Investigating aqueous and thermal alteration in carbonaceous chondrite meteorites
This PhD project aims to investigate the mineralogical, textural and chemical properties of the thermally altered CI, CM and CR chondrites.
This is a collaborative project between the Natural History Museum and the University of Manchester funded by the Science and Technology Facilities Council (STFC).
Primitive asteroids are the debris left over from planet formation. They are rocky time capsules that record the earliest conditions in the protoplanetary disk, and are important tracers for the processes and events that have shaped our solar system over the last ~4.5 billion years.
Two space missions, NASA's OSIRIS-REx and JAXA's Hyabusa2, are en route to the primitive asteroids Bennu and Ryugu, with the aim of characterising of their physical and chemical properties before returning to Earth with samples collected from the surface.
We can also learn about asteroids by studying meteorites in the laboratory. The chemical composition, mineralogy and textures found within meteorites enable us to reconstruct the geological history of asteroids. The aqueously altered CI, CM and CR carbonaceous chondrite meteorites are derived from water-rich asteroids, a possible source of extra-terrestrial H2O and organics to the Earth.
A small number of CI, CM and CR chondrites also underwent thermal metamorphism and may be good analogues for the types of materials that will be encountered on the surface of asteroids Bennu and Ryugu. However, disentangling the effects of both hydration and heating is challenging and important questions still remain regarding the cause, timing and duration of the alteration.
The aim of this project is to investigate the mineralogical, textural and chemical properties of the thermally altered CI, CM and CR chondrites.
The project has the potential to use a wide range of analytical techniques including optical and electron microscopes (SEM/EMPA), computed tomography (CT) scanning methods, and Raman spectroscopy. Isotopic measurements will be used to infer the timing of alteration, and dynamic heating experiments will constrain the mineralogical and chemical changes associated with thermal metamorphism.
The results of the project will provide new insights into the evolution of asteroids and a framework for understanding samples returned from asteroids Bennu and Ryugu.
This is a multi-disciplinary project utilising the world-class meteorite collection and analytical facilities available to the Planetary Materials Group at the Natural History Musuem, London, and the Isotope Geochemistry and Cosmochemistry Group at the University of Manchester.
The project would suit an enthusiastic individual with a keen interest in planetary science, and a strong background in the geosciences.
Nakamura T. (2005) Post-hydration thermal metamorphism of carbonaceous chondrites. Journal of Mineralogical & Petrological Sciences. 100:260‒272.
Nakamura T. (2006) Yamato 793321 CM chondrite: Dehydrated regolith material of a hydrous asteroid. Earth & Planetary Science Letters 242:26‒38.
Nakato A. et al. (2008) Evaluation of dehydration mechanism during heating of hydrous asteroids based on mineralogical and chemical analysis of naturally and experimentally heated CM chondrites. Earth, Planets & Space 60:855‒864.
Tonui E. K. et al. (2014) Petrographic, chemical and spectroscopic evidence for thermal metamorphism of carbonaceous chondrites I: CI and CM chondrites. Geochimica et Cosmochimica Acta 126:284‒306.
This project is funded for three and a half years as an STFC studentship, which will cover all fees and a student stipend if you are from the UK, or from the EU and meet residency requirements (settled status, or 3 years full-time residency in the UK). For full details on what is covered by the studentship please see the STFC guidance.
For informal enquiries or further information, please contact Dr Ashley King.
How to apply
Deadline: Wednesday 28 February 2018
Please send the following documents to Anna Hutson at the Postgraduate Office
- Curriculum vitae
- Covering letter outlining your interest in the PhD project, relevant skills training, experience and qualifications, and a statement of how this PhD project fits your career development plans.
- Transcripts of undergraduate and master's degree results.
- Two academic references including (if applicable) master's project supervisor.
Interview date: March 2018
Start date: October 2018