C. Samson¹, S. Butler², C. Fry¹, P. J. A. McCausland³, R. K. Herd^1,4, O. Sharomi⁵, R. J. Spiteri⁵ and M. Ralchenko¹

¹Department of Earth Sciences, Carleton University, Ottawa, Ontario, Canada
²Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
³Department of Earth Sciences, Western University, London, Ontario, Canada
⁴Earth Sciences Sector, Natural Resources Canada, Ottawa, Ontario, Canada
⁵Department of Computer Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada

Ten splash-form tektites from the Australasian strewn field, with masses ranging from 21.20 to 175.00 g and exhibiting a variety of shapes (teardrop, ellipsoid, dumbbell, disk), have been imaged using a high-resolution laser digitizer. Despite challenges due to the samples’ rounded shapes and pitted surfaces, the images were combined to create 3-D tektite models, which captured surface features with a high fidelity (≈30 voxel mm⁻²) and from which volume could be measured noninvasively. The laser-derived density for the tektites averaged 2.41 ± 0.11 g cm⁻³. Corresponding densities obtained via the Archimedean bead method averaged 2.36 ± 0.05 g cm⁻³. In addition to their curational value, the 3-D models can be used to calculate the tektites’ moments of inertia and rotation periods while in flight, as a probe of their formation environment. Typical tektite rotation periods are estimated to be on the order of 1 s. Numerical simulations of air flow around the models at Reynolds numbers ranging from 1 to 10⁶ suggest that the relative velocity of the tektites with respect to the air must have been <10 m s⁻¹ during viscous deformation. This low relative velocity is consistent with tektite material being carried along by expanding gases in the early time following the impact.

Reference
Samson C, Butler S, Fry C, McCausland PJA, Herd RK, Sharomi O, Spiteri RJ and Ralchenko M (in press) 3-D laser images of splash-form tektites and their use in aerodynamic numerical simulations of tektite formation. Meteoritics & Planetary Science
[doi:10.1111/maps.12287]
Published by arrangement with John Wiley & Sons

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