Wednesday October 7th 2009

Glimpses of the Palaeolithic in the Midlands

Dr Lynden Cooper,

Department Archaeology, University of Leicester

Abstract

Recent fieldwork by University of Leicester Archaeological Services has revealed several Palaeolithic sites that have helped filled a lacuna in the prehistory of the region. Brooksby Quarry has yielded artefacts from Cromerian deposits – the lost Bytham river that once drained Wales and the English Midlands. The Bytham valley is now seen as the colonisation route for the first humans (Homo heidelbergensis) to reach Britain c 500 – 700,000 years ago. A housing development in Glaston, Rutland led to the discovery of a mid-Pleistocene hunting station and hyaena den. The lithic assemblage included leaf-points, a diagnostic weapon head of the Earlier Upper Palaeolithic from c 35,000 years ago. It is suggested that the lithic technology represents the work of the last Neanderthals. The site was preserved in a graben structure on the crest of a hill, and represents a new type of site formation process that might be anticipated at other sites where similar geological and topographical conditions can be found. A Magdalenian (Creswellian) site at Bradgate Park revealed rare evidence for an open-air site, complementing the better known assemblages from caves sites on the English Karst.. The humans were the first to return to the North-west European peninsula at the end of the Last Glacial Maximum, c 15,000 years ago. Finally, a Terminal Palaeolithic site at Launde, Leicestershire represents the people who re-colonised the region following the Younger Dryas stadial at c 11,000 years ago.

Wednesday 21st October 2009

What can living brachiopods tell a palaeontologist?

Abstract

Brachiopods  are recognised as important components of shallow marine faunas during the Palaeozoic where they are diverse and abundant.  However, following the P/T mass extinction they are often portrayed as ‘Nature’s losers’;  weedy, slow growing, trapped in refugia, so rare that most marine biologists do not encounter them and so unappetising that nothing will even bother to eat them.  But is that fair?

Mixed assemblage of living brachiopods living attached to the steep fjord sides of Doubtful Sound, New Zealand (Photo: Mike Barker)

Recently I, along with colleagues in New Zealand and the British Antarctic Survey, have been studying  the ecology and life history of a range of living brachiopods. Our aim is not just to understand more about these fascinating but little known animals but also to try to shed light on to their evolutionary history and fossil record.

Wednesday 4th November 2009

Rebuilding Afghanistan through Geoscience

Abstract

This talk summarises a 5 year experience with Afghanistan between 2003 and 2008. Afghanistan is rarely out of the media and attracts a lot of interest from the general public and politicians alike. Most of the news is about war, death, drugs and poverty. Whilst it is true to say that the Afghan experience since the invasion of Soviet troops in 1979 has been a heart-rendering tragedy characterised by invasion, ethnic war and fundamentalism, this is only part of the story. Afghanistan has a very long and rich history and its position at the crossroads of East and West has left indelible strands in its national character. The presenter first visited Kabul in early 2003 working directly with the Afghan Government, including senior Ministers and advisers to President Karzai and generated a collaborative project funded by UK Aid aimed at strengthening the Afghan Geological Survey, re-modelling a vast array of data and attracting international mining investment with the aim of moving Afghanistan towards a peaceful economy. Afghanistan comprises a number of Precambrian – Recent, Laurasian and Gondwanan terranes that finally coalesced in the Mesozoic and Tertiary. It remains at the very heart of the modern Himalayan orogenic event with the western edge of the Indian plate cutting the eastern part of the country. Afghanistan hosts a large number of important mineral deposits including copper, gold, iron, and the famous lapus lazuli that was traded with the Pharaohs of Ancient Egypt. The presentation will attempt to roll together the varying themes of mineralisation, geotectonics, economic development, and post-conflict issues and show how geosciences can help, in a very practical way, to rebuild a shattered country.

Wednesday 18th November 2009

Permian extinctions

Abstract

The mass extinction of the dinosaurs is famously associated with a giant meteorite impact. However, it also coincides with a vast outpouring of lava in the Deccan region of India and for other mass extinction events it is this volcanic phenomenon, not impact, that is always contemporaneous. The end-Permian mass extinction is the greatest crisis in the history of life. For the past two decades it has been known to precisely coincide with the eruption of the Siberian Traps – one of the largest of all the giant flood basalt provinces. Extinction models seek to find a link between these two phenomena. Less well known is the fact that the end-Permian mass extinction was preceded by an crisis in the Middle Permian, approximately 8 million years earlier, in which flood basalt volcanism again figures. The flood basalts in this case erupted in SW China and are known as the Emeishan Province. The lavas are interbedded with shallow marine limestones that contain an excellent record of Middle Permian fossils. It has thus been possible to examine both the volcanism and the extinction event in the same locations in SW China. This talk will look at the evidence from SW China, suggest an extinction mechanism involving explosive volcanism and compare this with the latest ideas for the end-Permian (and other) mass extinction events of the fossil record.

Monday 30th November 2009

Parent Body Lecture, New Walk Museum, Leicester

Life and Earth: interlocking histories

Life and the Earth have had interlocking histories for approaching 4 billion years - most of the life of the Solar System. For biologists it was Darwin in 1859 who first provided us with a general theory of life's evolutionary processes although inevitably there were then huge gaps in the detail. Earth Science had to wait about a century more before we had an equivalent general theory of our planet's history and dynamic processes. Now that we have a full picture the interelationships become clear. As James Lovelock has put it, Earth supports life and life supports Earth, or I would rather say, affects the Earth, although in profound ways. Life has had to withstand several major catastrophes over the past 800 million years (when complex life forms have been in existence) but - so far - has recovered although not always in its original pattern. I shall give a number of examples and use them to discuss the ways in which the earth sciences and biological sciences must be seen as a unity if our species is to survive in a tolerable fashion.

