaret Hartley, The University of Manchester. Topic: Diffusion modelling in magmatic crystals
Many active volcanoes exhibit significant changes in seismicity, ground deformation and gas release in the hours, days and weeks preceding an eruption. One of the principal challenges in modern volcanology is to interpret these signs of volcanic unrest in terms of sub-surface magmatic processes such as the pre-eruptive storage, transport and degassing of magma. These processes may be recorded in the compositional zonation of magmatic crystals. By modelling these compositional changes with diffusion chronometry, it is possible to constrain the timescales over which various magmatic processes are occurring.
Recent studies have shown that crystal residence timescales and magma recharge rates constrained by diffusion modelling can be temporally linked with seismic, geodetic and/or gas monitoring records in the lead-up to eruptions at volcanoes including Mount St Helens, Etna and Ruapehu. This indicates that petrologically determined timescales of magmatic processes can provide an important framework for the interpretation of seismic, geodetic and gas monitoring data in regions where the last known volcanic eruption occurred before the advent of modern monitoring techniques. One such location is Iceland's Eastern Volcanic Zone (EVZ). Magmatism on the EVZ over the Holocene period has been typified by flood lava eruptions (>1 km3 of erupted lava) such as the AD 1783 Laki eruption. Large-volume, long-lived eruptions such as Laki have historically produced significant global climatic, environmental and societal impacts, and similar effects may be expected in the event of future flood lava eruptions.
This talk will demonstrate how diffusion stopwatches in olivine crystals from Laki can be used to determine the timescales of magmatic processes operating in the lead-up to flood lava eruptions. By comparing these timescales with historical accounts of seismic unrest in the days and weeks preceding the Laki eruption, the utility of petrological data in interpreting seismic and geodetic monitoring signals in Iceland will be discussed.
Speaker: Mike Burton, The University of Manchester Topic: From the mantle to the stratosphere: magmatic processes and their impacts
Magmatic processes such as crystallisation, degassing, and gas-magma decoupling control the rheological evolution of magma during its ascent to the surface, and therefore the style of volcanic activity. These eruption styles vary widely, from Plinian eruptions that impact on global climate to lava flows which destroy local infrastructure. Understanding the processes which mediate the transitions between different styles of activity is therefore a key element in mitigating volcanic risk. In this talk I present case studies of volcanic eruptions and examine their impacts on local populations and climate, before examining in detail the geochemical and geophysical observations which reveal the processes driving the activity, using novel models of magma ascent. Some novel gas imaging techniques and radiative transfer challenges will be described. The activities and questions being addressed in my ERC project, CO2Volc, will also be presented.
Prof. Burton's areas of research include measurements, experiments and modelling of magmatic processes, with a particular focus on measurements of volcanic gases from ground, air and space. He studied for his PhD with Prof. Rod Jones in the Center for Atmospheric Science in Cambridge, with a focus on ground-based infrared remote sensing measurements of ozone-destroying chemical species in the stratosphere. After his PhD he began work as a PDRA in the Geography department of Cambridge, working with Prof. Peter Francis and Prof. Clive Oppenheimer on the application of open-path Fourier transform infrared spectroscopy to measure volcanic gases. This proved to be highly effective in volcano monitoring, and in 2000 he joined the National Institute for Geophysics and Volcanology (INGV) in Catania, Italy, leading a team of researchers and technicians within the Etna volcano observatory performing remote sensing measurements of gas emissions from Italian volcanoes. After participating in the response to four major eruptions on Etna and Stromboli in 2008 he transferred within INGV to the Pisa office to focus on wider scientific questions, leading in 2012 to the award of an ERC consolidator grant entitled "CO2Volc: Quantifying the global emissions of volcanic CO2". In March 2015 he joined School of Earth and Environmental Science in the University of Manchester as a new Chair in Volcanology. He has published 53 papers in ISI journals and has an h-index of 25.
Speaker: Tom Scott, University of Bristol. Topic: A Drone's eye perspective of radiological clean up around Fukushima
This seminar will describe the race to develop a semi-autonomous drone system, its deployment in Japan and the associated research being conducted on the radiological constituents of the Fukushima fallout material.
Dr Tom Scott is reader in Materials Science. His research interests are Geochemistry and Metallurgy of uranium – specialising in the oxidation/corrosion behaviour of uranium, and methods for its environmental remediation. His active interests also include the geochemistry of iron and iron bearing minerals for the uptake and environmental remediation of heavy metals and radionuclides.
