SERVICES & FACILITIES ANNUAL REPORT - FY April 2003 to March 2004

SERVICE: Open University Uranium
Series Facility, OUUSF / FUNDING:
Block / AGREEMENT
F14/G6/47 / ESTABLISHED as S&F
1998 / TERM
3 year
TYPE OF SERVICE PROVIDED:
The purpose of OUUSF is scientific research in environmental sciences and science-based archaeology using Uranium-series methodologies. Original investigations are carried out in collaboration with NERC stakeholders in the pursuit of knowledge and better understanding of the Earth system. U-series analyses are an essential component of research projects in Earth and environmental science, oceanography, hydrology and science-based archaeology. Topics include magma chamber evolution and volcanic hazard prediction, global climatic change through dating of authigenic carbonate deposits, and human evolution through dating of bone, and the study of groundwater evolution
OUUSF provides state-of-the-art U-series isotope preparation labs, a high abundance sensitivity Finnigan MAT 262 solid source mass spectrometer, a Nu Instruments plasma ionisation mass spectrometer and a New Wave Excimer laser ablation system.
OUUSF provides the equivalent of one user-year of training and analyses per annum, which represents 25% of Open University Isotope Geochemistry Laboratory capacity and corresponds to circa 165 project samples. Quality Assurance is maintained through the repeated analysis of internal standards and Certified Reference Materials, reagent and total-procedure blanks and calibrations, performed by staff and users, equivalent to some 30 samples per year.
Users should have, or be prepared to learn at the OUUSF, the analytical skills necessary for successful processing of samples in a clean room, for working with radioactive materials, and for using isotope ratio mass spectrometers. OUIGL and OUUSF staff are primarily involved in supervision of post-graduates and have limited capacity to perform analyses for collaborators.
Scientific results of collaborative research may be included in PhD thesis or published in scientific journals or disseminated in electronic media.
Scores at Last Review (each out of 5) / Date of Last Review:
Need / Uniqueness / Quality of Service / Quality of Science & Training / Average
4 / 4.5 / 4.5 / 4.5 / 4.38
CAPACITY of HOST ENTITY
FUNDED by S&F / Staff & Status / Next Review (January) / Contract Ends
(31 March)
Dr P van Calsteren, Senior Research Fellow: 0%
Dr M A Gilmour, Project Officer: 0%
25 % / Dr L E Thomas, Project Officer: 100% (from 1 August ‘04)
Grade E Technician, 50% vacancy / 2006 / 2007
FINANCIAL DETAILS: CURRENT FY
Recurrent Allocation £k / Unit Cost £k / Capital Expend £k / Income
£k / Full cash cost £k
Unit 1
/
Unit 2
/
Unit 3
92.4 / .56 / 0.00 / 0.00
FINANCIAL COMMITMENT (by year until end of current agreement)
2003-04 / 83.3 / 2004-05 / 84.5 / 2005-06 / 85.3 / 2006-07 / TBD / 2007-08 / TBD
STEERING COMMITTEE / Independent Members / Meetings per annum / Other S&F Overseen
Isotope Geoscience Facilities / 15 (Chair:Prof Harris OU) / 2 / NIGL, AIF, ICSF
APPLICATIONS: DISTRIBUTION OF GRADES (Current FY — 2003/04)
a5 / a4 / a3 / a2 / a1 / b / R*/Pilot / Reject
NERC Grant projects
Other academic / 1 / 1
Students / 1 / 2 / 1
Pilot
TOTAL / 2 / 2 / 2
APPLICATIONS: DISTRIBUTION OF GRADES (per annum average previous 3 years —2000/2001, 2001/2002 & 2002/2003)
a5 / a4 / a3 / a2 / a1 / b / R*/Pilot / Reject
NERC Grant projects / .33 / .33
Other Academic / .67 / .67 / .33
Students / .33 / 1.33 / .33
Pilot
TOTAL / 1.33 / 2.33 / .66
PROJECTS COMPLETED (Current FY)
a5 / a4 / a3 / a2 / a1 / b / R*/Pilot
NERC Grant projects / 2
Other Academic / 1 / 2
Students / 1
Pilot
USER PROFILE (current FY) / *Combined non-Thematic and Thematic

