In India, in a arid area that I believe lies to the northeast, (but I'm going off memory right now, and that's dangerous) they found large (like
baseball size) globs of glass where the sand had been subjected to a brief period of EXTREME heat.
"Bob and I were absolutely flabbergasted at this core because it does look just exactly like impact brecchia," Becker told a news conference. In the cores, Becker's team found evidence for a layer of melted glass formed by an impact.
Originally posted by A5H
Actually lightning can create such features in sand. (Not circular) I've seen instances where glass items shaped like 'odd' tree brances have been formed. I'll try dig up a link for you...........
Regards,
Ash