Speaker: Jonathan Reid, University of Bristol. Topic: From the laboratory to the atmosphere: What can we learn from studying single aerosol particles?
Abstract: Aerosol particles play a wide range of roles in the atmosphere, impacting on climate and influencing air quality. Laboratory studies on well-defined systems can provide important insights into the properties of ambient particles and the processes they undergo. We will review a range of novel tools for isolating and manipulating individual particles and for characterising the processes they undergo. In particular, we will explore the factors that govern the kinetics of water transport in aerosol, the partitioning of semi-volatile organic compounds between the gas and condensed phases, and the optical properties of aerosol.
Jonathan Reid is Professor of Physical Chemistry at the University of Bristol. His research focusses on applying novel optical tools to study the processes that occur on individual aerosol particles. He has held an EPSRC Advanced Research Fellowship and a Leadership Fellowship, and was the recipient of the 2001 Harrison medal, the 2004 Marlow medal and the 2013 Corday-Morgan Medal of the Royal Society of Chemistry.
Speaker: Carl Stevenson, University of Birmingham. Topic: Novel applications of anisotropy of magnetic susceptibility (AMS) analyses: rock, ice and nanoparticles
This will be an overview of current activity with some seminal findings where we are using AMS and magnetic susceptibility techniques in a diverse range of studies from ice and glacial sediments, to evaporite, to studying nanoparticles in porous rocks. Dr Carl Stevenson is a structural geologist with a focus on the emplacement and subsurface distribution of igneous and volcanic rocks. His research uses rock magnetism, geophysics and petrology to determine the large-scale geometry and internal architecture of intrusions and has led to breakthroughs in understanding magma transport and accommodation in the Earth’s crust.
Speaker: Jacob Fugal, Mainz, Germany. Topic: Airborne digital holographicsystem for cloud particle measurements
Abstract: Clouds play an important role in the earth’s water cycle, atmospheric energy budget, and atmospheric chemistry. The behavior of clouds depends, in part, on so-called „cloud microphysics“, or processes involving cloud particles that occur on spatial scales less than ~1 cm. To understand these processes, we use holography to examine cloud particles in their local threedimensional development on cm scales.
Jacob Fugal (Ph.D. Engineering Physics, 2007, Michigan Tech, USA; BS Physics, 2003 Brigham Young University, USA) is a scientist at the Institute for Atmospheric Physics at the University of Mainz in Germany where he leads the holography lab under Prof. Stephan Borrmann. Over the last decade, Fugal and others have built three airborne holographic instruments and several lab instruments to measure cloud particles. They have also written “Holosuite“ software to process the holograms to find and measure cloud particles.
Speaker: Monika Kusiak (Polish Academy of Sciences)
Title: Preservation versus perturbation of zircon chemistry through Archean metamorphis
Speaker: Matt Van Ginneken (Imperial)
Title: Micrometeorites and the flux of extraterrestrial matter to Earth.
Abstract: Micrometeorites are extraterrestrial dust particles 10 µm to 2 mm in size that reach the Earth’s surface. In term of mass, the flux of micrometeorites accreting to Earth is estimated to be 30,000 ± 20,000 tons per year, compared to approximately 50 tons for meteorites. Despite their importance, the origin of micrometeorites is still unclear. In the early nineties, the discovery of the first micrometeorites collections in Greenland and Antarctica allowed scientific teams to specialize in the study of micrometeorites. Furthermore, recent increase in quantity and quality of samples and major technical advancements allow their study in greater details. Here I will present recent studies focusing on the nature of the precursors of micrometeorites. I will also explore studies aiming at estimating the present and past flux of micrometeorites to Earth.
Speaker: Alex Liu (Bristol)
Title: Tracking animal evolution via the Ediacaran trace fossil record
Abstract: In recent years it has become widely acknowledged that animals evolved prior to the 'Cambrian explosion' of diverse metazoan body plans, with molecular studies predicting an animal origin potentially as early as 750 Ma. Despite this, the biological affinities of the most likely fossil candidates for early animals, the Ediacaran macrobiota, remain elusive. In this talk I will explain how the trace fossil record may be used to independently track major morphological and behavioural advances amongst early metazoans during the late Ediacaran Period. Application of SEM and CT studies to recently discovered ichnological assemblages from Siberia, Canada, and Brazil, in combination with morphological and petrological approaches, validates trace fossil interpretations for this material, reveals interesting taphonomic insights, and demonstrates that multiple complex metazoan behaviours existed several million years before the Cambrian. Trace fossils may therefore provide meaningful fossil constraints for emerging molecular clock studies into metazoan evolution and diversification.
