For prospective students and collaborators

How to work with me on mantle volatiles, experimental petrology, and origins-of-life geochemistry.

I supervise undergraduate, masters, and (as a co-supervisor) PhD projects through the Department of Earth Sciences at Cambridge. If you’re interested in any of the threads on my research page, get in touch — even informally.

What I’m looking for

You don’t need a perfect background. You do need:

  • Curiosity about the deep Earth. Things that move on million-year timescales, at gigapascals, or in vanishingly small concentrations.
  • Comfort with quantitative work. Most of my projects involve a meaningful amount of data analysis (Python or R). If you don’t know either yet, that is fine and fixable; willingness to learn is what matters.
  • Honesty about uncertainty. Geochemistry runs on error bars. The best students I have worked with are the ones who treat “I’m not sure” as a useful sentence rather than a failure.

I am especially interested in supervising students from backgrounds underrepresented in Earth Sciences. The Wellcome Trust EDIA internship I ran in 2023 was one of the more rewarding things I’ve done in this job, and I am actively looking for similar opportunities.

Project ideas

These are starting points — real projects evolve from your interests in conversation.

Carbon in spreading-ridge cumulates
Microanalysis of plagioclase-hosted inclusions and gabbroic samples to map how volatile carbon redistributes during cumulate formation. Suits a student who likes microscopy and careful measurement, and is willing to learn SIMS.

Hydrothermal vent geochemistry as prebiotic chemistry
Piston-cylinder and gas-mixing furnace experiments simulating Hadean vent conditions — what minerals form, what fluids result, what organic chemistry follows. Cross-cuts geology and origins-of-life biochemistry. Suits a student who wants something interdisciplinary and isn’t afraid of an experimental learning curve.

Olivine partitioning, revisited
Lattice-strain modelling of trace-element partitioning between olivine and silicate melts, using new experimental and natural data. Heavier on theory and statistics; lighter on lab time.

Mars mantle melting
Comparing experimental constraints with InSight seismology and meteorite (NWA) chemistry. A modelling- and synthesis-heavy project; well suited to a student preparing to work on returned samples in the next decade.

Practicalities

  • Cambridge undergraduates — Part II and Part III project supervision, in coordination with the Department. Reach out in early Michaelmas of the year before your project.
  • Masters / Part III — happy to discuss extended projects.
  • PhD students — I co-supervise PhDs in the Shorttle group; if you’re applying to Cambridge Earth Sciences and would like to work on something that overlaps with my interests, email me before submitting your application so we can talk through fit.
  • Visiting researchers / mentees — I currently mentor PhD students at Münster and Cambridge on micro-analytical methods and experimental work. Open to similar arrangements elsewhere.

How to get in touch

The best email is joshuajshea@gmail.com. Tell me:

  1. Where you are in your studies and what you’ve worked on.
  2. Which thread (or specific project idea) caught your eye, and why.
  3. What you’d like to get out of the project.

A short paragraph on each is plenty — please don’t send a multi-page motivation letter for a first email. If there’s a fit I’ll suggest a quick conversation.