Seminars

The Department hosts a variety of seminars to discuss research results at different levels. However, everyone is invited, so please come along!

Departmental Research Seminars 2016/17

Departmental research seminars are held every Thursday 1pm - 2pm in G67 (Teaching Area 3), Bennett Building. Both external and internal speakers present the latest results of their research.

Semester 2

DateSpeakerTitle and Abstract
19th January 2017 Dr Alex Wolfe
University of Alberta

Exceptional polar amplification of middle Eocene climate under modest greenhouse-gas forcing and possible implications for the future.

Eocene palaeoclimates provide partial analogs for the future with respect to equilibrium responses to higher-than-present atmospheric CO2. Parallel temperature and CO2 reconstructions from middle Eocene terrestrial sediments that infill a kimberlite diatreme in subarctic Canada enable detailed assessments of regional climate sensitivity for the interval immediately post-dating 38 Mya. These sediments have exceptional preservation of botanical fossils, revealing a humid-temperate forest ecosystem with abundant Metasequoia (dawn redwood). Pollen assemblages and oxygen stable isotopes from wood cellulose indicate mean annual temperatures (MATs) at least 17 ˚C warmer than present, and coldest months more than 25 ˚C. Stomatal indices from Metasequoia foliage constrain atmospheric CO2 to 450-1000 ppm, with a median of 630 ppm. The reconstructed MATs are ~10˚C warmer than predicted by a global Earth system sensitivity of 6˚C per CO2 doubling, demonstrating that exceptional polar amplification characterized middle Eocene climates even in absence of cryospheric influences (i.e. coldest months consistently >0˚C). Fundamental changes to synoptic circulation may explain the inferred magnitude of high-latitude warming and concomitant increase of precipitation, for which direct analogies exist in contemporary global warming: deepening lows and enhanced cyclogenesis over the Arctic Ocean, slowing of the polar jet stream, and widening of Hadley cells. Altered circulation patterns during greenhouse climate states may explain why climate models have difficulty capturing fully the conditions implied by proxies under moderate (<1000 ppm) CO2 concentrations.

26th January 2017
Dr Mick Whelan
University of Leicester

Beyond the drain: Chasing household chemicals in aquatic environments

Few of us ever think about what happens to the chemicals in our shampoo as it washes down the drain, where the water from our washing machines goes as we peg out our clothes or whether the pain killer we took this morning will have ecological impacts long after our hangover has subsided. Like the waste water from our toilets, these chemicals find their way into municipal sewers and are processed by thousands of sewage treatment works dotted across the landscape. Although modern sewage works are very good at removing pollutants from waste water, a fraction of the chemicals used in household products and pharmaceuticals are emitted to rivers and streams in the treated effluent. In countries where there is poor sewage treatment, waste water can be discharged directly to water courses, where the resulting concentrations of constituent pollutants can be very high. In either case, it is important to assess the potential of so-called “down-the-drain” chemicals to do harm to the organisms living in receiving water bodies. In this seminar Dr Whelan will discuss the fate of these chemicals in aquatic systems, illustrated with some specific examples and focussing on a class of chemicals called volatile methyl siloxanes which have some interesting properties and which are still not entirely understood.

2nd February 2017 Dr Julie Prytulak
Imperial College London

Stable Thallium Isotope Variations in Magmatic Rocks

Thallium is one of the heaviest naturally occurring elements and very little stable isotope fractionation between its two isotopes (203Tl and 205Tl) is predicted by classical theoretical calculations. However, due the its large nucleus, an analytically significant range of isotope compositions spanning over 35 epsilon units has been documented in natural samples. Low temperature environments have, by far, the largest isotope variations in nature.  Dr Prytulak will give an overview of this little explored element and its underlying isotope systematics and then explore the use of thallium elemental abundances and isotope compositions to investigate mantle heterogeneity and recycling processes in subduction zones. This aims to demonstrate that the unique chemical properties and low natural abundance of thallium, coupled with its extreme isotope fractionation, make it an ideal tracer of recycling processes in the solid Earth.

16th February 2017 Dr Hannah Hughes
Camborne School of Mines

Metallogeny of the mantle - xenoliths and diamonds

Hannah’s research aims to understand the sources and budget of metals and sulphur spatially and through time to assess how this influences mineralisation in the crust. She does this by studying the controls on platinum-group element (PGE), chalcophile element and semi-metal (often classed as ‘critical’ and/or precious metals) mobility in the mantle, particularly the lithospheric (upper) mantle. These elements are intimately linked with the mobility of sulphur, often present as sulphide minerals, through the processes of partial melting and metasomatism. Mantle xenoliths and sulphide inclusions in diamonds can be used as direct insights into the abundance of these elements at depth.

By linking these xenolith and diamond inclusion observations with the regional metallic fingerprints of large igneous provinces (LIP) and other magmatic rocks at the Earth’s surface, an assessment can be made for how the metal basket of some ore deposits, such as Ni-Cu- PGE mineralisation, may be controlled by previous tectonic events (or ‘preconditioned’). For example, this preconditioning may have the ability to change precious metal ratios (e.g., Pt vs. Pd) in mantle-derived magmas, and thereby change the metal basket of subsequent mineral deposits.