Grand

Total

/ Infrastructure /

PAYG

Supplement to NERC Grant * / Student / NERC C/S / Other / NERC Grant* / Student / NERC C/S / Other
Total / NERC / Total / NERC
6 / 4 / 1 / 2
USER PROFILE (per annum average previous 3 years) / *Combined non-Thematic and Thematic

Grand

Total

/ Infrastructure /

PAYG

Supplement to NERC Grant * / Student / NERC C/S / Other / NERC Grant* / Student / NERC C/S / Other
Total / NERC / Total / NERC
4.33 / .67 / 2 / .67 / 1.67
USER PROFILE (current FY)
Academic / Centre/Survey / NERC Fellows / PhD / Commercial
2 / 4
USER PROFILE (per annum average previous 3 years)
Academic / Centre/Survey / NERC Fellows / PhD / Commercial
2.33 / 2
OUTPUT & PERFORMANCE MEASURES (current FY)
Publications (by science area & type)
SBA / ES / MS / AS / TFS / EO / Polar / Grand Total / Refereed / Non-Ref/ Conf Proc / PhD Theses
3 / 4 / 7 / 7
Distribution of Projects (by science areas)
SBA / ES / MS / AS / TFS / EO / Polar
1 / 5
OUTPUT & PERFORMANCE MEASURES (per annum average previous 3 years)
Publications (by science area & type)
SBA / ES / MS / AS / TFS / EO / Polar / Grand Total / Refereed / Non-Ref/ Conf Proc / PhD Theses
2.33 / 3 / 5.33 / 5.33
Distribution of Projects (by science areas)
SBA / ES / MS / AS / TFS / EO / Polar
.67 / 3.67
OVERVIEW & ACTIVITIES IN FINANCIAL YEAR (2003/04):
During this report year 12 projects graded a3high to a4, on average, were active. Two projects form part of a PhD project and post-graduates received extensive training at the OUUSF. Seven papers involving OUUSF staff or data were published in peer-reviewed journals, 2 of which in Nature.
The MAT 262 mass spectrometer has been performing well, considering its age. Some of the electronic circuits and the software are decidedly dated and replacement should be considered within the next three year. The Nu-instruments Multi-Collector Plasma Ionisation Mass Spectrometer has been available for OUUSF work throughout and the New Wave Excimer laser ablation system is being tested for high-resolution work. Chemical dissolutions and separations have been carried out in custom-designed perspex containment boxes of our ‘Picotrace’ suite. Some improvements to these facilities will be carried out in the near future.
In a multi-user, multi-project laboratory it is essential to maintain high levels of Quality Control and 14 whole-rock standards have been analysed for this purpose. Moreover, analyses have been carried out on 111 shelf standards and Certified Reference Materials to ascertain instrument performance standards, as well as 116 reagent and procedure blanks to check chemical procedures.
Scientific highlights this year include:
Timescales in young magma systems; a case study from Damavand Volcano, N Iran (IP/694/0301)
Comparison of U-series ages with (U-Th)/He apatite ages at Damavand Volcano Iran. Damavand Volcano, Alborz Mountains, N. Iran is an isolated voluminous (>400km3) composite volcano, built from small-volume eruptions of trachyandesite. The stratigraphy has been calibrated using Ar-Ar and (U-Th)/He apatite dating to establish a broad volcanic history. Eruptions as young as 7,000 yrs and as old as 445,000 years bracket activity at Damavand. The lavas and pyroclastic deposits are uniformly porphyritic (fspr + oxide + apatite + px ± amph ± bi), representing a very restricted compositional range (57-63% SiO2). The ubiquitous presence of large apatite crystals has allows comparison of potential crystallization ages with those of eruption. Apatite strongly concentrates Th, leading to low U/Th ratios compared with the magmas from which they crystallize. By analyzing the (230Th/232Th) and (238U/232Th) activity ratios of coexisting apatite-whole rock pairs 2-point isochrons can generated, which, in the case of simple closed-system crystallization, should represent the age of apatite crystallization. These ages can then be compared with ages from (U-Th)/He apatite analyses, which represent the time at which alpha particles from U and Th decay begin to accumulate as diffusion is effectively stopped when cooling through temperatures of c. 70°C - i.e. the age of eruption. The results suggest that
1. Damavand magmas are characterized by initial (230Th/232Th) = 0.65 - 0.90.
2. There is no significant "residence time" of apatite in the magmas prior to eruption
3. Some of the samples have apparent crystallization ages younger than that of eruption, clearly not a realistic scenario.
The young isochron "ages" can be reconciled with eruption ages, if the isochron slopes represent mixing rather than simply a crystallization event. Given that the whole rock samples are de facto mixtures, the most likely scenario is one of mixing relatively low 230Th/232Th cumulate material lying on the equiline into the whole rock - a suggestion which is consistent with petrographic observations and geochemical data.
Quaternary Glaciation in the Pindus Mountains, Northwest Greece (IP/754/0302)
