Dr. Anton Chakhmouradian teaches alkaline and carbonatitic systems at the University of Manitoba. I believe that his research is both top-notch and absolutely critical for the furthering of our understanding of rare earths in various geologic settings. This interview was conducted by submitting questions to Dr. Chakhmouradian which he answered and returned on 3 May 2010.
Where did you receive your education?
My alma mater is St. Petersburg State University, the second largest school in Russia. For my master’s and doctoral degrees, I studied in the Department of Mineralogy. The Russian postsecondary education used to be very different from the North American. For one thing, so many young people of my generation were interested in geology that each specialized department within the Faculty of Geology (Mineralogy, Paleontology, etc.) was graduating several students every year. With the collapse of the Soviet Union, that interest has dwindled due to the shrinking job market for geologists, and many of my former classmates have ultimately chosen alternative careers, but others have stuck with geology and don’t regret it.
When and how did you get interested in the rare earths?
I was fortunate that way because several of my former profs were involved in the study of the famous Kola alkaline province from the 1950s through the 80s, so I, too, “got hooked”. Both of my thesis advisors were great mentors who passed their knowledge and passion for geology and alkaline rocks on to me. For my thesis, they encouraged me to re-examine the perovskite mineral group, which included loparite, the principal source of rare-earth metals for the Russian industry to this day. Basically, I have been working on rare-earth minerals since 1992 when I first visited Kola and the Lovozero Mountains, where loparite has been mined for the past 60 years.
Was there a particular person or project that was pivotal in your studies?
There was no single person that I can definitively credit (or blame) for my choice of a career path. In addition to my advisors, whom I already mentioned, I should definitely acknowledge my other mentors and senior colleagues who nurtured that interest and contributed to my development as a scientist, including Roger Mitchell, Anatoly Zaitsev and Rudy Wenk. And, as far as the pivotal project goes, it definitely was my PhD dissertation on the Kola perovskites. These minerals are an important repository for REEs, but, besides that, they commonly occur in rocks hosting all sorts of REE mineralization, like carbonatites and nepheline syenites. Some contain apatite loaded with light REEs, others garnet with Y and heavy REEs, others something else yet, like REE carbonates, monazite, or loparite. Every project I have been involved in taught me something new about REEs, helping me fine-tune my methodology and find new exciting avenues of research.
How important is the study of rare earths?
To just say that it is important would be somewhat of an understatement. In a lot of ways, REEs are to us now like aluminum was to people of the late 1800s. Few scientists realized the real value of aluminum at the time, but can you imagine the aerospace, automobile and even the packaging industries of today without this metal?
What is your specialty within the study of REEs?
I am a mineralogist/geochemist by training, so my professional interests revolve around the various types of REE mineralization that we find in rocks of alkaline affinity. Although many great minds have worked in this field, many key issues of REE geochemistry and mineralization remain unresolved. Why, for example, some carbonatites are loaded with bastnäsite, whereas others contain REEs barely above the background levels? Why is heavy REE mineralization prevalent in alkali granites, but so rare in carbonatites?
I bet, every company and exploration geologist would like to find the practically implementable answers to these questions, but it is generally academics, who have the time and instrumental capabilities to dedicate themselves to such long-run goals. REEs are not the only type of resource that interests me. I also work on niobium, tantalum, titanium, zirconium and uranium-thorium minerals. Anyone interested can look at my research “portfolio” on my website:
http://umanitoba.ca/geoscience/faculty/arc/
Where have you explored for REEs?
Because I am not an exploration geologist, I have never really explored for REEs, in the conventional sense of that word, anyway. Exploration requires weeks and months of reconnaissance and fieldwork, which would leave me essentially no time for teaching, student supervision, public outreach and many other activities that are part of my current job. I like my job too much to trade it for full-time REE exploration. I have, however, consulted for a number of companies.
Whenever possible, I try to get out there and see the rocks, touch, scratch and sample them myself rather than using someone else’s material. To me, nothing is like this first-hand visual experience.
What are some of the most interesting sites that you have studied?
I have seen and worked on many carbonatite and alkaline localities in the Northern Hemisphere and they are all interesting and special in their own individual ways. I find it difficult to rank them in any way, because each of the sites I have visited had something special about it, and it may not necessarily have been anything to do with its economic potential.
To this day, for example, I am very partial to the Murun alkaline complex in eastern Siberia, even though it would be a boring place to explore for REEs. There are some beautiful carbonatites and really exotic silicate rocks at Murun, but they are generally poor in REEs. My wife Katya, who is also a mineralogist and carbonatite expert, found a few specs of burbankite in these carbonatites, but that was it. Nonetheless, I hold this place very dear to my heart because of its rugged beauty, its unique gemstones, and other things that I connect to at some conscious or subconscious level.
