Mars image from Hubble Space Telescope

Professor Q&A with Craig Marshall, researching life on Mars

Craig Marshall
Craig Marshall, associate professor of geology

Part of Craig Marshall’s job as an associate professor of geology is to play with lasers. He’s a specialist in Raman spectroscopy, which involves using lasers to determine the molecular makeup of matter. Marshall frequently employs this technique to analyze minerals and crystals. One application he’s studying is whether Raman spectroscopy could help scientists find evidence of life on Mars.

He and his wife and colleague, Alison Olcott Marshall, are working together to improve the way scientists detect condensed aromatic carbon, thought to be a chemical signature of extraterrestrial life. By itself Raman spectroscopy is able to screen for carbonaceous material, but it can’t determine its source. They suggest using gas chromatography/mass spectroscopy to supplement Raman spectroscopy and develop more conclusive evidence of ancient extraterrestrial life. Currently, they’re extending this line of investigation by using Raman spectroscopy to analyze rocks from Earth that are similar to those on Mars.

We caught up with Craig to learn about the hidden beauty of crystals, how he found his calling, and who he’d invite to a dream dinner party.

Degrees: B.App.Sc Chemistry and Geology (University of Technology, Sydney, NSW Australia) 1997; Ph.D. Chemical Spectroscopy (University of Technology, Sydney, NSW Australia) 2001

Hometown: Glenbrook, NSW, Australia

Current Title: Associate Professor

Describe what you do: Currently my research is focused in two areas, firstly, evaluating the potential of Raman spectroscopy to characterize minerals and detect life on Mars, and secondly, working on approaches to better understand the puzzling Raman spectra of graphite and hematite.

Tell us a little about your career journey: Initially I didn’t know if I wanted to be a biology, geology, or chemistry major. I started my college career by enrolling in an Applied Science degree majoring in biotechnology. I ended up only doing two years of this degree and dropped out. Funnily enough after dropping out of this degree, I got a job in a biotech lab for the next 12 months. After this experience, things became clear to me, chemistry is what I wanted to do. I went back to college and majored in chemistry and minored in geology. Before my honours year (equivalent to a M.S degree), I spent a semester in industry and worked in a lead/zinc/silver mine in the Australian outback – which was a once in a lifetime experience!

After I finished my honours degree, I started my Ph.D., on the X-ray Photoelectron spectroscopy and Raman spectroscopy of thermally altered carbonaceous materials. When I finished my Ph.D. I did a postdoc on synthesizing novel nanostructured carbonaceous materials and characterizing them with Raman spectroscopy. My next postdoc was a complete change, and I found myself working at the Australian Center for Astrobiology. My work there focused on the application and evaluation of Raman spectroscopy as an analytical technique to take to Mars as a tool for life detection. After this, I got a faculty position in the Department of Chemistry, University of Sydney. I was there for about three years and then moved here in 2008.

Craig Marshall and his daughter collecting gypsum crystals in Oklahoma.
Craig Marshall and his daughter, Beatrix, collecting gypsum crystals from a salt flat in Oklahoma.

Throughout all of your research, what main lessons have you learned about the Earth or the universe that you would want an average person to know? At the atomic level crystals are just as beautiful as symmetrical structures we see with our eyes! Given that it is really hard to find unambiguous evidence for life on Early Earth, it will be an extremely difficult task to find evidence of past or present life on Mars!

My guilty pleasure: Chocolate and cookies!

Who would you invite to your dream dinner party? Being a Raman spectroscopist, I have to invite C.V. Raman (an Indian physicist and namesake of Raman spectroscopy). Also, I would invite Sir Donald Bradman (the best all-time cricketer), Dennis Lillee, and Rod Marsh (both Australian cricketers). A night of fun spectroscopy and cricket stories!

My best advice for college students: Make great use of all the resources available, study hard, but take time to enjoy the college experience!