When lightning strikes sand or soil, it melts and fuses grains into features that some have called petrified lightning bolts. Their scientific name is fulgurites, after fulgur, the Latin word for lightning.
Fulgurites are branched, thin, hollow tubes usually 1 or 2 inches in diameter and a few feet to tens of feet long. They are rough on the outside (where sand grains and other material stick to the molten material) but glassy smooth on the inside, with many bubble holes produced by vaporized gases.
They usually are considered mere curiosities, but a recent bit of research reported in the Feb [??] issue of the journal Geology put fulgurites to a scientific use, to obtain 15,000-year-old climate data.
They used TL to date them. Doesn't seem to anything new here as archaeologists have done a lot of climate reconstructions in the Libyan desert. Guess it's one more piece of data though, and might be useful in cases where there is no archy data.