Speaker: Christine Lane (Manchester)
Title: Toward a Late Quaternary tephrostratigraphic framework for connecting widespread palaeoenvironmental archives
Abstract: Understanding the spatial and temporal variability of climate forcing and environmental responses relies upon comparison of data from widespread palaeoenvironmental archives. Accurate, precise and independent chronologies for such records are essential; however this remains a challenge in many environments, often preventing the valid comparison of detailed palaeo-proxy records. Many studies have now shown that volcanic ash (tephra) can be detected in terrestrial and marine sediments thousands of kilometres from their source, often as microscopic or “cryptic” layers. As well as offering opportunities for both direct (e.g. by 40Ar/39Ar methods) and indirect (e.g. by associated 14C dates) dating of the sediment sequence, tephra layers can provide stratigraphic tie-lines between archives, facilitating precise correlations at single moments in time. Furthermore, where two or more tephra layers are co-located in multiple records, rates of change can be compared within a period of equivalent duration, even in the absence of absolute age estimates.
This talk will highlight results from investigations into the presence of visible and non-visible (crypto-) tephra layers within terrestrial palaeoenvironmental records of the last ~150 ka BP from across Europe and East Africa, which are revealing the potential to (i) correlate palaeoclimate archives over continental distances within regional tephrostratigraphic frameworks; (ii) provide age constraints for individual core chronologies, in particular beyond the limits of radiocarbon dating; and (iii) increase our knowledge of the history of Late Quaternary explosive volcanism in these areas.
Spealer: Bogdan Antonescu (Manchester)
Title: What do we know about tornadoes in Europe?
Abstract: Our current knowledge of the climatology of tornadoes in Europe has been built from historical collections of tornado reports, cases studies and local climatologies. Unfortunately, these datasets were limited by inconsistencies in observational networks and reporting practices across Europe and only allowed the development of a simplified and inaccurate pan-European tornado climatology. Recently, this situation began to change with more tornadoes reported in the last decade compared with the previous period, and with reports coming now from the majority of European countries. Thus, we are now able to build a more accurate and complete climatology of tornadoes in Europe.
The talk will present recent research conducted with David M. Schultz and Fiona Lomas from the University of Manchester, in which the large body of knowledge resulted from the previous efforts of understanding tornadoes in Europe has been synthesized. The talk will give an overview of the history of tornado observations and tornado datasets in Europe (What do we know about tornadoes in Europe?), and will show how be using these datasets we can build a tornado climatology (Where are the tornado hot-spots in Europe?; There is a ‘tornado season’ in Europe?; Are European tornadoes less intense compare with those from the United States?), concluding in a discussion of the major influences on the evolution of tornado datasets in Europe.
Speaker: Thomas Spengler
Title: Maintenance of Storm Tracks and Baroclinicity
Abstract: The maintenance of storm tracks and baroclinicity in the mid- and high-latitudes is a matter of ongoing debate. Using an isentropic framework, a novel diagnostic based on the tendency equation for the slope of isentropic surfaces – a measure of the potential for storm development – is presented. The tendency comprises contributions from dynamic processes, latent heat release, radiation, and sub-gridscale turbulence, which incorporates the effect of sensible heat fluxes. A climatology of these tendencies over the North Atlantic is compiled for the winters 2009 and 2010.
It is found that adiabatic tilting flattens the isentropic surfaces, reflecting the action of growing midlatitude cyclones. This tendency is climatologically balanced by the generation of slope by diabatic processes. In the lower troposphere, the most intense diabatic increase of slope is found along the oceanic frontal zone associated with the Gulf Stream and at higher latitudes in the Labrador Sea, the Nordic Seas and the Barents Sea. Latent heat release and sensible heat fluxes both contribute substantially in these regions.
A quantitative analysis of cold air outbreaks emphasises their important role for restoring the slope in the lower troposphere over the Gulf Stream region and off the sea-ice edge at high latitudes. In the upper troposphere, latent heat release due to cloud microphysical processes is the dominant mechanism maintaining the slope.
