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A New Furnace in Geology

March 20, 2013
The new Thermcraft furnace, donated by Mr. Thomas Crafton to the Geology Laboratory.

The new Thermcraft furnace, donated by Mr. Thomas Crafton to the Geology Laboratory.

Some mineral collectors have a strict rule: It only counts if you find it yourself.  I’m worse than that, because for me, it only counts if you grow it yourself.  You can call it mineral synthesis, or experimental petrology, or cook-n-look, but any way you dice it, I play with fire.  If research is a journey of self-discovery, then I discovered a pyromaniac. There’s no red shade of Revlon as lovely as ceramic and metal at 800-900°C.

It takes high temperature to make minerals, and high pressure, too. I tend to stick to the workhorse methods with temperatures below 900°C and pressures to about 2000 times atmospheric pressure. In geological terms, that’s upper crustal conditions, shallow volcanism or low pressure metamorphism.

Research Curator of Geology Chris Tacker holds a hot pressure vessel right out of the furnace.

Research Curator of Geology Chris Tacker holds a hot pressure vessel right out of the furnace.

I have special furnaces to take me to high temperature, since I can’t commute. They were USGS government surplus, never used. I flew to Denver a few days after September 11, and drove back with about $12,000 worth of never-used equipment. Then more equipment came via Federal Surplus from colleagues at NASA Johnson Space Center who were shutting down a lab. With help from my undergraduate research assistants, I stripped out the old USGS electronics and put in control boards from NASA, added a high pressure pump wedded to the old plumbing, and I was in business, making apatite crystals for fun and for grant money…

..Until the furnaces started to die, one by one. I started with four. Then I had one. I discovered why the furnaces were surplus: Replacement furnace elements were not readily available for a furnace that short. I could buy 12″ long elements off the shelf, but not 10″ long elements.

We were dead in the water. And it wasn’t just me. Over the years I’ve worked with Allen Glazner, professor and chairman of the geology department at UNC, and with his students, to grow crystals at geologically reasonable temperatures.

So I took the cheapest route, by winding a furnace by hand, out of desperation. It shorted at 600°C. We bought a 12″ long furnace replacement and modified a furnace shell to accept it. It was too long for the pressure vessels to reach the hot spot, that ideal place of uniform temperature.  New pressure vessels were out of the question, because they had to be machined from high-performance aircraft steel.

The lab resurrected thanks to a donation of furnace and electronics from Mr. Thomas Crafton from Thermcraft in Winston-Salem.  There are not many places that you can actually get a furnace for geological temperatures, and very, very few willing to donate one for free.  Mr. Crafton’s generous support of my research and of Museum-based science put us back in the game when there was absolutely no state government budget available.

Mr. Crafton and Thermcraft do not only support my predeliction to play with fire. The high temperature laboratory allows me to attract grant funding from the National Science Foundation.  Over the past four years, grant funding has allowed me to pay and train seven undergraduate geology students from Duke, NCSU and UNC. Four have gone on to graduate school, one is going to law school to study environmental and natural resource law, and two graduate this year. I have also worked in the summers with three geoscience interns, using equipment purchased on NSF grants. These students are also in graduate school or on their way. NSF funding also meant that I was completely off the state budget for more than three years.

My research focuses on fluorine, chlorine, hydroxide and carbonate in apatite group minerals. These elements are all related to the gases that drive catastrophic volcanic eruptions.  It may seem obscure to North Carolinians, but when Tambora blew in 1815 in Indonesia, Moravians near Winston Salem almost starved in the “year without summer” that followed.  My work on carbonate in apatite will be more quickly applied to materials that mimic teeth and bones, which are also apatite-like minerals.  It applies to you and yours if anyone needs a hip replacement.

So donations to our laboratories get leveraged way beyond the monetary value of the donation.  Thank you, Mr. Crafton and Thermcraft!

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