NERC Isotope Geosciences Laboratory

NIGL have secured a NERC Standard Grant in collaboration with other scientists at Nottingham University and University College London to investigate the impact of recent environmental change and anthropogenic pollution on Lake Baikal, Siberia.

Lake Baikal is the world's oldest lake in south eastern Siberia that began to form over 20 million years ago. A key feature of Lake Baikal is the high degree of biodiversity with over 2,500 flora and fauna, the majority of which are endemic. Such high levels of endemicity have led to the lake being cited as the "most outstanding example of a freshwater ecosystem" and resulted in the site being designated a World Heritage Site in 1996. Industrial development and changes in catchment land-use since the 1950's, however, pose real and serious threats to the stability of the lake's ecosystem with pollution entering the lake from major conurbations, industrial centres, mining and agricultural practises.

This project will develop the application of silicon isotope measurements in Lake Baikal to provide information on changes in biogenic nutrient utilisation in association with forcings such as: global warming, increases in water temperatures, ice cover and ice thickness.

Further information from Matt Horstwood and Melanie Leng

Congratulations to Dr Naomi Sykes (Nottingham University), Dr Jane Evans (NIGL) and Prof Alan Hoelzel (Durham):

Visit any stately home and you will find a herd of European fallow deer (Dama dama dama). These elegant animals are one of natural history's puzzles because, despite their name, they are not of European origin: they are native to Turkey from where people have gradually transported them around the globe. The distribution of fallow deer is thus a direct record of human population movements, trade and ideology with the potential to provide cultural evidence of the highest quality and relevance for a range of disciplines and audiences. There are many publications devoted to fallow deer but these largely recycle 'received wisdom'. In fact, astonishingly little is known about fallow deer; their history is obfuscated by ambiguous linguistic, textual, iconographic and archaeological evidence. To rectify this situation we carried out a pilot study, The Fallow Deer Project, whose results have challenged established theories about the species' history and provided new insights into Roman, Anglo-Saxon and Norman society. It also highlighted the scarcity of scientific work on fallow deer and demonstrated how a new dataset will enable us to explore some of the highest-profile issues in European archaeology: e.g. the nature and spread of the Neolithic in the eastern Mediterranean and the structure and worldview of societies in the Bronze Age Aegean, Iron Age Greece and Gaul, and the Roman, Byzantine, Islamic and Norman Empires.

To realise this potential, our transdisciplinary team will employ methods proven by our pilot study - e.g. the integration of archaeology, history, geography and anthropology with genetics, stable isotope analysis and osteological research - to answer the following questions:

1. Were fallow deer domesticated?
2. Under what circumstances were fallow deer established across Europe?
3. Did the collapse of the Roman Empire cause extirpation of fallow deer?
4. Did the Normans reintroduce fallow deer via Islamic influence?
5. 5) How do human-Dama relationships reveal worldview?

• For more information contact Dr Jane Evans

Thomas F.D. Mason, Dominik J. Weiss, John B. Chapman, Jamie J. Wilkinson, Svetlana G. Tessalina, Baruch Spiro, Matthew S.A. Horstwood, John Spratt, Barry J. Coles. Zn and Cu isotopic variability in the Alexandrinka volcanic-hosted massive sulphide (VHMS) ore deposit, Urals, Russia Original Research Article. Chemical Geology, Volume 221, Issues 3-4, 5 October 2005, Pages 170-187.

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The oxygen isotope composition of phosphate: a potential tool in UK freshwater studies?

High concentrations of phosphate are a primary cause of 'eutrophication' in water: an over-enrichment in nutrients leading to excessive growth of algae, which can be very damaging to the aquatic environment. Many rivers in the UK, and other parts of the world suffer from this problem because phosphate-rich waters from sewage works or from farming activities are pumped or drain into the rivers. Dealing with this problem involves knowing where the phosphate comes from, and understanding what happens to it when it gets into the river.

The project is headed by Tim Heaton (NIGL), with Daren Gooddy and Dan Lapworth (BGS), and Roland Bol and Steve Granger (Rothamsted Research).

