The evolution of material in the inner solar system: Elucidating the history of enstatite chondrites

Natural History Museum

PhD 3.5 years London, UK

Uploaded 12 Jun 2019

Job Description

This project will investigate the chemical and isotope systematics of enstatite chondrite meteorites to understand the evolution of the inner solar system.

This is a collaborative project between the Natural History Museum and the Open University and is funded by the STFC for three and a half years.

Summary

The solar system formed from a disk of dust and gas, and this can be analysed using meteorites that date from this time. The student will undertake a detailed study of materials that date from this time and place - specifically the enstatite meteorites, which may have originated in the innermost part of the disk.

Chondritic meteorites are relicts from the early solar system composed largely of sub-spherical μm-to-mm sized objects called chondrules. Enstatite chondrites are isotopic twins to the Earth-Moon system, suggesting a genetic connection.

In addition, recent orbital data from the MESSENGER mission to Mercury have shown that it has chemical similarities to the enstatite chondrites, for example high sulphur abundances and Mg/Si ratios.

This rare meteorite group (only around 500 enstatite meteorites are known) are therefore highly likely to be products of the inner solar system; if not direct ancestors then possible 'aunts' to the terrestrial planets.

The enstatite chondrites are remarkable for their extremely reduced mineralogy; sulphides and metal are very abundant and the main silicate is FeO-poor enstatite. Reduced C and N bearing minerals such as SiC, graphite and nierite (Si3N4) are relatively abundant. High temperature solids such as calcium aluminium-rich inclusions (CAIs) are rare.

The student will analyse the chemistry and isotope systematics of individual, pristine, chondrules, CAIs and isolated sulphide grains from the most primitive available enstatite chondrites.

kota-kota-enstatite-two-column

Element map of Kota Kota (EH3) section. Magnesium = green, Silicon = blue. Field of view is approximately 5mm across. Rounded chondrules are embedded in a fine grained matrix. The most common silicate is enstatite (blue-green). Rare forsterite (pale green) is observed in chondrule cores and may be relict from a time prior to reduction by a silicon and sulphur rich gas.

Methodology

We will use petrographic techniques to locate possible precursor grains in the chondrules. By comparing these to later generated components we can assess how the inner protoplanetary disk composition evolves during its several million year lifetime.

Age information will be acquired by measuring the initial abundance of 26Al/27Al in suitable phases (e.g. chondrule mesostasis) at the Open University to enable this compositional evolution to be monitored quantitatively.

We will analyse the composition of trace elements in the major phases in enstatite chondrites using ICP-MS and Synchrotron x-ray microscopy as a tool to track the evolution of chondrules and their interaction with the surrounding gas.

Eligibility

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.

The project would suit an enthusiastic individual with a keen interest in planetary science, and a strong background in the geosciences.

For informal enquiries or further information, please contact Prof Sara Russell.

How to apply

Deadline: Friday 21 June 2019

Please send the following documents to the Postgraduate Office at [email protected]

  • 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.

Start date: October 2019

Person Specification

The project would suit an enthusiastic individual with a keen interest in planetary science, and a strong background in the geosciences.

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