Speaker: Robert Sansom (Manchester)
Title: How fossil biases and preservation shape evolutionary interpretations
Abstract: The fossil record provides unique and powerful insight to the history of life on earth and the nature of evolutionary processes. However, the use of fossils in these contexts can be undermined by the patterns of data loss that occur during fossilization. Experiments investigating decay and decomposition of soft-tissue morphology in laboratory settings have revealed systematic biases that can cause fossil organisms to be appear more primitive than they should be, thus distorting evolutionary inferences. This is illustrated through application to the origin of vertebrates, occurring in the context of the Cambrian explosion of animals. On a broader scale, similar but subtle biases have been identified for animals with skeletons, both vertebrates and invertebrates, through meta-analysis of phylogenetic data; loss of accuracy and shift of placements occur following application of fossilization filters. By analysing the distribution of phylogenetic signal across morphological partitions (i.e. teeth and bones), further biases are found in the mammal fossil record, including our human relatives.
Speaker – Gillian Foulger (Durham)
Title: Plates vs. Plumes: A Geological Controversy
Title: Caroline Peacock (Leeds)
Title: Reactivity and Cycling of Trace-Metals in Marine Sediments
Abstract: Despite their relatively low abundance in marine sediments, iron (Fe) and manganese (Mn) minerals, through coupled sorption and redox, exert a primary control on the reactivity and cycling of trace-metals in the marine environment. Directly, these often transient minerals impart a first order effect on the concentration and stable isotope composition of metals in seawater, including nickel (Ni) and copper (Cu). Indirectly, as a result of mineral-promoted preservation of organic carbon (OC), these phases present an important but little understood link between the Earth's major and trace element cycles. In order to quantify the role of Fe and Mn minerals in global element cycles, it is necessary to understand their sorption and redox processes at the molecular level, because the precise mechanism by which trace-metals are sequestered can determine sediment-seawater exchange, and can induce significant trace-metal stable isotope fractionation, thought to control modern seawater composition for a number of micronutrients. This presentation will discuss several current research projects, where understanding the complex interplay between ferromanganese minerals and trace-metals at the molecular level has shed light on global element cycles.
19th Neil Donohue
26th Tom Mitchell: Rock mechanics/faulting
5th Kate Dobson: X-ray tomography
12th Charles Cockell: Astrobiology
19th Hartmut Boesch: Satellite measuerments of atmospheric composition
26th: Brian O'Driscoll: Scales of preservation and root causes of heterogeneities in the convecting upper mantle: an ophiolite perspective
22nd Speaker: Julia Mossinger, Nature Publishing. Title: A short presentation on the publication of research in Nature research journals
7th Speaker: Professor Andrew Meharg, Queens University Belfast. Topic: Arsenic in Rice - Latest Developments in Biogeochemical Processes and in Regulation/Policy (please note this seminar starts at 15.15)
Bastian Joachim: Halogens in the Earth's mantle
Phil Manning: Bright lights and Dinosaurs
John Broderick: Shale Gas: A Golden Age or a Gilded Cage?
Euan Nisbet: The Changing Global Methane Cycle
David Wallis Strain: Structure and strength of the Karakoram Fault, NW Himalaya, and its relationship to models of continental deformation
Burkhard Kaulich: STXM technique: Nanoscale mapping of metals and organics
Russell Garwood: Palaeontology/3D fossil reconstruction
William Peck: Magmatism and Tectonics in the Mesoproterozoic Grenville Province
Helen Talbot: Tracing aerobic methane oxidation in the geological record: calibration and application of a novel proxy
SEES postgrad conference
Chris Greenwell: Dynamic between the sheets: studying interfacial structure and reactivity in a nanogallery using simulation methods
Title: Observation-Based Research in the Met Office: Airborne and Ground-Based Studies
Abstract: Observation-Based Research (OBR) comprises two teams based at Exeter and Cardington. They share the objective of using high-quality research-grade observations to study key physical processes in the atmosphere and at the land surface. The results of these studies are used to improve the parametrization of these processes in the Met Office Unified Model, which is used for both operational weather forecasting and climate studies.
Airborne research in the Met Office goes back to the middle years of the Second World War. A brief history of some of the important milestones since that time will be given. Presently, the team at Exeter comprises groups studying cloud microphysics, aerosol and atmospheric radiative transfer. Some recent highlights of their work will be described. These will include studies of the development of ice in convective clouds, the radiative properties of biomass-burning and desert-dust aerosols and studies of the surface energy budget in semi-arid regions and the impact on land-surface temperature forecasting.
