Tektite Tori???

I was recently forwarded a journal article dealing with tektite shapes (Stauffer & Butler, 2010) in which it is postulated that toroid-like (doughnut-like) forms are a logical end-point of radial flow and consequent central-thinning of a tektite disk spinning like a frisbie. A torus is to a revolving spheroid what teardrops are to rods and dumbbells. These authors do not picture a complete tektite torus, but do suggest flat-ended curved cylinders as possible torus fragments. I sorted through our collection looking for examples. Figure 1 shows the prime candidates.

Figure 1: Possible Indochinite toroid ring fragments

I also located two good examples of what would be the logical previous stage in the evolution of a torus. These are very deeplydished disk fragments. It is easy to imagine central concavities forming by radial flow in a spinning patty. Once this happens, frontal flight pressures
would accentuate the dishing, like blowing soap-bubbles. (I have often wondered if this is how big oblate sphereoids with large central bubbles form?). Figures 2 and 3 illustrate these intermediate stage specimens. From the form in figure 3 to the rupture of the centrally-thinned area forming a doughnut-shape is a short hop. I’ve never seen a complete unbroken Indochinite ring (if you’ve got one I’d love to hear from you—) but McColl (1997) describes a flanged Australite torus (which does not seem to be a detached button flange).

Figure 2: Intermediate stage: deep dishes.

Figure 3: Deep dish side view.

McColl, D.H., 1997, A Flanged Toroidal Tektite from Australia: Meteoritics & Planetary Science, v. 32 No. 6, pp 981-982.

Stauffer, M.R., and Butler, S.L., 2010, The Shapes of Splashform Tektites: Their Geometrical Analysis, Classification, and Mechanics of Formation: Earth, Moon, and Planets, V. 107, pp. 169-196.

About the Author

Norm Lehrman is a recently retired exploration geologist with over 45 years experience. His career involved fieldwork in over 35 countries on every continent except Antarctica. While stationed in Australia, Norm and his wife, Cookie, became interested in collecting Australites, which ultimately led to a generalized passion for tektites, impactites, meteorites and related materials. In 1999 they founded the Tektite Source business (www.TektiteSource.com) which has evolved into one of the world's premier providers of tektite and impactite specimens. Norm has retired to a ranch near Spokane, Washington, where they continue to serve tektite aficionados worldwide.

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