We are currently looking for a candidate for a PhD position at Utrecht University concerning the project: Testing the robustness of the sulphur stable isotope biomarker and palaeoredox indicator for planetary exploration.
Stable sulphur isotope ratios are likely to be a key tool in future planetary exploration missions for identifying possible traces of life, constraining atmospheric composition and surface redox conditions, especially on Mars where extensive sulphate deposits were recently discovered. To calibrate the extraterrestrial record it is of critical importance to explain the observed variation in terrestrial S isotopes through time. Calibration relies on the analysis of both sulphide and sulphate minerals, predominantly pyrite and baryte preserved in sedimentary rocks and typically metamorphosed to between lower greenschist (>300oC, 0.1-0.5 GPa) and granulite facies (600-900oC, 0.2-1.2 GPa).
Recrystallization and interaction with other minerals and/or fluids during metamorphism can result in homogenization or modification of the S isotope signature. Impact metamorphism may also prove to be a problem in interpreting the Martian record.
In this study we intend to quantify the effects of metamorphism on the preservation of original S isotopic variations in pyrite and baryte, by experimentally re-equilibrating natural and synthetic samples with fluids over a range of oxidizing and reducing conditions from Greenschist (350-5250C, 0.2-1.0 GPa) to Amphibolite facies (525-725oC, 0.2-1.2 GPa).
We will also investigate the effect of pressure jarosite alteration kinetics at 2-3 GPa. Experiments will employ high-pressure hydrothermal annealing and piston cylinder equipment. The specific aim is to assess over which planetary environments S isotopes can be used as a robust biomarker and palaeoredox indicator. We expect our results to give an impetus to future exploration of stable isotopic variations on Mars or other extraterrestrial sites.
The project involves scientists at the Free University Amsterdam, Swedish Museum of Natural History, Edinburgh University and Royal Holloway University of London with funding provided by the Netherlands Organization for Scientific Research.
Qualifications
We are looking for a highly motivated individual with an MSc or equivalent degree in Earth Sciences or a related field. Experience in stable isotope geochemistry, mineralogy and experimental rock deformation would be an advantage. He/she communicates easily in English, both verbally as in writing.
Terms of employment
We offer a full-time PhD-position for 4 years, contingent on a satisfactory performance. Monthly salary starts at € 2,000.- and is expected to increase to € 2,558.- in the fourth year of appointment. We also offer a pension scheme, a collective health insurance and flexible employment conditions. Conditions are based on the Collective Employment Agreement of the Dutch Universities and are supplemented with a holiday allowance of 8 % per year and a year-end bonus of 6,4%.
Further details
For more information please contact Dr Paul Mason (mason@geo.uu.nl). You can also visit the website of Utrecht University's Institute of Earth Sciences: http://www.geo.uu.nl/ivau.
How to apply
Applications, including a motivation for this position, a statement of your research interests, a curriculum vitae, a small abstract of MSc-thesis or equivalent, and the names and addresses of two referees, should be submitted to
the Faculty of Geosciences,
Personnel Department,
P.O. Box 80.115, 3508 TC
Utrecht, the Netherlands
or submitted by e-mail to: PenO@geo.uu.nl.
The position is open until filled, but we would like to receive your application before September 12, 2008. The prefered starting date is between October 1, 2008 and February 1, 2009.
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