These groups are supported by a team that develops and maintains a number of unique instruments and systems. These include ISMAR (International Sub-Millimetre Airborne Radiometer), a development demonstrator for a future satellite system, and EXSCALABAR, a new system for the combined measurement of aerosol light-scattering and absorption.
Ground-based observations from Cardington have a similarly long history going back to the operation of large airships from there. Measurements from tethered balloons were extended in the 1970s to include turbulence sensors and cloud droplet measurements. New generations of these have been developed together with mast- and surface-mounted systems and can be deployed locally or on field campaigns for the study of the atmospheric boundary layer and its evolution. A particular current emphasis is on visibility and fog formation.
Title: Life on Mars: Under Pressure
Abstract: Impact ejected rocks are targets for life detection missions to Mars. The Martian subsurface is more favorable to organic preservation than the surface owing to an attenuation of radiation and physical separation from oxidising materials with increasing depth. Impact events bring materials to the surface where they may be accessed without complicated drilling procedures. On Earth, different assemblages of organic matter types are derived from varying depositional environments. Here we assess whether these different types of organic materials can survive impact events without corruption. The results suggest that the impact excavated record of potential biology on Mars will be unavoidably biased.
Title: Measurement of Ocean-Atmosphere Interactions
Abstract: About 70% of the Earth’s surface is ocean. Turbulent exchange processes at the surface are a primary control on the physical and chemical properties of both the atmospheric and oceanic boundary layers. In spite of many decades of research, the exchange processes remain poorly understood and a significant source of uncertainty in climate models. This results in part from the difficulty of making measurements over the oceans in a wide range of conditions. In this seminar I will summarise recent observational studies of surface exchange processes over both the open ocean and sea-ice, discuss some of the challenges in making the measurements, and progress in moving beyond simple wind-speed dependent parameterizations to include the impact of waves and sea-ice properties.
Speaker: Joe Keating
Title: Bone of Contention: Early Vertebrate Skeletal Evolution
Abstract: The skeleton is the definitive vertebrate organ system, yet its origin and early evolution remain poorly understood. Living vertebrates are divided into two main categories: those that possess a fully formed and fully mineralised skeleton (Gnathostomes - jawed vertebrates), and those that possess mere cartilaginous rudiments of the endoskeleton (Cyclostomes - lampreys and hagfish). This dichotomy exists because the lineages representative of intermediate steps towards the evolution of a mineralised skeleton are long extinct. Thus, if we wish to understand the origin of the vertebrate mineralised skeleton, our only recourse is the fossil record. Fortunately, there exists a plethora of Ordovician-Devonian aged armoured jawless fishes, collectively called ostracoderms, which record the piecemeal assembly of developmentally discrete skeletal modules. Importantly, they show that, while rudiments of the endoskeleton appear first in vertebrate phylogeny, it is within the dermal skeleton that mineralised skeletal tissues first appear. Consequently, the dermal armour of ostracoderms is key to elucidating the origin of vertebrate biomineralisation, and of the canonical vertebrate skeletal cell and tissue types. Here we use state-of-the-art synchrotron X-Ray tomographic Microscopy (SrXTM) to scrutinise the histology of ostracoderm skeletons at cellular level resolution. These data reveal the developmental history of the earliest vertebrate skeletons, providing a tantalising window into the origin of skeletal cell and tissue types, as well as novel phylogenetic characters for disentangling the evolutionary relationships of the earliest skeletonisng vertebrates.
Speaker: Angela Straathof
Title: Plant and soil successional stage modifies the impact of drought on rhizosphere C cycling
Abstract: Glacier forelands represent a unique successional gradient from which to study plant-soil interactions, with soils becoming richer in C, and plant communities becoming more dominated by slow-growing species with increasing distance from the retreating glacier. Using plant species and soils from early and late successional sites of the Odenwinkelkees glacier, we assessed the relative importance of plant and soil successional stage for determining ecosystem C cycling response to drought in a fully factorial greenhouse experiment. Soil dissolved organic carbon, nitrogen, and respiration rates were measured. Preliminary results show that, as hypothesised, drought reduced growth of early-successional plants most, and caused the greatest relative C loss in early-successional plant-soil systems. These results give insight into the mechanisms through which plants can modify soil C cycle response to drought, This knowledge is critical for predicting and mitigating the effects of climate change on the resistance and resilience of both natural and managed systems C cycling capacity.