The aim of the project is to establish the extent, dynamics and age of glaciation in the high Pindus Mountains of Northwest Greece. Four glacial events are recorded in the sedimentological and geomorphological records. During the glacial maximum of the last glacial stage, mean annual temperatures were ca. 8-9˚C lower than at present and mean annual precipitation greater than 2000 mm - similar to modern values. Maximum glacier extent in the Pindus Mountains has preceded the most severe arid phase of glacial cycles indicated in the pollen record because of the small size of the Pindus glaciers and their rapid response to climate change. The glacial sequence in the Pindus Mountains represents the best-dated and longest recognised record of glaciation in the Mediterranean region and provides a stratigraphical framework for Quaternary cold-stage climates in Greece.
Vadose zone calcite cements often coat large clasts, fill interclast voids and are usually localised deposits with little detrital quartz contamination. Sometimes the calcites are up to 5 cm thick and consist of multiple layers and, in places, small dripstones or stalactites, have developed within sediment voids. U-series data confirm the ages of five interstadial and two interglacial deposits that appear to have formed during intervals coinciding with high arboreal pollen percentages at Ioannina. This suggests that periods of cement formation were characterised by high moisture availability indicating warm phase climates.
The geomorphological and geological investigations, combined with the soil evidence and U-series dating enabled the development of a chronostratigraphical and geochronological framework for the cold-stage deposits of Greece. The glacial and periglacial sequence in the northern Pindus Mountains is now the best-dated sequence in this region and thus contributes to a lasting stratigraphical framework for the Quaternary of Greece.
SCIENCE SUPPORTED IN FY (2003/04):
Prof J Thomson, SOC, (IP/791/1103)
Uranium has a long residence time in seawater, so that there is a constant U concentration in seawater and hence a constant production of its daughter radionuclide 230Th. Unlike U, 230Th is particle-reactive and is rapidly removed from seawater along with sedimenting material. This results in a short residence time for 230Th in the ocean water column (10-40 y) and a predictable flux to the sea floor that depends only on water depth. As a result, 230Th approximates a constant flux tracer, and depositional fluxes of other elements into deep-ocean sediments and sediment traps are often estimated through normalization to 230Th fluxes.
However, a substantial proportion of the 230Th present in seawater is always found to be in solution rather than on particulate material. 230Th behaviour in the ocean water column is therefore modelled as a reversible equilibrium process. However, it has become evident, that the close balance between overlying water column production of 230Th and its inventory in the underlying sediments can break down in certain circumstances. This project aims to test whether the supply of 230Th excess from the water column to an area of enhanced deposition (contourite deposits as typified by Feni Drift) is limited by a water depth related supply as is usually assumed, or whether the material supplied to contourites is labelled according to the water depth of deposition, and can be supplied in any quantity.
Dr. Anson Mackay, UCL, (IP/793/1103)
Climatic change in southern Africa during the last interglacial.
The isotope project aims to use U-series methodology to date shifts in the diatom assemblage and stable isotope records from Tswaing Crater Lake that are likely to represent climatic changes during the last interglacial, and to thereby date the onset and end of the last interglacial in southern Africa. The climatic changes in southern Africa at the time of the last interglacial were probably caused by changes in global boundary conditions rather than by local changes in insolation determined by orbital precession. Furthermore, the last interglacial may have begun in the southern hemisphere before it began in the northern hemisphere, and it may have been interrupted by a global-scale decrease in temperatures
The U-series isotope results should indicate whether the changes in the climate reconstructed using diatoms and isotopic measurements were associated with the last interglacial, which has been dated to between 140/128 ka BP and 116 ka in the northern hemisphere and between 134 ka BP and 115 ka in Antarctica, or with changes in insolation determined by orbital precession, which exhibits cycles every 19/23 ka. If the climatic changes are associated with the last interglacial, the isotope results will show when the interglacial began and ended in southern Africa, and the timing of any climatic events during this period.