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Hemispheric grooves in starburst ray patterns are quite frequently
encountered in tektites from some areas. I attached no special significance to them until I saw about 50 of them
at once.
In the chaos of a major bolide impact, anything can happen once---but in this case there is a definite theme. As
can be seen in the images on this page, the starbursts present a very uniform appearance, and virtually always
radiate from an anomalous flattened or indented point. The grooves are commonly much smoother than the adjacent
tektite uplands, and often show taffy-like stretch marks crossing the groove.
It now seems clear that these starburst rays are just what they look like: collisional impact stress fractures
that ruptured the semi-brittle exterior skin of the tektite while the interior was still a stretchy, viscous liquid.
Whether the collision was with other stones flying in the ejecta cloud, or with the ground (or both) is uncertain.
The starburst rays are most commonly seen radiating from the rims of patties, but I have examples involving bars,
rods, teardrops, dumbells, and irregular forms. They may form on facial positions as well as rims
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