23rd February 2017
Dr David Reynolds
University of Cardiff

Reading between the lines: what long lived clams can tell us about past climate variability.

Our understanding of past marine variability is largely limited by the lack of long-term baseline records. The generation of robustly calibrated and precisely dated proxy archives are therefore required to investigate the natural mechanisms and forcings that drive marine variability, and to assess the influence of marine variability on the wider climate system. Palaeoceanographic reconstructions constructed by analysing the growth history and isotopic composition of long-lived marine bivalves such as Arctica islandica from the North Atlantic region, can provide absolutely dated and robustly calibrated baseline records of past marine variability extending back over the past millennium. The annual resolution and absolute dating precision of these records, due to the application of statistical techniques derived from dendrochronology, facilitate the quantification of past marine variability, the evaluation of the influence of solar and volcanic and volcanic activity on North Atlantic climate and ultimately assess the role marine variability plays on driving atmospheric climate variability over the last millennium.

2nd March 2017
Professor Jo Morgan
(IODP Expedition 364 Co-chief) Imperial College London

IODP-ICDP Expedition 364: Drilling the peak ring of the Chicxulub impact structure

In 2016 a joint IODP-ICDP expedition drilled the peak ring within the Chicxulub impact structure in Mexico. The aims of  Expedition 364 were to investigate: (1) the nature and formational mechanism of peak rings, (2) how rocks are weakened during large impacts, (3) the nature and extent of postimpact hydrothermal circulation, (4) the deep biosphere and habitability of the peak ring, and (5) the recovery of life in a potentially, sterile zone. Other key targets included: sampling the transition through a rare midlatitude section that might include Eocene and Paleocene hyperthermals and/or the Paleocene/Eocene Thermal Maximum (PETM), and any observations from the core that may help us constrain the volume of dust and climatically active gases released into the stratosphere by this impact.

Core was recovered between 505.70 and 1334.73 mbsf, and included: ~110 m of Eocene and Paleocene sedimentary rocks, ~130 m of suevite (impact breccia) and clast-poor impact melt rock, and ~590 m of uplifted, highly-fractured and shocked granitic basement rocks.  There was excellent core recovery, and the recovered core and wireline logs are of excellent quality. Peak-ring formation was a topic of a recently published article, and progress has been made on several of the other goals.  Currently, Professor Morgan uses high-resolution velocity models obtained from full-waveform inversions to map the thickness of the suevite layer and top of felsic basement across the peak ring, and track the suevite away from the borehole into the surrounding annular trough and central basin.

9th March 2017

Mr Holger Kessler
BGS

CANCELLED

3D Geological Modelling at the British Geological Survey: Principles, applications and future developments.

16th March 2017

Dr Rex Taylor
University of Southampton

Tenerife volcanic activity: controlled by a pulsing plume?

Upwelling plumes bring a diverse range of deep mantle compositions from long-term storage to the Earth’s surface, but the scale and origin of these materials is questionable. We investigate the changes in mantle composition emerging from a plume through a period of 2 million years. Examining the sequence of felsic pyroclastic rocks from Tenerife in the Canary Islands has enabled us to determine time-integrated magma compositions at ~30 ka intervals. These reveal progressive, coordinated changes in lead isotope ratios and aluminium content on a timescale of 2 Ma. Lead isotopes reflect time-integrated Th-U-Pb variation in the mantle while aluminium responds to feldspar crystallisation and magma water content. The surprising correlation between these parameters indicates that the mantle plume pulsates between wetter U-rich and dryer U-poor phases. Such pulses are interpreted to reflect 50-100 km swirls of ocean crust entwined in oceanic lithospheric mantle following subduction recycling and storage in the deep mantle.

18th May 2017 Cheryl Haidon
University of Leicester

Our XRD – capabilities and possibilities
Powder Diffraction in the College of Science and Engineering

25th May 2017
Dr Saskia Goes
Imperial College London

Sink or stall: subduction-transition zone dynamics

Semester 1

DateSpeakerTitle
6th October 2016
Prof Colin Waters
BGS / Honorary Professor
University of Leicester

Are we living in a new epoch: the Anthropocene? An update on latest working group recommendations

13th October 2016 
Dr Andy Carr
University of Leicester

From dunes, to plant biomarkers, to fossiled urine: some Quaternary palaeoenvironmental research highlights from Geography

20th October 2016 
Dr Arnoud Boom
University of Leicester

Environmental Reconstruction using stable isotopes and organic geochemistry

27th October 2016
Dr Rob Duller
University of Liverpool

"What's that coming over the hill?"
The 1918 jökulhlaup, southern Iceland

3rd November 2016

Dr Juan Carlos Berrio
University of Leicester

Sub-millennial scale climatic and environmental changes since middle Pleistocene from Fúquene basin in Colombia

10th November 2016
Dr Kate Dobson
NERC independent Research Fellow
Durham University

Taking Geoscience to the IMAX - seeing the unseeable using X-ray tomography

17th November 2016
Dr Joerg Kaduk
University of Leicester

JULES
The joint UK land environment simulator

24th November 2016
Professor Simon Poulton
University of Leeds

Anoxia in Modern Sediments

1st December 2016
Dr Mark Powell
University of Leicester
Sediments and sediment transport in alluvial rivers: an overview of research.

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