Geologically, the most complex and, therefore, interesting of all the places I have been to are probably the alkaline and carbonatite complexes of Kola Peninsula. Places like the giant Khibiny and Lovozero intrusions in central Kola have been explored and studied by hundreds of people, but there is probably still enough work for many more generations of scientists to come.
The most geologically challenging, least explored and, hence, most fun to work on are the recently discovered carbonatites in central Manitoba.
How do you decide how to collect samples?
Optimally, I would like to have some understanding of the place where I would be sampling and its rocks beforehand. If any material collected by my predecessors is available for study, that is ideal. I would look at some rocks and thin sections and try to relate what I see under the microscope to what I read about the place and its geology in the literature.
Coming to the field equipped not only with the right tools but also with knowledge gives you a great edge and allows you to conduct sampling in a systematic fashion. When you are in a completely unfamiliar place, choosing the right sampling strategy can be a difficult task. I’d say there is no unified approach to sampling. It all depends on what you are actually sampling (bedrock, loose material of unknown provenance, drill core, etc.), as well as on your maneuverability and scope of your fieldwork. Is your goal to sample methodically one large outcrop, or you will be moving from site to site? Is there any evidence of intense weathering, metasomatism or metamorphic overprint in the rocks you are sampling? What types of analysis do you have in mind for this material?… You have to have clear answers to all these and many other questions before you can work out the right sampling strategy – right for this particular place and the very specific goals you are trying to achieve.
The only generalization I can make is that your samples have to represent the geology of the sampling site as accurately as possible. Also, I teach my students that, if you want to do a thorough job as a researcher or consultant, maintain a meticulous written and photographic record of what you are sampling. I spend as much time as I can at an outcrop, looking at the same rocks, contacts and structures from different vantage points, jotting down my notes, snapping lots of pictures and trying to come up with some plausible story for how this all formed while, hopefully, enjoying a cup of tea fresh off the campfire.
What kind of scientific equipment do you use to research REE samples?
In my research, I use a wide range of analytical techniques, from the “old-fashioned” immersion oils and X-ray powder diffraction to things like Raman micro-spectroscopy, which allows you to rapidly identify minerals based on how they interact with laser light – whatever gets the job done.
Step one is always petrographic analysis using polarizing microscopy, but it is never enough just by itself because it does not let you distinguish between optically similar minerals and does little for grains smaller than 50 microns.
I teach my students to follow up the petrography with energy-dispersive analysis, back-scattered-electron imaging and Raman micro-spectroscopy to make sure they’d be able to point at any grain in their rock and say what that is.
Depending on the task at hand, available budget and degree of my interest, I can then decide if any advanced, and generally more expensive, work needs to be done. For example, I often use stable-isotope analysis because it helps distinguish carbonatites from other rock types; to figure out the distribution of REEs in my samples, I use laser-ablation mass-spectrometry, and so forth… There is an instrument to tackle almost any problem one can think of. And, like I said, the problem does not have to be of practical nature – I am a scientist, after all, and sometimes “get carried away” in what I do.
If my work on a project turns up something of purely academic interest, I sometimes decide to pursue the new research lead at my own expense. For example, I once did some work for Avalon and stumbled across an unusual mineral which was of no economic value to anyone, but had a very unusual chemistry. So, I asked Don Bubar for his permission to use their material for study, and it turned out to be a new mineral that my colleague Luca Medici and I described in the European Journal of Mineralogy a few years ago.
What advantage does the equipment give you?
It is as essential as an acoustic aid to a hearing-impaired person, only in so many more ways and at many different levels. It gives you the advantage of knowing – not guessing – but knowing exactly what type of rocks and minerals you are dealing with, what their composition is, and everything else you will ever need to know.
The basic equipment, like a petrographic microscope, is well worth an investment, while other, more expensive instruments like an electron microprobe may not be affordable, but should still be at an arm’s length when you need them.
Just one example: Eu is about one hundred times more expensive than Ce. Variations in Eu content in ore minerals such as monazite can be as much as one order of magnitude, which means a tonne of ore can be worth hundreds of dollars or thousands at the same TREO grade. You won’t be able to say if it is hundreds or thousands unless you “go analytical”.
Anyone working on such complex types of mineral resources as rare earths should develop a network of willing and expert collaborators in academia to have access to the equipment and analytical expertise.
More next week…