Wednesday 2nd December 2009

West Greenland: Arcs and Crustal Growth in the Early Earth

Professor Brian Windley

Abstract

How did the crust of the Earth develop 3000 million years ago? Did it involve plate tectonic processes or not? Today between the fjords, mountains, glaciers and icecaps in West Greenland we see a spectacularly exposed terrane, which reveals several remarkable cross-sections through 3000 my-old crust of the earth. The evolution started with island arcs, passed to Andean-type, active continental margins, and finished with collisions between crustal blocks. Oh, and the mountains have been eroded down to their roots, so we are looking at the deep crust.

Wednesday 13th January 2010

The Earth after us

Dr Jan Zalasiewicz

Department of Geology, University of Leicester

Abstract

The Earth’s history is a 4.6 billion narrative that can be teased out, forensically, by the geologist from myriad clues preserved in the strata of this planet.  It is a story of glaciations and global greenhouses, of the rise and destruction of mountain belts, of the evolution of life-forms both enigmatic - as the Charnia fauna,  say – and familiar.  But what position can the brief history of humans have within this almost unimaginably long narrative?  This talk will consider the evidence, and the story, that might emerge as alien visitors explore the Earth, one hundred million years in the future.

Wednesday 27th January 2010

Observing Earth's ice sheets from space.

Abstract

After a century of polar exploration, the past decade of satellite measurements have painted an altogether new picture of how Earth’s ice sheets are changing. As global temperatures have risen, so too have rates of snowfall, ice melting, and glacier flow. While, regionally, the balance between these opposing processes has varied considerably, a body of data show that Antarctica and Greenland are each losing mass overall. Our best estimate of their combined imbalance is 0.5 mm/yr. While only a modest contribution to present sea level rise of 3.0 mm/yr, the losses in Antarctica and Greenland are the result of increased ice discharges that have doubled in the past decade. In both continents there are suspected triggers for the accelerated ice discharge - surface and ocean warming, respectively - and, over the 21st century, these processes could rapidly militate against the snowfall gains predicted by present coupled climate models.

Wednesday 10th February 2010

The Genesis and Evolution of Sulphate Evaporites in the Midlands

Abstract

Evaporites not only provide information about past climates, but also because they are chemically very mobile, present a record of the changes they have undergone through geological time. These changes very often hinder sedimentological interpretation but provide valuable evidence about the effects of diagenetic, metamorphic and hydrogeological processes. Evaporites are economically important industrial minerals and are essential sources of raw materials for not only manufacturing a wide range of goods but also to sustain life. The United Kingdom is fortunate to have World Class evaporite resources the most important of which formed during the Triassic Period. Triassic rocks underlie most of the Midlands and contain the most important of the sulphate evaporite deposits, gypsum and anhydrite. It is rare to be able to see evaporites exposed at the surface and this has limited the geological study of these interesting rocks. However because of the widespread underground mining and associated activity particularly in the East Midlands a significant amount of geological evidence is available. A synthesis shows that the sulphate evaporites experienced a common history and were deposited as gypsum and anhydrite in a sabkha environment in a series of cycles, notably the Tutbury and Newark. They have subsequently undergone conversion to anhydrite during burial followed by reconversion to gypsum during Tertiary uplift. This process has induced diapirism and created metamorphic changes sometimes producing foliated sulphate rocks. The latter have become the source of some of the attractive alabasters for which the Trent Valley is famous.

Wednesday 10th March 2010

Arsenic mining: Environmental monitoring using earthworms, toenails and a simulated stomach.

Abstract

This research details a multidisciplinary assessment of arsenic contaminated soils in terms of human exposure and environmental toxicology. Two species of earthworm (Lumbricus rubellus and Dendrodrillus rubidus) along with their host soils and excreta (casts) were collected from 24 locations at Devon Great Consols (DGC), a former arsenic mine located in the Tavistock district of Devon, UK. Total arsenic in these samples was determined via ICP-MS. The bioaccumulation of arsenic in DGC earthworms was found to be comparable to the human bioaccessible fraction of arsenic in the host soils, estimated using a physiology-based extraction test (PBET), suggesting earthworms and PBETs might be used in conjunction when assessing risk at contaminated sites. Earthworms at DGC appear to be highly resistant to arsenic toxicity. The Comet Assay revealed DNA damage levels in earthworms native to DGC were comparable to background levels in earthworms from uncontaminated sites. Non-native earthworms exposed to a contaminated DGC soil incurred high levels of DNA damage, highlighting the potential toxicity of contaminated DGC soils. Arsenic biotransformation in DGC earthworms was investigated using HPLC-ICP-MS to investigate the mechanisms by which these earthworms mitigate arsenic toxicity. Whilst toxic inorganic arsenic was transformed to less toxic organic species, the degree of transformation was limited and not related to soil total arsenic levels, suggesting this mechanism is not involved in mitigating toxicity. Human toenail samples from DGC residents were investigated as a biomarker of exposure to elevated environmental arsenic and demonstrated significantly higher levels of arsenic than a control group. These findings highlight the potential for human exposure to arsenic at contaminated sites in the southwest UK, where mining activity has led to widespread environmental arsenic contamination.

Wednesday 24th March 2010

Managing our flood defences for the future

Abstract

I will take a philosophical look at how we are managing and maintaining our existing flood defences, and planning and constructing new flood defence schemes for the protection of land for our future generations. This will be discussed by using a number of case studies, for example, the Ely Ouse Lodes Strategy, which assessed the stability of the earth embankments under current maintenance regimes and the impact of potential changes in ground and groundwater conditions, and plans for tidal barriers along our shores.