Title: New directions in the study of fossil colour
Abstract: The nascent field of fossil colour has made substantial contributions to our understanding of the ecology and behaviour of ancient animals in recent years. Research to date has focussed heavily on evidence of melanin in fossil vertebrates and of structural colour in fossil insects. Despite this, the taphonomy and biology of ancient melanin is poorly resolved. Further, modern animals use diverse non-melanin pigments in integumentary colouration but the fossil record of these pigments has not been investigated. As a result our understanding of the evolutionary history of colour and its biological functions in animals is incomplete. In this seminar I will present new insights into these topics using results of recent and ongoing fossil-based and experimental taphonomic studies. In particular I will discuss new data on the taphonomy of melanin and other pigments in diverse animal tissues as revealed by electrobeam imaging and synchrotron- and mass spectrometry-based chemical analysis. These new approaches are yielding major insights into the physiology of, and the visual communication strategies used by, ancient animals, thus illuminating the evolutionary history of colour and its functions.
Title: Oxygen isotope analysis of organic matter by secondary ion mass spectrometry: Implications for the early-Earth environment
Abstract: The isotope composition of tracers such as O and Si in silicified sedimentary rocks have been used as proxies to reconstruct oceanic temperatures throughout the Earth's History. However, great controversies still remain, notably regarding possible variations of the O isotopic compositions of the oceans through time. Direct O isotope analysis of kerogens preserved in Precambrian cherts have the potential to provide crucial insight to this ongoing debate. During this seminar I will present the analytical procedure we have developed for the analysis of the O isotope composition of fossil organic matter by secondary ion mass spectrometry, and the results initially obtained on both Phanerozoic coal and kerogen samples. I will then present the results obtained on carbonaceous matter indigenous to Precambrian cherts up to ca. 3.5 Gyr-old. These new results suggest that the O isotope composition of seawater during most of the Precambrian remained around 0 ± 5‰, which is consistent with the composition of present day seawater. Combined with the chert O isotope composition record, this indicates that these cherts formed at temperatures ~50-60 °C higher than today ca. 3.5 Gyr ago in warm Precambrian oceans.
Title: Vesiculation, degassing mechanisms and crystal textures in basaltic magmas by quantitative analysis of X-ray computed microtomography images of volcanic products: examples from Italy and Vanuatu
Abstract: Basaltic volcanism is the most widespread volcanic activity on Earth. Basaltic eruptions can manifest different types of eruptive styles, from quiet lava emissions, to mild/moderate Strombolian explosions, to more violent fire fountaining events and paroxysmal activity. Understanding basaltic volcanism and its eruptive styles is therefore key to forecasting the impacts of eruptions. In this view, a series of X-ray microtomography experiments, using both synchrotron and conventional light sources, have been performed to investigate the textures of volcanic rocks in 3D with the aim to link such textures to the rheological and fluid dynamics processes that have generated them in the conduit. In this contribution, I will illustrate how vesicle and crystal textures in scoria and pumice products interact between each other to develop and increase magma permeability, promote non-explosive degassing of magmatic volatiles, and generally dictate the style of eruptive activity at basaltic volcanoes. A new, revolutionary approach to the study of basaltic volcanism, based on 4D analysis of basaltic magma kinetics, HPHT rheometry, 2D fluid dynamics and 3D numerical modelling of magma ascent and eruption, will be also illustrated in the presentation.
Title: Highly oxidized multifunctional molecules: A new class of intermediates in gas-phase chemistry and particle formation
Abstract: Highly oxidized multifunctional molecules (HOM) are low volatility multiple hydroperoxides and percarboxylic acids and they play an important role in new particle formation and SOA formation. HOM are formed during ozonolysis of terpenoids with endocyclic double bonds by autoxidation of peroxy radicals. Until recently, the autoxidation pathway had not received much attention in atmospheric chemistry.
The OH radical is the major oxidant in atmospheric photochemistry. Photooxidation by OH forms peroxy radicals by H-abstraction or addition to double bonds and OH-generated peroxy radicals also undergo autoxidation. However, HOM formation by autoxidation might compete with sequential oxidation of products by OH. To determine the importance of the autoxidation mechanism in photochemistry, we studied the OH induced formation of HOM from α-pinene and β-pinene under varying conditions ([OH], [NOX], [CO], [O2]). Experiments were performed in our continuously stirred flow reactor JPAC.