Carbon in primitive meteorites: The relationship between organic matter and minerals in protoplanetary dust

Natural History Museum

PhD 3.5 years London, UK

Uploaded 12 Jun 2019

Job Description

This PhD will use state-of-the-art imaging techniques to study the relationship between organics and minerals in the matrix of primitive carbonaceous chondrite meteorites.

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

Apply for this project

Read the eligibility criteria and application guidance below, then send your application to [email protected]

Application deadline: Friday 21 June 2019.

Apply now

Primitive carbonaceous chondrite meteorites provide a detailed record of the geological processes and events that have shaped our solar system over the last 4.5 billion years. Carbonaceous chondrites are dominated by a fine-grained matrix of amorphous and crystalline silicates, oxides, sulphides and metal that have remained largely unaltered since the time they were accreted into an asteroid.

The matrix can also contain up to 5 wt% carbon in a wide variety of forms such as nanodiamonds, carbonates and organic materials including soluble molecules and unstructured, kerogen-like insoluble organic matter (IOM).

The abundance and diversity of the organic materials present within carbonaceous chondrites has led to suggestions that they may have seeded the early Earth, and potentially the other rocky inner solar system planets, with prebiotic molecules that went on to play a crucial role in the formation of life.

icegrain-interstellar-two-column

A cartoon diagram from astrochem.org describing the relationship between interstellar dust and primitive organic matter prior to accretion on an asteroid

Astronomical observations of young star systems and interstellar space find organic and elemental carbon associated with dust. In the cold, outer regions of the early solar system amorphous and crystalline silicates likely acted as nucleation sites for the formation and processing of organic materials. Presolar grains on the other hand are thought to predate the Sun’s formation and additionally carry information related to the interstellar space and the solar nebula.

The mineralogy and chemistry of the fine-grained matrix that preserves these primitive carbonaceous materials varies across meteorite groups, providing a broad record of the chemical and physical processes that were active during accretion and early parent body processing. However, the spatial and textural relationship between organic matter and the host matrix minerals in carbonaceous chondrites are poorly understood.

The complex and heterogeneous nature of the organic materials, and the sub-micron grain size of the matrix minerals, means that imaging techniques with nanometre scale resolution are essential for studying them.

This project will use a suite of state-of-the-art imaging techniques to obtain in-situ, spatially correlated chemical, spectroscopic and diffraction information in order to understand the relationship between organics and minerals in the matrix of carbonaceous chondrites.

colony-meteorite-two-column

An elemental X-ray map of the CO3.0 carbonaceous chondrite Colony collected on a scanning electron microscope by Enrica Bonato of the Planetary Materials Group at the Natural History Museum.Millimetre sized chondrules, calcium aluminium rich inclusions (CAIs) and silicate fragments are bound together by a very fine grained matrix of amorphous and crystalline minerals and carbonaceous materials.  Blue = Si; green = Mg; yellow = Ca; white = Al; red = Fe.

This project is particularly timely with JAXA’s Hayabusa-2 and NASA’s OSIRIS-REx missions having recently arrived at the carbonaceous asteroids Ryugu and Bennu, with both missions aiming to return samples from the asteroid surfaces in 2020 and 2023 respectively.

Supervision and training

The student will become integrated into the Planetary Materials Group at the Natural History Museum (NHM) and the Plymouth Planets Group at the University of Plymouth. They will have the opportunity to study samples from one of the finest meteorite collections in the world at the NHM.

Electron microscopy, including scanning and transmission electron microscopy (SEM and TEM), infrared (IR), Raman and fluorescence spectroscopy, and thermal analysis will be performed at the NHM’s Image and Analysis Laboratories, and in Plymouth Electron Microscopy Centre (University of Plymouth).

Micro- and nano-scale X-ray and IR microscopy will be undertaken at international synchrotron facilities such as the UK’s Diamond Light Source, using X-ray nanoprobes, scanning transmission X-ray microscopy (STXM) and near-field / micro IR microscopy.

Eligibility

Projects are funded for 3.5 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.

We seek an enthusiastic person for this project with a strong background in geology or planetary sciences, or other physical sciences, and with an interest in applying analytical mineralogy to a planetary science context.

For informal enquiries or further information, please contact Dr Paul Schofield.

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

We seek an enthusiastic person for this project with a strong background in geology or planetary sciences, or other physical sciences, and with an interest in applying analytical mineralogy to a planetary science context.