The phosphate ion contains oxygen atoms which can be of different isotope types: oxygen of atomic mass 18 and oxygen of atomic mass 16 (both are naturally-occurring, non-radioactive isotopes). Preliminary studies have shown that the proportions of these two isotopes differ depending on where the phosphate came from (e.g. sewage compared with agricultural fertilizer), and that changes in the proportion of the two isotopes indicate the way in which the phosphate is being used in the water. However, this preliminary work has been mainly done in saline waters in estuaries and coastal areas, and we want to see if it might work in fresh water environments in the UK.

The plan is therefore two-fold:

1. to analyse the proportions of oxygen-18 and oxygen-16 in phosphate from a small number of sewage and agricultural effluents, to see if they differ. If they do, we may be able to use such measurements to determine where phosphate pollution is coming from
2. to see if the proportions of oxygen-18 and oxygen-16 in phosphate coming from a point-source (e.g. the outfall of a sewage works) change as the phosphate is carried downstream. If they do, we may be able to use such measurements to determine the phosphorus demand or 'limitation' of the system — an important factor in controlling eutrophication.

Bering Sea diatom isotope records during the onset of Northern Hemisphere Glaciation

The progressive advancement of ice-sheets across the Northern Hemisphere in the late Pliocene and the development of glacial-interglacial cycles which punctuate the Quaternary marks a significant threshold in the Earth's climate history. Of particular note are the transitions associated with the onset of major Northern Hemisphere Glaciation (NHG), c. 2.85-2.73 Ma, when large ice-sheets developed across Greenland, Eurasia and Northern America. This project aims to investigate the nature of these changes in the Bering Sea by measuring diatom δ¹³C, δ¹⁸O and δ³⁰Si from 3.2-2.5 Ma at IODP Site U1341. Situated south of the sea-ice extent at the western flank of Bowers Ridge, the results will permit an assessment of linkages between the Pacific Ocean and Bering Sea with regards to meltwater influx and the biological pump.

Establishing an understanding of the latter is critical for determining the role of the oceans in regulating atmosphere CO₂ concentrations over this time-frame.

This project is headed by George Swann (NIGL) and includes Andrea Snelling (NIGL) and Jenny Pike (Cardiff).

Congratulations to Randy for being awarded the Murchison Medal by the Geological Society of London. The Murchison Medal is awarded to people who have made a significant contribution to science by means of a substantial body of research. Council looks at breadth as well as depth in pure and applied hard rock science.

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The Svalbard exemplar of Neoproterozoic glaciation

Although life successfully moderates surface conditions on Earth, some events in Earth History have threatened the viability of most life forms. Arguably the most profound and long-lasting challenge in the last 2 billion years was glaciation on a near-global scale, with the best documented event being around 650 to 630 million years ago ("Marinoan" glaciation). The Snowball Earth hypothesis proposes that snow and ice became so widespread that the Earth become much more reflective of solar radiation and cooled to a mean temperature of around -50 degrees Celsius. Glaciation was eventually terminated by the build-up of carbon dioxide emitted from volcanoes, that was not used up by the weathering of rocks since rocks were buried beneath the extensive snow and ice cover. Almost all facets of the Snowball Earth hypothesis, and of alternative hypotheses, are open to challenge, there is general agreement that glaciation reached tropical latitudes at sea level.

New lines of evidence are needed to refresh the debates and constrain future modelling efforts.

• More information

This project is headed by Ian Fairchild (Birmingham) and includes Dan Condon (NIGL) as a Co-I.

Terrestrial Holocene climate variability on the Antarctic Peninsula

The Antarctic continent is an important part of the Earth system, both influencing and responding to global ocean and atmospheric circulation. A key question in understanding and attribution of Antarctic climate change is whether the recorded changes on the Peninsula are unusual compared with past natural climate variability. Moss banks are ideal deposits for reconstructing climate change over the land surface of the Antarctic Peninsula because of their location in relation to recorded temperature changes, their age, and their attributes as archives.

The moss banks have accumulated peat over the past 5-6000 years at locations throughout the western Antarctic Peninsula. They are formed of only one or two species, annual growth can be traced in the surface peats and preservation of moss remains is good. We will use multi-proxy indicators of past climate (stable isotopes, measures of decay, testate amoebae and moss morphology) to reconstruct climate variability from critical locations across the observed gradient in rate of temperature change between 69o and 61o S.

