Long horizontal streaks of spider lightning below the base of a storm cloud, Tucson Mountains, … [+]
A team of scientists discovered what could be a new mineral group in a fulgurite – the ‘fossilized remains’ of a lightening strike.
Lightning – a short-lasting but very high-energy event – can cause unique chemical reactions resulting in new minerals. Similar minerals can be found in meteorites and asteroids, likely the results of high temperatures and pressure conditions during the impacts between celestial bodies. Fulgurites can be seen as a transitional form between space minerals and minerals found on Earth.
“We have never seen this material occur naturally on Earth—minerals similar to it can be found in meteorites and space, but we’ve never seen this exact material anywhere,” said Matthew Pasek, professor at the University of South Florida and coauthor of the study.
“When lightning strikes a tree, the ground typically explodes out and the surrounding grass dies, forming a scar and sending electric discharge through nearby rock, soil and sand, forming fulgurites.”
After lightning struck a tree in a New Port Richey neighborhood in Florida, the homeowners discovered that the intense heat of the lightening strike melted the sediment around the tree roots, forming droplets and tube-like fulgurites made of a glass-like material. Pasek purchased some samples and later began a collaboration with Luca Bindi, a professor of mineralogy and crystallography at the University of Florence in Italy.
Sample of the New Port Richey fulgurite and microscopic images of the new minerals.
Fulgurites are often found in desert areas, when a lightening strikes melts the desert sand forming a silicon-dioxide rich glassy material. But the shows an unusual chemical composition, rich in carbon, iron and phosphorus.
In wet environments, such as in Florida, Pasek says iron will often accumulate and encrust tree roots. In this case, not only did the lightning strike combust the iron on the tree roots, but it combusted the naturally occurring carbon in the tree as well. The two elements led to a chemical reaction that created a new crystal-like matter inside the fulgurite.
Experiments to recreate a similar substance in the lab have yet to be successful. Further investigations are needed to determine if it could be officially declared a new mineral.
The study “Routes to reduction of phosphate by high-energy events” was published in the journal Communications Earth & Environment. Material provided by University of South Florida.