This project is headed by Dan Charman (Exeter) with Melanie Leng (NIGL) as a project partner.

This new project, in association with The Climatological Observers Link (COL) and other selected rainfall observation stations, aims to map the variability in oxygen and hydrogen isotopes in UK rainfall initially over a series of rainfall events in March 2010. The project is being run by Dr Matt Jones (Nottingham), Dr Jon Tyler (Oxford) and Prof Melanie Leng (NIGL).

• A video and web page are available, for more information

Dating the "Taung Child" Australopithecus africanus type specimen through U-Pb measurements of associated calcite crystals

The "Taung Child" was found in 1924 at the Buxton limestone quarry, Northwestern Province, South Africa. The "Taung Child" was the first early hominid found in Africa and became the type specimen of Australopithecus africanus. Mining activities continued at the quarry and the geological context of the specimen was lost, hampering attempts to date the hominid and understand its ecological context. Because of this, current estimates for the age of the "Taung Child" range from 3 million to 1 million years old. Such chronological uncertainty greatly hampers our understanding of early hominid evolution in Africa. We propose to take samples of calcite crystals attached to the endocast of the "Taung Child" and other associated fossils for uranium-lead dating using state-of-the-art facilities at the NERC Isotope Geosciences Laboratory. Pilot evidence demonstrates the suitability of such calcite crystals for high-precision age determination, and permission to sample the calcites has been granted by the Hominid Access Committee.

The proposed radiometric dates for the "Taung Child" are likely to alter the current age-range for Australopithicus africanus, perhaps changing our understanding of ancestor-decendant relationships among early hominin species.

The methods undertaken in this study can be applied to other early hominin specimens from the "Cradle of Humankind" World Heritage Site, South Africa, thereby improving the chronology of human evolution in Africa, and the methods will be refined to maximize the scientific information obtained from the minimum use of valuable fossil material, thereby improving generic methods of analysis of rare and invaluable museum collections.

This project is headed by Prof Randy Parrish (NIGL), with Dr Philip Hopley, Birkbeck College London; Dr Colin Mentor, University of Johannesburg; and Dr Bernhard Zipfel, University of the Witwatersrand.

Critically testing the role of δ³⁰Si (diatom) as a novel productivity signal in temperate lakes.

Despite occupying only ~3% of the earth's land surface, lakes are productivity hotspots and play an important role in the biological fixing, mineralisation and burial (collectively cycling) of carbon, at both a landscape and global scale. Lakes are sensitive to environmental change, yet the ways that lake ecosystems respond (in terms of their overall structure, and processes such as lake productivity) are poorly understood. A NERC-funded project aims to characterise the seasonal dynamics of silicon and δ³⁰Si and link these to diatom productivity in an eutrophic, freshwater lake (Rostherne Mere, Cheshire, UK) to test critically the use of δ³⁰Si_diatom as a productivity proxy in freshwater systems. New analytical developments also make it possible to measure δ¹⁸O in diatom silica from the same samples, thus providing the opportunity to link δ³⁰Si and diatom productivity to climatic and hydrological variability. We will monitor bulk sediment formation, planktonic diatom dynamics, climate, hydrology and lake function (stratification) over an 18-month period (including two spring seasons) at high resolution by means of automatic traps, automatic water sampler, on-lake weather station, and a thermistor chain.

The team of researchers include: Dr David Ryves (Loughborough University), Dr Jon Tyler (Oxford University) and Prof Melanie Leng (NIGL) and Dr Phillip Barker (Lancaster University).

Congratulations to Professor Randy Parrish who has been awarded the 2010 Schlumberger Medal of the Mineralogical Society.

This annual award was founded in 1990 through the generous sponsorship of Schlumberger Cambridge Research and has the purpose: To recognize scientific excellence in mineralogy and its applications; mineralogy being broadly defined and reflecting the diverse and worldwide interests and membership of the Society with its various specialist groups. Evidence of such excellence should be in the form of published work by a currently active scientist. Professor Parrish will be presented with this award at the 44th Annual conference of the Volcanic and Magmatic Studies Group in Glasgow in January 2010.